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Netters Atlas de Neurologia


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  • 1. Atlas of Neuroanatomy and Neurophysiology Selections from the Netter Collection of Medical Illustrations Illustrations by Frank H. Netter, MD John A. Craig, MD James Perkins, MS, MFA Text by John T. Hansen, PhD Bruce M. Koeppen, MD, PhD
  • 2. Atlas of Neuroanatomy and Neurophysiology Selections from the Netter Collection of Medical Illustrations Copyright ©2002 Icon Custom Communications. All rights reserved. The contents of this book may not be reproduced in any form without written authorization from Icon Custom Communications. Requests for permission should be addressed to Permissions Department, Icon Custom Communications, 295 North St., Teterboro NJ 07608, or can be made at www. NOTICE Every effort has been taken to confirm the accuracy of the information presented. Neither the publisher nor the authors can be held responsible for errors or for any consequences arising from the use of the information contained herein, and make no warranty, expressed or implied, with respect to the contents of the publication. Printed in U.S.A.
  • 3. Foreword Frank Netter: The Physician, The Artist, The Art This selection of the art of Dr. Frank H. Netter on neuroanatomy and neurophysiology is drawn from the Atlas of Human Anatomy and Netter’s Atlas of Human Physiology. Viewing these pictures again prompts reflection on Dr. Netter’s work and his roles as physician and artist. Frank H. Netter was born in 1906 in New York City. He pursued his artistic muse at the Sorbonne, the Art Student’s League, and the National Academy of Design before entering medical school at New York University, where he received his M.D. degree in 1931. During his student years, Dr. Netter’s notebook sketches attracted the attention of the medical faculty and other physicians, allow- ing him to augment his income by illustrating articles and textbooks. He continued illustrating as a sideline after establishing a surgical practice in 1933, but ultimately opted to give up his practice in favor of a full-time commitment to art. After service in the United States Army during the Second World War, Dr. Netter began his long collaboration with the CIBA Pharmaceutical Company (now Novartis Pharmaceuticals). This 45-year partnership resulted in the production of the extraordinary collection of medical art so familiar to physicians and other medical professionals worldwide. When Dr. Netter’s work is discussed, attention is focused primarily on Netter the artist and only secondarily on Netter the physician. As a student of Dr. Netter’s work for more than forty years, I can say that the true strength of a Netter illustration was always established well before brush was laid to paper. In that respect each plate is more of an intellectual than an artistic or aesthetic exercise. It is easy to appreciate the aesthetic qualities of Dr. Netter’s work, but to overlook its intellectual quali- ties is to miss the real strength and intent of the art. This intellectual process requires thorough under- standing of the topic, as Dr. Netter wrote: “Strange as it may seem, the hardest part of making a med- ical picture is not the drawing at all. It is the planning, the conception, the determination of point of view and the approach which will best clarify the subject which takes the most effort.” Years before the inception of “the integrated curriculum,” Netter the physician realized that a good medical illustration can include clinical information and physiologic functions as well as anato- my. In pursuit of this principle Dr. Netter often integrates pertinent basic and clinical science ele- ments in his anatomic interpretations. Although he was chided for this heresy by a prominent European anatomy professor, many generations of students training to be physicians rather than anatomists have appreciated Dr. Netter’s concept. The integration of physiology and clinical medicine with anatomy has led Dr. Netter to another, more subtle, choice in his art. Many texts and atlases published during the period of Dr. Netter’s career depict anatomy clearly based on cadaver specimens with renderings of shrunken and shriv- eled tissues and organs. Netter the physician chose to render “live” versions of these structures—not shriveled, colorless, formaldehyde-soaked tissues, but plump, robust organs, glowing with color! The value of Dr. Netter’s approach is clearly demonstrated by the plates in this selection. John A. Craig, MD Austin, Texas
  • 4. This volume brings together two distinct but related aspects of the work of Frank H. Netter, MD, and associated artists. Netter is best known as the creator of the Atlas of Human Anatomy, a comprehensive textbook of gross anatomy that has become the standard atlas for students of the subject. But Netter’s work included far more than anatomical art. In the pages of Clinical Symposia, a series of mono- graphs published over a period of more than 50 years, and in The Netter Collection of Medical Illustrations, this premier medical artist created superb illustrations of biological and physiological processes, disease pathology, clinical presentations, and medical procedures. As a service to the medical community, Novartis Pharmaceuticals has commis- sioned this special edition of Netter’s work, which includes his beautiful and instructive illustrations of nervous system anatomy as well as his depictions of neurophysiological concepts and functions. We hope that readers will find Dr. Netter’s renderings of neurological form and function interesting and useful.
  • 5. Click any title below to link to that plate. Part 1 Neuroanatomy Cerebrum—Medial Views . . . . . . . . . . . . . . . . . 2 Oculomotor (III), Trochlear (IV) and Abducent (VI) Nerves: Schema. . . . . . . 27 Cerebrum—Inferior View. . . . . . . . . . . . . . . . . . 3 Trigeminal Nerve (V): Schema . . . . . . . . . . . . 28 Basal Nuclei (Ganglia). . . . . . . . . . . . . . . . . . . . 4 Facial Nerve (VII): Schema . . . . . . . . . . . . . . . 29 Thalamus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Vestibulocochlear Nerve (VIII): Schema. . . . . 30 Cerebellum . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Glossopharyngeal Nerve (IX): Schema . . . . . . 31 Brainstem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Vagus Nerve (X): Schema . . . . . . . . . . . . . . . . 32 Fourth Ventricle and Cerebellum . . . . . . . . . . . 8 Accessory Nerve (XI): Schema . . . . . . . . . . . . 33 Accessory Nerve (XI) . . . . . . . . . . . . . . . . . . . . 9 Hypoglossal Nerve (XII): Schema . . . . . . . . . . 34 Arteries to Brain and Meninges . . . . . . . . . . . 10 Nerves of Heart . . . . . . . . . . . . . . . . . . . . . . . . 35 Arteries to Brain: Schema . . . . . . . . . . . . . . . . 11 Autonomic Nerves Arteries of Brain: Inferior Views . . . . . . . . . . . 12 and Ganglia of Abdomen. . . . . . . . . . . . . . . 36 Cerebral Arterial Circle (Willis) . . . . . . . . . . . 13 Nerves of Stomach and Duodenum . . . . . . . . 37 Arteries of Brain: Frontal View and Section . . 14 Nerves of Stomach and Duodenum (continued) . . . . . . . . . . . . 38 Arteries of Brain: Lateral and Medial Views . . . . . . . . . . . . . . . 15 Nerves of Small Intestine . . . . . . . . . . . . . . . . 39 Arteries of Posterior Cranial Fossa . . . . . . . . . 16 Nerves of Large Intestine . . . . . . . . . . . . . . . . 40 Veins of Posterior Cranial Fossa . . . . . . . . . . . 17 Nerves of Kidneys, Ureters and Urinary Bladder . . . . . . . . . . . . 41 Deep Veins of Brain. . . . . . . . . . . . . . . . . . . . . 18 Nerves of Pelvic Viscera: Male . . . . . . . . . . . . 42 Subependymal Veins of Brain . . . . . . . . . . . . . 19 Nerves of Pelvic Viscera: Female . . . . . . . . . . 43 Hypothalamus and Hypophysis . . . . . . . . . . . 20 Median Nerve . . . . . . . . . . . . . . . . . . . . . . . . . 44 Arteries and Veins of Hypothalamus and Hypophysis . . . . . . . . 21 Ulnar Nerve . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Relation of Spinal Nerve Roots to Vertebrae . . . 22 Radial Nerve in Arm and Nerves of Posterior Shoulder . . . . . . . . 46 Autonomic Nervous System: General Topography. . . . . . . . . . . . . . . . . . . 23 Radial Nerve in Forearm . . . . . . . . . . . . . . . . . 47 Spinal Nerve Origin: Cross Sections. . . . . . . . 24 Sciatic Nerve and Posterior Cutaneous Nerve of Thigh . . . . . . . . . . . . . . 48 Olfactory Nerve (I): Schema . . . . . . . . . . . . . . 25 Tibial Nerve . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Optic Nerve (II) (Visual Pathway): Schema . . . . . . . . . . . . . . 26 Common Fibular (Peroneal) Nerve. . . . . . . . . 50
  • 6. NEUROANATOMY Cerebrum: Medial Views Sagittal section of Paracentral sulcus Cingulate gyrus brain in situ Central sulcus (Rolando) Cingulate sulcus Paracentral lobule Medial frontal gyrus Marginal sulcus Sulcus of corpus callosum Corpus callosum Fornix Precuneus Septum pellucidum Superior sagittal sinus Interventricular Choroid plexus foramen (Monro) of 3rd ventricle Interthalamic Stria medullaris adhesion of thalamus Parietooccipital Thalamus and sulcus 3rd ventricle Cuneus Subcallosal (parolfactory) Habenular area commissure Pineal body Anterior commissure Posterior commissure Subcallosal Calcarine gyrus sulcus Hypothalamic Straight sinus sulcus in tentorium Lamina cerebelli terminalis Great cerebral vein Supra- (Galen) optic Superior colliculus recess Inferior colliculus Optic chiasm Tectal (quadrigeminal) plate Tuber cinereum Cerebellum Hypophysis (pituitary gland) Superior medullary velum Mammillary body 4th ventricle and choroid plexus Cerebral peduncle Inferior medullary velum Cerebral aqueduct Pons Medulla oblongata (Sylvius) Genu Medial surface of cerebral of Rostrum hemisphere: brainstem excised corpus callosum Trunk Splenium Cingulate gyrus Isthmus of cingulate gyrus Mammillothalamic fasciculus Parietooccipital sulcus Mammillary body Cuneus Uncus Calcarine sulcus Optic nerve (II) Lingual gyrus Olfactory tract Crus Collateral sulcus of fornix Body Rhinal sulcus Column Medial occipitotemporal gyrus Fimbria of hippocampus Occipitotemporal sulcus Dentate gyrus Lateral occipitotemporal gyrus Parahippocampal gyrus 2
  • 7. NEUROANATOMY Cerebrum: Inferior View Sectioned brainstem Longitudinal cerebral fissure Frontal pole of cerebrum Genu of corpus callosum Straight gyrus Lamina terminalis Olfactory sulcus Olfactory bulb Orbital sulci Olfactory tract Orbital gyri Optic chiasm Temporal pole Optic nerve (II) (cut) Lateral sulcus (Sylvius) Hypophysis Inferior temporal sulcus (pituitary gland) Inferior temporal gyrus Anterior perforated substance Optic tract Tuber cinereum Mammillary body Inferior (infero- lateral) margin of cerebrum Posterior perforated substance (in interpeduncular fossa) Rhinal sulcus Cerebral crus Uncus Lateral geniculate body Inferior temporal gyrus Substantia nigra Medial geniculate Occipitotemporal body sulcus Red nucleus Lateral occipito- Pulvinar of thalamus temporal gyrus Superior colliculus (of corpora quadrigemina) Collateral sulcus Cerebral aqueduct Parahippocampal gyrus Splenium of corpus callosum Medial occipitotemporal gyrus Apex of cuneus Occipital pole of cerebrum Calcarine sulcus Longitudinal cerebral fissure Isthmus of cingulate gyrus 3
  • 8. NEUROANATOMY Basal Nuclei (Ganglia) Horizontal sections A B through cerebrum Genu of corpus callosum Head of caudate nucleus Lateral ventricle Anterior limb of internal Genu capsule Septum pellucidum Posterior limb Column of fornix Putamen Lentiform nucleus Globus pallidus Insula (island of Reil) 3rd ventricle Interthalamic adhesion External capsule Thalamus Claustrum Crus of fornix Retrolenticular part of internal capsule Choroid plexus Tail of caudate nucleus of lateral ventricle Hippocampus and fimbria Splenium of corpus callosum Occipital (posterior) horn of lateral ventricle Habenula Organization of Pineal body basal nuclei (ganglia) A B Caudate Putamen Globus nucleus pallidus Cleft for internal capsule Lentiform nucleus Striatum Body Caudate Thalamus nucleus Head Corpus striatum Levels of A A sections B B above Basal nuclei (ganglia) Pulvinar Lentiform nucleus Medial geniculate body (globus pallidus medial Lateral geniculate body to putamen) Amygdaloid body Tail of caudate nucleus Interrelationship of thalamus, lentiform nucleus, caudate nucleus and amygdaloid body (schema): left lateral view 4
  • 9. NEUROANATOMY Thalamus Corpus callosum (cut) Interventricular foramen (Monro) Head of caudate nucleus Tela choroidea (cut edge) of 3rd ventricle Septum pellucidum 3rd ventricle Columns of fornix Choroid plexus Anterior tubercle Superior thalamostriate vein Stria terminalis Pes hippocampi Interthalamic adhesion Temporal (inferior) horn of lateral ventricle Lamina affixa Internal cerebral vein Stria medullaris Dentate gyrus Habenular trigone Collateral eminence Pulvinar (retracted) Hippocampus Lateral geniculate body Fimbria of hippocampus Medial geniculate body Posterior commissure Brachium of superior colliculus Habenular commissure Brachium of inferior colliculus Pineal body Collateral trigone Superior colliculus Calcar avis Inferior colliculus Occipital (posterior) horn Cerebellum of lateral ventricle Calcarine sulcus 3rd ventricle Internal Interthalamic medullary adhesion lamina r Pulvinar rio a te n in dia An m Me ial La d na Me llar y lami Intralaminar MD VA edu D nuclei L LP al m rn Inte LP VL 3rd ventricle M VP VPL VI Reticular nucleus M CM VP M L VP VP Pulvinar Thalamic nuclei External Lateral geniculate body medullary CM Centromedian Medial geniculate body lamina LD Lateral dorsal LP Lateral posterior Median nuclei Schematic representation of thalamus M Medial MD Medial dorsal (external medullary lamina and Schematic section reticular nuclei removed) VA Ventral anterior through thalamus VI Ventral intermedial (at level of broken VL Ventral lateral Lateral nuclei line shown in figure VP Ventral posterior Medial nuclei at right) VPL Ventral posterolateral Anterior nuclei VPM Ventral posteromedial 5
  • 10. NEUROANATOMY Cerebellum Superior surface Anterior cerebellar notch Anterior lobe Quadrangular lobule (H IV-V) Central lobule (II & III) Primary fissure Horizontal fissure Culmen (IV & V) Simple lobule (H VI) Superior vermis Posterior lobe Declive (VI) Postlunate fissure Folium (VII A) Superior semilunar (anseriform) lobule (H VII A) Horizontal fissure Inferior semilunar Posterior cerebellar notch (caudal) lobule (H VII B) Anterior lobe Central lobule Inferior surface Superior vermis Wing of central lobule Lingula (I) Superior Middle Superior medullary velum Cerebellar peduncles Inferior Flocculus (H X) Flocculonodular lobe 4th ventricle Posterolateral (dorsolateral) Inferior medullary velum fissure Retrotonsillar fissure Nodule (X) Posterior lobe Uvula (IX) Inferior Tonsil vermis Pyramid (VIII) Biventer lobule (H VIII) Tuber (VII B) Secondary (postpyramidal) fissure Posterior cerebellar notch Horizontal fissure Inferior semilunar (caudal) lobule (H VII B) Cerebral crus Decussation of superior cerebellar peduncles Medial longitudinal fasciculus 4th ventricle Nuclear layer of medulla oblongata Superior medullary velum Fastigial Superior cerebellar peduncle Globose Cerebellar Lingula (I) nuclei Dentate Vermis Emboliform Section in plane of superior cerebellar peduncle 6
  • 11. NEUROANATOMY Brainstem Thalamus (cut surface) Posterolateral view Lateral geniculate body Optic tract Pulvinars of thalami Pineal body Medial geniculate body Superior colliculi Brachia of superior and inferior colliculi Inferior colliculi Cerebral crus Trochlear nerve (IV) Pons Superior medullary velum Trigeminal nerve (V) Superior cerebellar peduncle Middle cerebellar peduncle Rhomboid fossa of Vestibulocochlear nerve (VIII) 4th ventricle Facial nerve (VII) Glossopharyngeal (IX) and vagus (X) nerves Inferior cerebellar peduncle Cuneate tubercle Hypoglossal nerve (XII) Gracile tubercle Accessory nerve (XI) Dorsal roots of 1st spinal nerve (C1) Cuneate fasciculus Gracile fasciculus Olfactory tract Anterior perforated substance Anterior view Infundibulum (pituitary stalk) Optic chiasm Mammillary bodies Temporal lobe (cut surface) Optic tract Oculomotor nerve (III) Tuber cinereum Trochlear nerve (IV) Cerebral crus Trigeminal nerve (V) Abducent nerve (VI) Lateral geniculate body Facial nerve (VII) and intermediate nerve Posterior perforated substance Vestibulocochlear nerve (VIII) Pons Flocculus of cerebellum Middle cerebellar peduncle Choroid plexus of 4th ventricle Olive Glossopharyngeal nerve (IX) Pyramid Vagus nerve (X) Hypoglossal nerve (XII) Ventral roots of 1st spinal nerve (C1) Accessory nerve (XI) Decussation of pyramids 7
  • 12. NEUROANATOMY Fourth Ventricle and Cerebellum Habenular trigone Posterior view Medial Geniculate bodies 3rd ventricle Lateral Dorsal median sulcus Pulvinar of thalamus Superior cerebellar peduncle Pineal body Locus ceruleus Superior colliculus Medial eminence Inferior colliculus Facial colliculus Trochlear nerve (IV) Vestibular area Superior medullary velum Dentate nucleus Superior of cerebellum Middle Cerebellar peduncles Inferior Striae medullares Lateral recess Tenia of 4th ventricle Superior fovea Cuneate tubercle Sulcus limitans Gracile tubercle Inferior fovea Dorsal median sulcus Trigeminal tubercle Lateral funiculus Hypoglossal trigone Cuneate fasciculus Vagal trigone Gracile fasciculus Obex Interthalamic adhesion Median sagittal section Posterior commissure Body of fornix Habenular commissure Thalamus (in Pineal body 3rd ventricle) Interventricular Splenium of corpus callosum foramen (Monro) Great cerebral vein (Galen) Anterior commissure Lamina terminalis Lingula (I) Hypothalamic sulcus Central lobule (II-III) Vermis of Cerebral peduncle Culmen (IV-V) cerebellum Declive (VI) Cerebral aqueduct (Sylvius) Folium (VII A) Superior colliculus Tectal (quadrigeminal) plate Superior medullary velum Inferior colliculus Inferior medullary velum Pons Medial longitudinal fasciculus Tuber (VII B) 4th ventricle Pyramid (VIII) Vermis of Choroid plexus of 4th ventricle cerebellum Uvula (IX) Medulla oblongata Nodulus (X) Median aperture (foramen of Magendie) Choroid plexus of 4th ventricle Decussation of pyramids Central canal of spinal cord Tonsil of cerebellum 8
  • 13. NEUROANATOMY Accessory Nerve (XI): Schema Nucleus ambiguus Cranial root of accessory nerve (joins vagus nerve and via recurrent laryngeal nerve supplies muscles of Vagus nerve (X) larynx, except cricothyroid)* Spinal root of accessory nerve Jugular foramen Foramen magnum Superior ganglion of vagus nerve Accessory nerve (XI)* Inferior ganglion of vagus nerve C1 spinal nerve C2 spinal nerve Accessory nerve (to sternocleidomastoid and trapezius muscles) Sternocleidomastoid muscle (cut) C3 spinal nerve C4 spinal nerve Trapezius muscle Efferent fibers Proprioceptive fibers *Recent evidence suggests that the accessory nerve lacks a cranial root and has no connection to the vagus nerve. Verification of this finding awaits further investigation. 9
  • 14. NEUROANATOMY Arteries to Brain and Meninges Left middle meningeal artery Middle cerebral artery Posterior cerebral artery Anterior cerebral artery Superior cerebellar artery Anterior communicating artery Basilar artery Ophthalmic artery Left labyrinthine (internal acoustic) artery Posterior communicating artery Mastoid branch of left occipital artery Cavernous sinus Anterior inferior cerebellar artery Middle meningeal artery Posterior meningeal branch of left ascending pharyngeal artery Posterior inferior cerebellar artery Left and right Maxillary vertebral arteries artery (intracranial part) Superficial temporal Posterior meningeal artery branch of vertebral artery External carotid Anterior meningeal artery branch of vertebral artery Posterior auricular artery Facial artery Occipital artery Lingual artery Internal carotid artery Ascending pharyngeal artery Carotid sinus Superior laryngeal artery Carotid body Superior thyroid artery Vertebral artery Common carotid artery (cervical part) Transverse process of C6 Ascending cervical artery (cut) Deep cervical artery Inferior thyroid artery Supreme intercostal Thyrocervical trunk artery Brachiocephalic trunk Costocervical trunk Internal thoracic artery Subclavian artery 10
  • 15. NEUROANATOMY Arteries to Brain: Schema Anterior communicating artery Anterior cerebral artery 1 Ophthalmic artery Middle cerebral artery Supraorbital artery Posterior communicating artery Supratrochlear artery 2 Caroticotympanic branch 3 3 Lacrimal artery of internal carotid artery 3 1 Dorsal nasal artery Posterior cerebral artery Middle meningeal artery 3 Superior cerebellar artery Angular artery Anterior tympanic artery Superficial temporal artery 1 1 Middle meningeal artery Posterior auricular artery 4 Facial artery Maxillary artery 5 5 Occipital artery Basilar artery 4 Lingual artery Anterior inferior cerebellar artery 5 5 Ascending pharyngeal artery Anterior spinal artery Posterior inferior 5 cerebellar artery Spinal segmental medullary branches External carotid artery 5 Vertebral artery 5 Internal carotid artery Common carotid artery Superior thyroid artery Deep cervical artery 5 Transverse cervical artery Common carotid artery Suprascapular artery Vertebral artery Supreme intercostal artery Ascending cervical artery Costocervical trunk Inferior thyroid artery Thyrocervical trunk Subclavian artery Subclavian artery Internal thoracic artery Brachiocephalic trunk Anastomoses Arch 1 Right–Left Aorta Descending 2 Carotid–Vertebral 3 Internal carotid–External carotid Ascending 4 Subclavian–Carotid 5 Subclavian–Vertebral 11
  • 16. NEUROANATOMY Arteries of Brain: Inferior Views Medial frontobasal (orbitofrontal) artery Anterior communicating artery Anterior cerebral artery Distal medial striate artery (recurrent artery of Heubner) Internal carotid artery Anterolateral central (lenticulostriate) arteries Middle cerebral artery Lateral frontobasal (orbitofrontal) artery Prefrontal artery Anterior choroidal artery Posterior communicating artery Posterior cerebral artery Superior cerebellar artery Basilar artery Pontine arteries Labyrinthine (internal acoustic) artery Anterior inferior cerebellar artery Vertebral artery Anterior spinal artery Posterior inferior cerebellar artery (PICA) (cut) Posterior spinal artery Cerebral arterial circle (Willis) (broken line) Distal medial striate artery (recurrent artery of Heubner) Anterior communicating artery Anterior cerebral artery Middle cerebral artery Posterior communicating artery Anterior choroidal artery Optic tract Posterior cerebral artery Cerebral crus Lateral geniculate body Posterior medial choroidal artery Posterior lateral choroidal artery Choroid plexus of lateral ventricle Medial geniculate body Pulvinar of thalamus Lateral ventricle 12
  • 17. NEUROANATOMY Cerebral Arterial Circle (Willis) Distal medial striate artery Vessels dissected out: inferior view (recurrent artery of Heubner) Anterior cerebral artery Anteromedial central (perforating) (A2 segment) arteries Anterior communicating artery Hypothalamic artery Anterior cerebral artery (A1 segment) Anterolateral central (lenticulostriate) arteries Ophthalmic artery Internal carotid artery Middle cerebral artery Superior hypophyseal artery Posterior communicating artery Inferior hypophyseal artery Anterior choroidal artery Posterior cerebral artery (P2 segment) Thalamotuberal (P1 segment) (premammillary) artery Posteromedial central Superior cerebellar artery (perforating) arteries Thalamoperforating artery Basilar artery Posteromedial central Pontine arteries (paramedian) arteries Anterior inferior cerebellar artery Labyrinthine (internal acoustic) artery Vertebral artery Vessels in situ: inferior view Anterior communicating artery Anterior cerebral artery Optic chiasm Hypothalamic artery Cavernous sinus Internal carotid artery Infundibulum (pituitary stalk) and long hypophyseal portal veins Superior hypophyseal artery Adenohypophysis (anterior Middle cerebral artery lobe of pituitary gland) Neurohypophysis (posterior Inferior hypophyseal artery lobe of pituitary gland) Posterior communicating artery Posteromedial central (perforating) arteries Efferent hypophyseal veins Superior cerebellar artery Posterior cerebral artery Basilar artery 13
  • 18. NEUROANATOMY Arteries of Brain: Frontal View and Section Paracentral artery Corpus callosum Medial frontal branches Anterolateral central (lenticulostriate) arteries Pericallosal artery Lateral frontobasal Callosomarginal artery (orbitofrontal) artery Polar frontal artery Prefrontal artery Anterior cerebral arteries Precentral (pre-rolandic) and central (rolandic) Medial frontobasal sulcal arteries (orbitofrontal) artery Anterior parietal Distal medial striate (postcentral sulcal) artery (recurrent artery artery of Heubner) Posterior parietal Internal carotid artery artery Branch to Anterior choroidal angular gyrus artery Temporal branches Posterior cerebral (anterior, middle artery and posterior) Superior cerebellar artery Middle cerebral artery Basilar and pontine arteries and branches (deep in lateral cerebral Labyrinthine (internal [sylvian] sulcus) acoustic) artery Anterior communicating artery Vertebral artery Posterior communicating artery Posterior inferior cerebellar artery Anterior inferior cerebellar artery Anterior spinal artery Posterior spinal artery Falx cerebri Callosomarginal arteries Corpus striatum and (caudate and lentiform nuclei) Pericallosal arteries (branches of anterior Anterolateral central cerebral arteries) (lenticulostriate) arteries Insula (island of Reil) Trunk of corpus callosum Limen of insula Internal capsule Precentral (pre-rolandic), Septum pellucidum central (rolandic) sulcal and parietal arteries Rostrum of corpus callosum Lateral cerebral (sylvian) sulcus Anterior cerebral arteries Temporal branches of middle cerebral artery Distal medial striate artery (recurrent artery of Heubner) Temporal lobe Anterior communicating artery Middle cerebral artery Optic chiasm Internal carotid artery 14
  • 19. NEUROANATOMY Arteries of Brain: Lateral and Medial Views Anterior parietal (postcentral sulcal) artery Posterior parietal artery Central (rolandic) sulcal artery Branch to angular gyrus Precentral (pre-rolandic) sulcal artery Terminal branches of posterior Prefrontal sulcal cerebral artery artery Terminal branches of anterior cerebral artery Lateral frontobasal (orbitofrontal) artery Left middle cerebral artery Left anterior cerebral artery Occipitotemporal Anterior communicating artery branches Posterior temporal branch Right anterior cerebral artery Middle temporal branch Left internal carotid artery Superior and inferior terminal branches (trunks) Anterior temporal branch Polar temporal artery Paracentral artery Pericallosal artery Posterior Medial Cingular branches frontal Intermediate branches Right posterior cerebral artery Anterior Precuneal artery Callosomarginal Dorsal branch artery to corpus callosum Parietooccipital branch Polar frontal artery Calcarine branch Right anterior cerebral artery Medial fronto- basal (orbito- frontal) artery Anterior communicating artery (cut) Medial occipital artery Distal medial striate artery Posterior temporal branch (recurrent artery of Heubner) Anterior temporal branch Right internal carotid artery Posterior communicating artery Note: Anterior parietal (postcentral sulcal) artery also occurs as separate anterior parietal and postcentral sulcal arteries 15
  • 20. NEUROANATOMY Arteries of Posterior Cranial Fossa Thalamogeniculate arteries Lateral and medial geniculate bodies of left thalamus Choroid plexuses of lateral ventricles Anterior choroidal artery Pulvinars of left and right thalami Crura of fornix Splenium of corpus callosum Anterolateral central (lenticulostriate) arteries Occipital (posterior) horn of right lateral ventricle Right dorsal branch to corpus callosum Heads of caudate nuclei (posterior pericallosal artery) Septum pellucidum Branches of Parietooccipital right posterior Corpus callosum Calcarine cerebral artery Anterior cerebral arteries Longitudinal cerebral fissure Superior colliculi Superior vermian Optic nerve (II) branch IV Ophthalmic artery Posterior medial III V choroidal artery Anterior to choroid plexus cerebral artery of 3rd ventricle VIII Middle Posterior lateral cerebral artery choroidal artery VII Posterior VI communicating artery Lateral (marginal) branch IX Thalamoperforating arteries Inferior vermian artery X (phantom) Left internal carotid artery XI Basilar artery Choroidal branch to 4th ventricle (phantom) and Pontine arteries Cerebellar tonsillar branch of posterior inferior cerebellar artery Labyrinthine (internal acoustic) artery Outline of 4th ventricle (broken line) Posterior cerebral artery Superior cerebellar artery Posterior meningeal branch of vertebral artery Anterior inferior cerebellar artery Posterior inferior cerebellar artery (PICA) Anterior meningeal branch of vertebral artery Left posterior spinal artery Temporal branches of posterior cerebral artery Left vertebral artery Anterior spinal artery 16
  • 21. NEUROANATOMY Veins of Posterior Cranial Fossa Left pulvinar Left superior and inferior colliculi Right pulvinar Basal vein (Rosenthal) Internal cerebral veins Posterior mesencephalic vein Splenium of corpus callosum Medial geniculate body Great cerebral vein (Galen) Lateral mesencephalic vein Dorsal vein of corpus callosum Lateral geniculate body Inferior sagittal sinus Left thalamus Straight sinus (cut surface) Falx cerebri Confluence of sinuses Optic tract Tentorium Inferior thalamo- cerebelli (cut) Left transverse striate veins sinus (cut) Deep middle Superior cerebral sagittal vein (cut) sinus Anterior cerebral vein Optic nerve (II) C C CL D F L TU Superior vermian N P vein U Inferior vermian vein Falx cerebelli (cut) Anterior ponto- T and occipital sinus mesencephalic vein Inferior cerebellar Trigeminal nerve (V) hemispheric veins Transverse pontine vein Intraculminate vein Superior cerebellar vein (inconstant) Petrosal vein (draining to superior petrosal sinus) Preculminate vein Lateral pontine vein Precentral cerebellar vein Superior retrotonsillar vein Anteromedian medullary vein Parts of cerebellum (Inferior retrotonsillar) Vein of lateral recess of 4th ventricle vein of cerebellomedullary L Lingula TU Tuber cistern Superior, middle and CL Central lobule P Pyramid inferior cerebellar peduncles C Culmen U Uvula Posterior spinal vein D Declive N Nodule Anterior spinal vein 4th ventricle F Folium T Tonsil 17
  • 22. NEUROANATOMY Deep Veins of Brain Longitudinal cerebral fissure Anterior cerebral veins Rostrum of corpus callosum Septum pellucidum Anterior vein of septum pellucidum Head of caudate nucleus Anterior vein of caudate nucleus Transverse veins of caudate nucleus Interventricular foramen (Monro) Columns of fornix Superior thalamostriate vein Superior choroid vein and choroid plexus of lateral ventricle Thalamus Tela choroidea of 3rd ventricle Lateral direct vein Posterior vein of caudate nucleus Internal cerebral veins Basal vein (Rosenthal) Great cerebral vein (Galen) Inferior sagittal sinus Straight sinus Tentorium cerebelli Transverse sinus Confluence of sinuses Superior sagittal sinus Dissection: superior view Uncal vein Anterior cerebral vein Superficial middle cerebral vein (draining to sphenoparietal sinus) Optic chiasm Deep middle cerebral vein Cerebral crus Basal vein (Rosenthal) Inferior Lateral geniculate body cerebral veins Medial geniculate body Pulvinar of thalamus Splenium of corpus callosum Great cerebral vein (Galen) Inferior anastomotic vein (Labbé) Dissection: inferior view 18
  • 23. NEUROANATOMY Subependymal Veins of Brain Posterior veins of septum pellucidum Lateral direct vein Posterior terminal vein of caudate nucleus Superior thalamic veins (posterior part of thalamostriate vein) Superior choroid vein Internal cerebral veins (right and left) Transverse veins of caudate nucleus Medial (atrial) vein of lateral ventricle Superior thalamostriate vein Lateral (atrial) vein of lateral ventricle Lateral ventricle Splenium of corpus callosum Anterior vein of Great cerebral vein caudate nucleus (Galen) Anterior vein of Dorsal vein of corpus septum pellucidum callosum Genu of Inferior sagittal corpus sinus callosum Internal occipital vein Straight sinus Occipital (posterior) horn of lateral ventricle Interventricular foramen (Monro) Anterior commissure Interthalamic adhesion Anterior cerebral vein Optic chiasm Cerebellum 3rd ventricle Deep middle cerebral vein Inferior thalamostriate veins Basal vein (Rosenthal) Temporal (inferior) horn of lateral ventricle Posterior mesencephalic vein Superior vermian vein Hippocampal and inferior ventricular veins Cerebral aqueduct Veins on lateral wall of ventricle 4th ventricle Veins on medial wall and floor of ventricle All other veins Lateral and median apertures of 4th ventricle 19
  • 24. NEUROANATOMY Hypothalamus and Hypophysis Septum pellucidum Thalamus Fornix Hypothalamic sulcus Anterior commissure Paraventricular Posterior Dorsomedial Principal nuclei of Supraoptic hypothalamus Ventromedial Arcuate (infundibular) Mammillary Mammillothalamic tract Optic chiasm Dorsal longitudinal fasciculus and other Infundibulum (pituitary stalk) descending pathways Hypophysis (pituitary gland) Lamina terminalis Hypothalamic sulcus Paraventricular hypothalamic nucleus Supraoptic hypothalamic nucleus Supraopticohypophyseal tract Tuberohypophyseal tract Mammillary body Hypothalamohypophyseal tract Infundibulum (pituitary stalk) Arcuate (infundibular) nucleus Pars tuberalis Median eminence of tuber cinereum Fibrous trabecula Adenohypophysis (anterior lobe of Neurohypophysis Infundibular pituitary gland) Pars intermedia (posterior lobe stem of pituitary gland) Pars distalis Infundibular process Cleft 20
  • 25. NEUROANATOMY Arteries and Veins of Hypothalamus and Hypophysis Hypothalamic vessels Primary plexus of hypophyseal portal system Superior hypophyseal Long hypophyseal portal veins artery Artery of trabecula Short hypophyseal portal veins Trabecula (fibrous tissue) Efferent hypophyseal vein Efferent hypophyseal vein to cavernous sinus to cavernous sinus Secondary plexus Neurohypophysis of hypophyseal (posterior lobe of portal system pituitary gland) Capillary plexus of infundibular process Adenohypophysis (anterior lobe of pituitary gland) Efferent hypophyseal vein to cavernous sinus Inferior hypophyseal artery Efferent hypophyseal veins to cavernous sinus 21
  • 26. NEUROANATOMY Relation of Spinal Nerve Roots to Vertebrae L4 C1 spinal nerve exits C1 above C1 vertebra C1 Base C2 L4 of skull C2 C3 C3 Cervical C4 enlargement C4 L5 C5 C5 C6 C8 spinal nerve L5 C6 C7 exits below C7 vertebra C7 C8 (there are 8 cervical T1 nerves but only T1 7 cervical vertebrae) T2 T2 S1 T3 T3 T4 T4 S2 T5 T5 T6 T6 Lumbar disc protrusion does not usually affect T7 T7 nerve exiting above disc. Lateral protrusion T8 at disc level L4–5 affects L5 spinal nerve, not T8 L4 spinal nerve. Protrusion at disc level L5–S1 T9 affects S1 spinal nerve, not L5 spinal nerve T9 T10 T10 T11 T11 Lumbar enlargement T12 L4 T12 Conus medullaris L1 (termination of L4 L1 spinal cord) L2 L2 L5 L3 L5 L3 Cauda equina Internal terminal L4 filum (pial part) L4 S1 L5 L5 S2 Sacrum S1 S3 S2 External terminal filum S3 S4 (dural part) Termination of dural sac S4 S5 S5 Coccygeal nerve Coccyx Coccygeal nerve Cervical nerves Thoracic nerves Medial protrusion at disc level L4–5 rarely affects Lumbar nerves L4 spinal nerve but may affect L5 spinal nerve and sometimes S1–4 spinal nerves Sacral and coccygeal nerves 22
  • 27. NEUROANATOMY Autonomic Nervous System: General Topography Oculomotor nerve (III) Ciliary ganglion Facial nerve (VII) Pterygopalatine ganglion Glossopharyngeal nerve (IX) Otic ganglion Vagus nerve (X) Chorda tympani nerve Internal carotid nerve and plexus Lingual nerve Superior cervical sympathetic ganglion Submandibular ganglion C4 spinal nerve Pharyngeal and superior laryngeal branches of vagus nerve Middle cervical sympathetic ganglion Recurrent laryngeal branch of vagus nerve Vertebral ganglion Superior cervical Cardiac branches Cervicothoracic (stellate) ganglion Inferior cervical of vagus nerve Thoracic Sympathetic trunk Cardiac plexus Superior Cervical (sympathetic) Middle cardiac nerves Anterior Pulmonary plexuses Inferior Posterior Thoracic (sympathetic) cardiac nerves Esophageal plexus 6th intercostal nerve Thoracic aortic plexus (ventral ramus of T6 spinal nerve) Anterior vagal trunk Sympathetic trunk Posterior vagal trunk 6th thoracic sympathetic ganglion Celiac ganglion Gray and white rami communicantes Celiac trunk and plexus Greater splanchnic nerve Superior mesenteric ganglion Lesser splanchnic nerve Superior mesenteric artery and plexus Least splanchnic nerve Intermesenteric Aorticorenal ganglion (abdominal aortic) plexus Lumbar splanchnic nerves (sympathetic) Inferior mesenteric ganglion Gray rami communicantes Inferior mesenteric artery and plexus Sacral splanchnic nerves (sympathetic) Superior hypogastric plexus Pelvic splanchnic nerves (sacral parasympathetic Parasympathetic branch from outflow) inferior hypogastric plexus to descending colon Sciatic nerve Hypogastric nerves Inferior hypogastric (pelvic) plexus Rectal plexus Vesical plexus Sympathetic fibers Prostatic plexus Parasympathetic fibers 23
  • 28. NEUROANATOMY Spinal Nerve Origin: Cross Sections Section through thoracic vertebra Aorta Body of vertebra Fat in epidural space Dura mater Sympathetic ganglion Arachnoid mater* Ventral root Subarachnoid space White and gray rami Pia mater* communicantes Recurrent Spinal nerve meningeal branches of Ventral ramus spinal nerve (intercostal nerve) Dorsal ramus Pleura Lung Spinal sensory (dorsal root) ganglion Dorsal root Lateral horn of gray matter of spinal cord Section through lumbar vertebra of dorsal Lateral branch ramus Sympathetic of spinal Medial branch Dura mater ganglion nerve Internal vertebral Arachnoid mater Gray ramus (epidural) venous plexus communicans Ventral root Fat in Spinal nerve epidural space Ventral ramus (contributes to lumbar plexus) Dorsal ramus Spinal sensory (dorsal root) ganglion Dorsal and ventral roots of lumbar and Dorsal root sacral spinal nerves Conus medullaris forming cauda equina *Leptomeninges 24
  • 29. NEUROANATOMY Olfactory Nerve (I): Schema Subcallosal (parolfactory) area Septal area and nuclei Olfactory bulb cells: schema Fibers from Contralateral Efferent fibers to olfactory bulb Fibers to olfactory bulb Afferent fibers from bulb Anterior commissure to central connections and contralateral bulb Medial olfactory stria Granule cell (excited by and inhibiting to mitral and tufted cells) Mitral cell Recurrent process Tufted cell Periglomerular cell Glomerulus Olfactory nerve fibers Olfactory cells Olfactory tract Olfactory mucosa Olfactory trigone and olfactory tubercle Olfactory nerves (I) Lateral olfactory stria Uncus Olfactory bulb Lateral olfactory tract nucleus Hippocampal Cribriform plate of ethmoid bone fimbria Anterior perforated substance Anterior olfactory nucleus Dentate gyrus Amygdaloid body (phantom) Piriform lobe Parahippocampal gyrus 25
  • 30. NEUROANATOMY Optic Nerve (II) (Visual Pathway): Schema G Central darker G circle represents macular zone Overlapping Lighter shades A visual fields represent A monocular fields B B Each quadrant H H a different color Projection on Projection on R RC C right retina left retina P P Optic nerves (II) Choroid Choroid Optic chiasm Periphery Macula Structure of retina: schema Projection on right Projection on left A Amacrine cells dorsal lateral dorsal lateral geniculate nucleus B Bipolar cells geniculate nucleus Optic tracts C Cones G Ganglion cells H Horizontal cells Lateral P Pigment cells geniculate R Rods bodies Optic radiation Optic radiation Calcarine sulcus Calcarine sulcus Projection on left Projection on right occipital lobe occipital lobe 26
  • 31. NEUROANATOMY Oculomotor (III), Trochlear (IV) and Abducent (VI) Nerves: Schema Ciliary ganglion Long ciliary nerve Short ciliary nerves Posterior ethmoidal nerve Abducent nucleus Anterior ethmoidal nerve Sensory root of ciliary ganglion Trochlear nucleus Superior oblique muscle Sympathetic root of ciliary ganglion Levator palpebrae Oculomotor nucleus superioris muscle Superior division of oculomotor nerve Superior Accessory oculomotor rectus muscle (Edinger-Westphal) Frontal nerve (cut) nucleus (parasympathetic) Lacrimal nerve (cut) Trochlear nerve (IV) Nasociliary nerve Oculomotor nerve (III) Ophthalmic nerve (V1) Abducent Infraorbital nerve nerve (VI) Zygomatic nerve (cut) Pterygopalatine Mandibular nerve (V3) ganglion Inferior oblique muscle Internal carotid artery Inferior division of Ciliary muscle and nerve plexus oculomotor nerve Dilator muscle of pupil Maxillary nerve (V2) Medial rectus muscle Sphincter muscle of pupil Lateral rectus muscle and Inferior rectus muscle abducent nerve (turned back) Efferent fibers Cavernous plexus Parasympathetic root Afferent fibers of ciliary ganglion Sympathetic fibers Common tendinous ring Parasympathetic fibers 27
  • 32. NEUROANATOMY Trigeminal Nerve (V): Schema Trigeminal nerve (V) ganglion and nuclei Ophthalmic nerve (V1) Motor nucleus Efferent fibers Mesencephalic nucleus Tentorial (meningeal) branch Principal sensory nucleus Afferent fibers Spinal tract and nucleus Nasociliary nerve Proprioceptive fibers Parasympathetic fibers Lacrimal nerve Sympathetic fibers Sensory root of ciliary ganglion Frontal nerve Ciliary ganglion Posterior ethmoidal nerve Long ciliary nerve Short ciliary nerves Anterior ethmoidal nerve Supraorbital nerve Supratrochlear nerve Infratrochlear nerve Internal nasal branches and External nasal branches of anterior ethmoidal nerve Maxillary nerve (V2) Meningeal branch Zygomaticotemporal nerve Zygomaticofacial nerve Zygomatic nerve Infraorbital nerve Pterygopalatine ganglion Superior alveolar branches of infraorbital nerve Nasal branches (posterior superior Facial nerve (VII) lateral, nasopalatine and posterior Chorda superior medial) tympani nerve Nerve (vidian) of pterygoid canal (from facial nerve [VII] and carotid plexus) Pharyngeal branch Greater and lesser palatine nerves Superficial Deep temporal nerves temporal branches (to temporalis muscle) Articular branch Lateral pterygoid and anterior and masseteric nerves auricular nerves Tensor veli palatini and Auriculotemporal nerve medial pterygoid nerves Submandibular Inferior Buccal nerve Parotid branches ganglion alveolar nerve Mental nerve Meningeal branch Mylohyoid nerve Otic ganglion Inferior dental plexus Lesser petrosal nerve (from Mandibular nerve (V3) Tensor tympani nerve Lingual nerve glossopharyngeal nerve [IX]) 28
  • 33. NEUROANATOMY Facial Nerve (VII): Schema Facial nerve (VII) Internal acoustic meatus Greater petrosal nerve Geniculate ganglion Intermediate nerve Deep petrosal nerve (from internal carotid plexus) Motor nucleus of facial nerve Internal carotid plexus Lesser petrosal nerve (on internal carotid artery) Superior salivatory nucleus Nerve (vidian) of pterygoid canal Solitary tract nucleus Otic ganglion Pterygopalatine ganglion Facial muscles Frontal belly (frontalis) of occipitofrontalis Orbicularis oculi Corrugator supercilii Zygomaticus major Zygomaticus minor Temporal bran Procerus Levator labii superioris Levator labii superioris che alaeque nasi s Levator anguli oris Nasalis Zygomatic bra nch es Depressor Occipital anterior 2⁄3 septi nasi Taste: tongue belly of Buccal (occipitalis) of Orbicularis branches occipitofrontalis oris muscle Occipital Depressor h anc branch of anguli oris posterior al br auricular Depressor labii Cer vic nerve inferioris Branches to auricular muscles Mentalis Posterior auricular nerve (Risorius) al Margin ular (not shown) Nerve to stapedius muscle dib man branch Buccinator Stylomastoid foramen Tympanic plexus Platysma Tympanic nerve (Jacobson) Sublingual gland (from glossopharyngeal nerve) Submandibular gland Glossopharyngeal nerve (IX) Efferent fibers Submandibular ganglion Digastric muscle (posterior belly) Afferent fibers Lingual nerve (from trigeminal nerve) Stylohyoid muscle Parasympathetic fibers Sympathetic fibers Chorda tympani nerve Caroticotympanic nerve (from internal carotid plexus) 29
  • 34. NEUROANATOMY Vestibulocochlear Nerve (VIII): Schema Afferent fibers Facial canal Tympanic cavity Geniculum of facial nerve (site of geniculate ganglion) Chorda tympani nerve Greater petrosal nerve Head of malleus Cochlear (spiral) ganglion Incus Vestibular nerve Cochlear nerve Motor root of facial nerve and intermediate nerve Vestibulocochlear nerve (VIII) Medulla oblongata (cross section) Ampulla of lateral semicircular duct Internal acoustic Ampulla of superior Medial meatus semicircular duct Superior Vestibular Utricle Anterior nuclei Cochlear (diagrammatic) Inferior nuclei Posterior Ampulla of posterior semicircular duct Lateral Inferior cerebellar Saccule peduncle (to cerebellum) Superior division Vestibular ganglion of vestibular nerve Inferior division 30
  • 35. NEUROANATOMY Glossopharyngeal Nerve (IX): Schema Spinal tract and spinal nucleus of trigeminal nerve Efferent fibers Afferent fibers Solitary tract nucleus Parasympathetic fibers Tympanic nerve (Jacobson) Nucleus ambiguus Tympanic cavity and plexus Inferior salivatory nucleus Geniculate ganglion Stylomastoid foramen of facial nerve Caroticotympanic nerve (from internal carotid plexus) Greater petrosal nerve Deep petrosal nerve Nerve (vidian) of pterygoid canal Lesser petrosal nerve Pterygopalatine ganglion Mandibular nerve (V3) Otic ganglion Auriculotemporal nerve Parotid gland Tubal branch of tympanic plexus Pharyngotympanic (auditory) tube and pharyngeal opening Glossopharyngeal Stylopharyngeus muscle (and branch nerve (IX) from glossopharyngeal nerve) Jugular foramen Communication to auricular branch of vagus nerve Superior and Inferior ganglia of Glossopharyngeal nerve Communication to facial nerve (VII) Taste and somatic Vagus nerve (X) sensation: posterior Superior cervical ⁄3 of tongue 1 sympathetic ganglion Sympathetic trunk Carotid branch of glossopharyngeal nerve Internal carotid artery Pharyngeal plexus Carotid sinus Pharyngeal, tonsillar and lingual Carotid body branches of glossopharyngeal nerve Common carotid artery Pharyngeal branch of vagus nerve External carotid artery 31
  • 36. NEUROANATOMY Vagus Nerve (X): Schema Posterior nucleus of vagus nerve (parasympathetic SEE ALSO PLATE 160 and visceral afferent) Glossopharyngeal nerve (IX) Solitary tract nucleus (visceral Meningeal branch of vagus nerve afferents including taste) Auricular branch of vagus nerve Spinal tract and spinal nucleus of trigeminal nerve Pharyngotympanic (auditory) tube (somatic afferent) Levator veli Nucleus ambiguus palatini muscle (motor to pharyngeal and laryngeal muscles) Salpingopharyngeus muscle Cranial root of accessory nerve* Palatoglossus muscle (see next plate) Vagus nerve (X) Palatopharyngeus muscle Jugular foramen Superior pharyngeal Superior ganglion of vagus nerve constrictor muscle Inferior ganglion of vagus nerve Stylopharyngeus muscle Pharyngeal branch of vagus nerve (motor to muscles of Middle pharyngeal constrictor muscle palate and lower pharynx; sensory to lower pharynx) Inferior pharyngeal constrictor muscle Communicating branch of vagus nerve to carotid branch of glossopharyngeal nerve Cricothyroid muscle Trachea Pharyngeal plexus Esophagus Superior laryngeal nerve: Internal branch (sensory and parasympathetic) Right subclavian artery External branch (motor to cricothyroid muscle) Right recurrent laryngeal nerve Superior cervical cardiac branch of vagus nerve Heart Inferior cervical cardiac branch of vagus nerve Hepatic branch of anterior Thoracic cardiac branch of vagus nerve vagal trunk (in lesser omentum) Left recurrent laryngeal nerve (motor to muscles of larynx Celiac branches from anterior except cricothyroid; sensory and parasympathetic to and posterior vagal trunks larynx below vocal folds; parasympathetic, efferent and to celiac plexus afferent to upper esophagus and trachea) Celiac and superior mesenteric Pulmonary plexus ganglia and celiac plexus Cardiac plexus Hepatic plexus Esophageal plexus Gallbladder and bile ducts Anterior vagal trunk Liver Gastric branches of anterior vagal trunk (branches from posterior trunk behind stomach) Pyloric branch from hepatic plexus Vagal branches (parasympathetic motor, secretomotor and afferent fibers) accompany Pancreas superior mesenteric artery and its branches usually as far as left colic (splenic) flexure Duodenum Small intestine Ascending colon Efferent fibers Cecum Afferent fibers Appendix Parasympathetic fibers 32
  • 37. NEUROANATOMY Accessory Nerve (XI): Schema SEE ALSO PLATE 28 Nucleus ambiguus Cranial root of accessory nerve (joins vagus nerve and via recurrent laryngeal nerve supplies muscles of Vagus nerve (X) larynx, except cricothyroid)* Spinal root of accessory nerve Jugular foramen Foramen magnum Superior ganglion of vagus nerve Accessory nerve (XI)* Inferior ganglion of vagus nerve C1 spinal nerve C2 spinal nerve Accessory nerve (to sternocleidomastoid and trapezius muscles) Sternocleidomastoid muscle (cut) C3 spinal nerve C4 spinal nerve Trapezius muscle Efferent fibers Proprioceptive fibers *Recent evidence suggests that the accessory nerve lacks a cranial root and has no connection to the vagus nerve. Verification of this finding awaits further investigation. 33
  • 38. NEUROANATOMY Hypoglossal Nerve (XII): Schema Meningeal branch Hypoglossal nerve (XII) (in hypoglossal canal) Hypoglossal nucleus Superior longitudinal Intrinsic muscles Transverse of tongue and vertical Styloglossus muscle Inferior longitudinal Occipital condyle Inferior ganglion of vagus nerve Ventral rami of C1, 2, 3 form ansa cervicalis of cervical plexus Superior cervical sympathetic ganglion Superior root of Genioglossus ansa cervicalis muscle Internal carotid artery Geniohyoid muscle Inferior root of ansa cervicalis Hyoglossus muscle Thyrohyoid muscle Ansa cervicalis Omohyoid muscle Internal jugular vein (superior belly) Common carotid artery Sternohyoid muscle Sternothyroid muscle Omohyoid muscle (inferior belly) Efferent fibers Afferent fibers 34
  • 39. NEUROANATOMY Nerves of Heart Superior cervical Superior cervical sympathetic ganglion sympathetic ganglion Vagus nerve (X) Vagus nerve (X) Superior cervical (Conjoined sympathetic and (sympathetic) cardiac nerve vagal) superior cervical cardiac nerves Superior cervical Middle cervical (vagal) cardiac nerve sympathetic ganglion Middle cervical Middle cervical sympathetic ganglion (sympathetic) cardiac nerve Phrenic nerve Phrenic nerve Middle cervical Inferior cervical (sympathetic) cardiac nerve (vagal) cardiac nerve Inferior cervical Vertebral ganglion (vagal) cardiac nerve Inferior thyroid artery Vertebral ganglion Vertebral artery Cervicothoracic (stellate) ganglion Cervicothoracic (stellate) ganglion Inferior cervical sympathetic Ansa subclavia cardiac nerves Recurrent laryngeal nerve 3rd thoracic Inferior cervical sympathetic ganglion (sympathetic) cardiac nerves Thoracic cardiac branch Thoracic (sympathetic) of vagus nerve cardiac branches 4th thoracic Thoracic cardiac sympathetic ganglion branch of vagus nerve Thoracic (sympathetic) cardiac branches Recurrent laryngeal nerve Cardiac plexus Phrenic nerve (cut) 35
  • 40. NEUROANATOMY Autonomic Nerves and Ganglia of Abdomen Right sympathetic trunk Anterior, Posterior Thoracic duct vagal trunks Right greater Left gastric artery and lesser and plexus splanchnic Celiac ganglia nerves Left greater Right phrenic nerve splanchnic nerve Inferior phrenic Left lesser arteries and plexuses splanchnic nerve Right greater Splenic artery and lesser and plexus splanchnic Common hepatic nerves artery and plexus Right suprarenal Superior mesenteric plexus ganglion and plexus Right aortico- Left aorticorenal renal ganglion ganglion Right least Left sympathetic splanchnic nerve trunk Right renal Intermesenteric artery and plexus (aortic) plexus Inferior mesenteric Right ganglion sympathetic trunk Left colic artery White and gray and plexus rami communicantes Inferior mesenteric Cisterna chyli artery and plexus Gray ramus communicans Left common iliac artery and plexus 3rd lumbar ganglion Superior rectal of sympathetic trunk artery and plexus 2nd and 3rd lumbar Superior hypogastric splanchnic nerves plexus Right ureter and plexus Internal and external iliac arteries and Right testicular (ovarian) plexuses artery and plexus Right and left 4th lumbar splanchnic nerve hypogastric nerves to inferior hypo- 1st sacral ganglion gastric (pelvic) plexus of sympathetic trunk Left sacral plexus Gray rami communicantes Pelvic splanchnic nerves 36
  • 41. NEUROANATOMY Nerves of Stomach and Duodenum Right and left inferior phrenic arteries and plexuses Hepatic branch of anterior vagal trunk Anterior and posterior layers of lesser omentum Anterior vagal trunk Branch from hepatic plexus to Celiac branch of posterior vagal trunk cardia via lesser omentum Celiac branch of anterior vagal trunk Right greater splanchnic nerve Left gastric artery and plexus Vagal branch from hepatic plexus to pyloric part of stomach Hepatic plexus Right gastric artery and plexus Anterior gastric branch of anterior vagal trunk Left greater splanchnic nerve Left lesser splanchnic nerve Splenic artery and plexus Celiac ganglia and plexus Plexus on gastro-omental (gastroepiploic) arteries Superior mesenteric artery and plexus Plexus on inferior pancreaticoduodenal artery Plexus on first jejunal artery Plexus on anterior superior and anterior inferior pancreaticoduodenal arteries (posterior pancreaticoduodenal arteries and plexuses not visible in this view) 37
  • 42. NEUROANATOMY Nerves of Stomach and Duodenum (continued) Posterior gastric branch of posterior vagal trunk Plexus on gastro-omental (gastroepiploic) arteries Hepatic branch of anterior vagal trunk via lesser omentum Hepatic plexus Branch from hepatic plexus to cardia via lesser omentum Right gastric artery and Right inferior phrenic artery and plexus plexus Posterior vagal trunk Celiac branch of posterior vagal trunk Celiac branch of anterior vagal trunk Left gastric artery and plexus Left inferior phrenic artery and plexus Celiac ganglia and plexus Greater, lesser and least splanchnic nerves Aorticorenal ganglia Splenic artery and plexus Right phrenic nerve Phrenic ganglion Greater, Lesser, Branch from right inferior phrenic Least plexus to cardia of stomach splanchnic Right and left inferior phrenic nerves arteries and plexuses Anterior vagal trunk Posterior vagal trunk View with stomach reflected cephalad Plexus on anterior superior and anterior inferior pancreatico- Celiac branches duodenal arteries of anterior Right greater, and posterior lesser Plexus on gastroduodenal artery vagal trunks and least splanchnic nerves Plexus on posterior superior Left gastric and posterior inferior artery and plexus Celiac ganglia pancreaticoduodenal arteries Left greater, Right aortico- Superior mesenteric ganglion and plexus lesser and least renal ganglion splanchnic nerves Left aorticorenal ganglion Superior mesenteric ganglion and plexus 38
  • 43. NEUROANATOMY Nerves of Small Intestine Recurrent branch of left inferior phrenic artery and plexus to esophagus Anterior vagal trunk Posterior vagal trunk Hepatic branch of anterior vagal trunk (courses in lesser omentum, removed here) Celiac branches of anterior and posterior vagal trunks Inferior phrenic arteries and plexuses Left gastric artery and plexus Hepatic plexus Greater splanchnic nerves Right gastric artery and plexus (cut) Celiac ganglia and plexus Gastroduodenal artery and plexus Lesser splanchnic nerves Least splanchnic nerves Aorticorenal ganglia Superior mesenteric ganglion Intermesenteric (aortic) plexus Inferior pancreaticoduodenal arteries and plexuses Superior mesenteric artery and plexus Middle colic artery and plexus (cut) Right colic artery and plexus Ileocolic artery and plexus Superior mesenteric artery and plexus Peritoneum (cut edge) Mesenteric branches Mesoappendix (contains appendicular artery and nerve plexus) 39
  • 44. NEUROANATOMY Nerves of Large Intestine Anterior vagal trunk and hepatic branch Marginal artery and plexus Esophagus Posterior vagal trunk Left inferior phrenic Celiac branches of anterior artery and plexus and posterior vagal trunks Left gastric artery Right inferior phrenic artery and plexus and plexus Right greater Left greater splanchnic nerve splanchnic nerve Celiac ganglia and plexus Left suprarenal Right lesser and plexus least splanchnic nerves Left lesser and least splanchnic Right aortico- nerves renal ganglion Left aorticorenal Superior ganglion mesenteric ganglion Left renal artery and plexus Middle colic artery 1st left lumbar and plexus splanchnic nerve Inferior Left lumbar pancreatico- sympathetic trunk duodenal arteries Intermesenteric and plexuses (aortic) plexus Right colic Left colic artery artery and plexus and plexus Inferior Ileocolic mesenteric artery ganglion, artery and plexus and plexus Sigmoid Cecal and arteries appendicular and plexuses arteries and plexuses Superior hypogastric Right internal plexus iliac artery and plexus (cut) Superior rectal Sacral sympathetic trunk artery and plexus Right sacral plexus Right and left Pelvic splanchnic nerves hypogastric nerves Middle rectal artery and plexus Rectosigmoid Right inferior hypogastric artery and (pelvic) plexus plexus Vesical plexus Nerves from inferior hypogastric (pelvic) plexuses to sigmoid colon, descending Rectal plexus colon and left colic (splenic) flexure Urinary bladder 40
  • 45. NEUROANATOMY Nerves of Kidneys, Ureters and Urinary Bladder Anterior vagal trunk Posterior vagal trunk Greater splanchnic nerve Celiac ganglia and plexus Lesser splanchnic nerve Superior mesenteric ganglion Least splanchnic nerve Aorticorenal ganglion Renal plexus and ganglion 2nd lumbar splanchnic nerve Renal and upper ureteric branches from intermesenteric plexus Intermesenteric (aortic) plexus Testicular (ovarian) artery and plexus Inferior mesenteric ganglion Sympathetic trunk and ganglion Middle ureteric branch Superior hypogastric plexus Sacral splanchnic nerves (branches from upper sacral sympathetic ganglia to hypogastric plexus) Gray ramus communicans Hypogastric nerves Sacral plexus Pudendal nerve Pelvic splanchnic nerves Inferior hypogastric (pelvic) plexus with periureteric loops and branches to lower ureter Rectal plexus Vesical plexus Prostatic plexus 41
  • 46. NEUROANATOMY Nerves of Pelvic Viscera: Male Anterior vagal trunk T10 spinal nerve (anterior ramus) Posterior vagal trunk White and gray rami communicantes and Celiac branch Greater Splanchnic Lesser nerves Inferior phrenic arteries and plexuses Least Left gastric artery and gastric plexus Diaphragm Celiac ganglia, plexus and trunk Left renal artery and plexus Left aorticorenal ganglion L1 spinal nerve Superior mesenteric ganglion (anterior ramus) Superior mesenteric artery and plexus Gray Rami communicantes White Intermesenteric (aortic) plexus 1st, 2nd, 3rd lumbar splanchnic nerves Inferior mesenteric ganglion, artery and plexus Gray rami communicantes Ureter and ureteric plexus Sympathetic trunk and ganglia Superior hypogastric plexus 5th lumbar splanchnic nerve Superior rectal artery and plexus L5 spinal nerve (anterior ramus) Hypogastric nerves Lumbosacral trunk Nerve from inferior hypogastric plexus Gray rami communicantes to sigmoid and descending colon (parasympathetic) S1 spinal nerve (anterior ramus) Sacral splanchnic nerves (sympathetic) Pelvic splanchnic nerves Inferior hypogastric (parasympathetic) (pelvic) plexus Sacral plexus Obturator nerve and artery Piriformis muscle Ductus deferens Gluteus maximus and plexus muscle and sacro - tuberous ligament Vesical plexus Rectal plexus (Ischio-)coccygeus muscle and Prostatic plexus sacrospinous ligament Cavernous nerves Pudendal nerve of penis Levator ani muscle Inferior anal (rectal) nerve Perineal nerve Dorsal nerve of penis Posterior scrotal nerves 42
  • 47. NEUROANATOMY Nerves of Pelvic Viscera: Female Peritoneum Abdominal aorta Sympathetic trunk and L2 ganglion Inferior vena cava Extraperitoneal (subserous) White and fascia gray rami communicantes Common iliac vessels and plexus Lumbar Ureter splanchnic nerves Intermesenteric (aortic) plexus Ovarian artery Gray rami and plexus communicantes Superior hypogastric plexus L5 spinal nerve Sacral promontory Superior Right hypogastric hypogastric plexus nerve (cut) Common iliac artery and plexus Right and left sacral Ureter sympathetic Internal trunks and iliac artery ganglia Sigmoid and plexus colon External Right and left S1 Piriformis iliac artery hypogastric nerves muscle and plexus S2 Uterus Right sympathetic trunk S3 Sacral splanchnic nerves Left hypogastric nerve S4 (sympathetic) Inferior hypogastric (pelvic) plexus S5 Pudendal Uterine (fallopian) tube nerve Ovary Pelvic Symphyseal surface of pubis splanchnic nerves Urinary bladder (parasympathetic) Vesical plexus (Ischio-)coccygeus muscle Uterovaginal plexus Uterus (retracted) Rectal plexus Rectum (retracted) 43
  • 48. NEUROANATOMY Median Nerve Anterior view Note: Only muscles innervated by median nerve shown Musculocutaneous nerve Median nerve (C5, 6, 7, 8, T1) Medial Cords of Inconstant contribution Posterior brachial Lateral plexus Pronator teres muscle (humeral head) Medial cutaneous nerve of arm Articular branch Medial cutaneous nerve of forearm Flexor carpi radialis muscle Axillary nerve Palmaris longus muscle Radial nerve Pronator teres muscle (ulnar head) Ulnar nerve Flexor digitorum superficialis muscle (turned up) Flexor digitorum profundus muscle (lateral part supplied by median [anterior interosseous] nerve; medial part supplied by ulnar nerve) Anterior interosseous nerve Flexor pollicis longus muscle Pronator quadratus muscle Cutaneous Palmar branch of median nerve innervation Abductor pollicis brevis Opponens pollicis Superficial head of Thenar flexor pollicis brevis muscles (deep head supplied by ulnar nerve) Palmar view Communicating branch of median nerve with ulnar nerve 1st and 2nd lumbrical muscles Common palmar digital nerves Proper palmar digital nerves Dorsal branches to dorsum of middle and distal phalanges Posterior (dorsal) view 44
  • 49. NEUROANATOMY Ulnar Nerve Anterior view Note: Only muscles innervated by ulnar nerve shown Ulnar nerve (C7, 8, T1) (no branches above elbow) Inconstant contribution Medial epicondyle Articular branch (behind condyle) Cutaneous innervation Flexor digitorum profundus muscle (medial part only; lateral part supplied by anterior interosseous branch of median nerve) Palmar view Flexor carpi ulnaris muscle (drawn aside) Dorsal branch of ulnar nerve Posterior (dorsal) view Palmar branch Flexor pollicis brevis muscle Superficial branch (deep head only; superficial head and other thenar muscles supplied by median nerve) Deep branch Palmaris brevis Adductor pollicis muscle Abductor digiti minimi Hypothenar muscles Flexor digiti minimi brevis Opponens digiti minimi Common palmar digital nerve Communicating branch of median nerve with ulnar nerve Palmar and dorsal interosseous muscles 3rd and 4th lumbrical muscles (turned down) Proper palmar digital nerves (dorsal digital nerves are from dorsal branch) Dorsal branches to dorsum of middle and distal phalanges 45
  • 50. NEUROANATOMY Radial Nerve in Arm and Nerves of Posterior Shoulder Dorsal scapular nerve (C5) Posterior view Supraspinatus muscle Suprascapular nerve (C5, 6) Levator scapulae muscle (supplied Deltoid muscle also by branches from C3 and C4) Teres minor muscle Axillary nerve (C5, 6) Superior lateral Rhomboid cutaneous nerve of arm minor muscle Radial nerve (C5, 6, 7, 8, T1) Inconstant contribution Rhomboid major muscle Inferior lateral cutaneous nerve of arm Posterior cutaneous nerve of forearm Infraspinatus muscle Teres major muscle Lateral intermuscular septum Lower subscapular nerve (C5, 6) Posterior cutaneous nerve of arm (branch of radial nerve in axilla) Brachialis muscle (lateral part; remainder of muscle supplied by musculo- Long head cutaneous nerve) Lateral head Triceps brachii muscle Medial head Brachioradialis muscle Triceps brachii tendon Medial epicondyle Extensor carpi radialis longus muscle Olecranon Extensor carpi Anconeus muscle radialis brevis muscle Extensor digitorum muscle Extensor carpi ulnaris muscle 46
  • 51. NEUROANATOMY Radial Nerve in Forearm Inconstant contribution Radial nerve (C5, 6, 7, 8, T1) Superficial (terminal) branch Deep (terminal) branch Posterior view Lateral epicondyle Anconeus muscle Brachioradialis muscle Extensor carpi radialis longus muscle Supinator muscle Extensor carpi radialis brevis muscle Extensor- supinator Extensor carpi ulnaris muscle group of muscles Extensor digitorum muscle and extensor digiti minimi muscle Extensor indicis muscle Extensor pollicis longus muscle Abductor pollicis longus muscle Extensor pollicis brevis muscle Posterior interosseous nerve (continuation of deep branch of radial nerve distal to supinator muscle) Superficial branch of radial nerve Superior lateral From axillary nerve cutaneous nerve of arm Inferior lateral cutaneous nerve of arm Posterior cutaneous nerve of arm From radial nerve Posterior cutaneous nerve of forearm Superficial branch of radial nerve and dorsal digital branches Dorsal digital nerves Cutaneous innervation from radial and axillary nerves 47
  • 52. NEUROANATOMY Sciatic Nerve and Posterior Cutaneous Nerve of Thigh Posterior cutaneous nerve of thigh (S1, 2, 3) Greater sciatic foramen Inferior cluneal nerves Sciatic nerve (L4, 5, S1, 2, 3) Perineal branches Common fibular (peroneal) Tibial division division of sciatic nerve of sciatic nerve Long head (cut) of Short head of Cutaneous innervation biceps femoris muscle biceps femoris muscle Adductor magnus muscle (also partially supplied Long head (cut) by obturator nerve) of biceps femoris muscle Semitendinosus muscle Common fibular (peroneal) nerve Semimembranosus muscle Tibial nerve Articular Posterior branch cutaneous nerve Articular branch of thigh Lateral sural Plantaris muscle cutaneous nerve Medial sural Sural cutaneous nerve communicating branch Common fibular Gastrocnemius muscle (peroneal) nerve via lateral sural cutaneous nerve Sural nerve Medial sural cutaneous nerve Soleus muscle From sciatic Superficial fibular nerve (peroneal) nerve Tibial nerve Sural nerve Lateral calcaneal Tibial nerve Medial branches via medial calcaneal branches calcaneal branches Lateral dorsal Medial and lateral cutaneous nerve plantar nerves 48
  • 53. NEUROANATOMY Tibial Nerve Common fibular (peroneal) nerve Tibial nerve Articular branch (L4, 5, S1, 2, 3) Lateral sural cutaneous nerve (cut) Medial sural cutaneous nerve (cut) Medial calcaneal branches (S1, 2) Articular branches Medial From plantar nerve tibial nerve (L4, 5) Plantaris muscle Lateral plantar nerve (S1, 2) Gastrocnemius muscle (cut) Saphenous nerve (L3, 4) Sural nerve Nerve to popliteus muscle (S1, 2) via lateral calcaneal and lateral dorsal cutaneous Popliteus muscle branches Cutaneous innervation of sole Interosseous nerve of leg Flexor Lateral calcaneal Soleus muscle (cut and retinaculum branch of sural nerve partly retracted) (cut) Lateral plantar Tibial nerve nerve Flexor digitorum Nerve to abductor Medial longus muscle digiti minimi muscle calcaneal branch Quadratus plantae muscle and nerve Medial plantar Tibialis posterior muscle nerve Abductor digiti minimi muscle Flexor digitorum brevis muscle Deep branch to Flexor hallucis and nerve interosseous longus muscle muscles, Abductor hallucis 2nd, 3rd and 4th muscle and nerve lumbrical muscles Flexor hallucis Sural nerve (cut) and brevis muscle Adductor hallucis and nerve muscle 1st lumbrical Lateral calcaneal branch Superficial muscle and branch to nerve 4th interosseous Common muscle Medial plantar and calcaneal branch digital Flexor digiti minimi nerves brevis muscle Proper Common and Flexor retinaculum (cut) plantar Proper plantar digital digital nerves nerves Lateral dorsal cutaneous nerve Note: Articular branches not shown 49
  • 54. NEUROANATOMY Common Fibular (Peroneal) Nerve Lateral sural cutaneous nerve (phantom) Common fibular (peroneal) nerve (phantom) Articular branches Biceps femoris tendon Recurrent articular nerve Common fibular (peroneal) nerve (L4, 5, S1, 2) Extensor digitorum longus muscle (cut) Head of fibula Deep fibular (peroneal) nerve Fibularis (peroneus) longus muscle (cut) Tibialis anterior muscle Cutaneous innervation Superficial fibular (peroneal) nerve Extensor digitorum Branches of lateral longus muscle sural cutaneous nerve Fibularis (peroneus) longus muscle Extensor hallucis longus muscle Fibularis (peroneus) brevis muscle Lateral sural cutaneous nerve Medial dorsal cutaneous nerve Superficial fibular (peroneal) nerve Lateral branch of Intermediate dorsal deep fibular cutaneous nerve (peroneal) nerve to Extensor hallucis brevis and Extensor digitorum brevis Inferior extensor Deep muscles retinaculum (partially cut) fibular (peroneal) nerve Medial branch of deep fibular Lateral dorsal cutaneous nerve (peroneal) nerve (branch of sural nerve) Sural nerve via lateral dorsal cutaneous branch Dorsal digital nerves 50
  • 55. Click any title below to link to that plate. Part 2 Neurophysiology Organization of the Brain: Cerebrum. . . . . . . 52 The Cerebral Cortex . . . . . . . . . . . . . . . . . . . . 70 Organization of the Brain: Cell Types. . . . . . . 53 Descending Motor Pathways . . . . . . . . . . . . . 71 Blood-Brain Barrier . . . . . . . . . . . . . . . . . . . . . 54 Cerebellum: Afferent Pathways. . . . . . . . . . . . 72 Synaptic Transmission: Cerebellum: Efferent Pathways . . . . . . . . . . . . 73 Morphology of Synapses . . . . . . . . . . . . . . . 55 Cutaneous Sensory Receptors . . . . . . . . . . . . . 74 Synaptic Transmission: Cutaneous Receptors: Neuromuscular Junction . . . . . . . . . . . . . . . 56 Pacinian Corpuscle. . . . . . . . . . . . . . . . . . . . 75 Synaptic Transmission: Proprioception and Reflex Pathways: I . . . . . . 76 Visceral Efferent Endings . . . . . . . . . . . . . . . 57 Proprioception and Reflex Pathways: II . . . . . 77 Synaptic Transmission: Inhibitory Mechanisms . . . . . . . . . . . . . . . . 58 Proprioception and Reflex Pathways: III . . . . 78 Synaptic Transmission: Proprioception and Reflex Pathways: IV. . . . . 79 Chemical Synaptic Transmission . . . . . . . . . 59 Sensory Pathways: I . . . . . . . . . . . . . . . . . . . . . 80 Synaptic Transmission: Sensory Pathways: II . . . . . . . . . . . . . . . . . . . . 81 Temporal and Spatial Summation . . . . . . . . 60 Sensory Pathways: III. . . . . . . . . . . . . . . . . . . . 82 Cerebrospinal Fluid (CSF): Brain Ventricles and CSF Composition . . . . 61 Visual System: Receptors. . . . . . . . . . . . . . . . . 83 Cerebrospinal Fluid (CSF): Visual System: Visual Pathway . . . . . . . . . . . . 84 Circulation of CSF . . . . . . . . . . . . . . . . . . . . 62 Auditory System: Cochlea . . . . . . . . . . . . . . . . 85 Spinal Cord: Ventral Rami. . . . . . . . . . . . . . . . 63 Auditory System: Pathways . . . . . . . . . . . . . . . 86 Spinal Cord: Membranes and Nerve Roots . . 64 Vestibular System: Receptors . . . . . . . . . . . . . 87 Peripheral Nervous System . . . . . . . . . . . . . . . 65 Vestibular System: Vestibulospinal Tracts. . . . 88 Autonomic Nervous System: Schema . . . . . . . 66 Gustatory (Taste) System: Receptors . . . . . . . 89 Autonomic Nervous System: Cholinergic and Adrenergic Synapses . . . . . 67 Gustatory (Taste) System: Pathways . . . . . . . . 90 Hypothalamus . . . . . . . . . . . . . . . . . . . . . . . . . 68 Olfactory System: Receptors . . . . . . . . . . . . . . 91 Limbic System . . . . . . . . . . . . . . . . . . . . . . . . . 69 Olfactory System: Pathway . . . . . . . . . . . . . . . 92
  • 56. NEUROPHYSIOLOGY Organization of the Brain: Cerebrum Postcentral gyrus Central sulcus (Rolando) Precentral gyrus Postcentral sulcus Precentral sulcus Superior parietal lobule Inferior parietal lobule Supramarginal gyrus Angular gyrus Parietooccipital sulcus Occipital pole Frontal pole Calcarine sulcus Lateral sulcus (Sylvius) Superior temporal gyrus Inferior temporal gyrus Temporal pole Middle temporal gyrus Frontal lobe Parietal lobe Temporal lobe Occipital lobe Insula (island of Reil) © FIGURE 2.1 ORGANIZATION BRAIN: CEREBRUM• OF THE The cerebral cortex represents the highest center for sensory and coordinates smooth motor activities and processes muscle position. motor processing. In general, the frontal lobe processes motor, The brainstem (medulla, pons, midbrain) conveys motor and sensory visual, speech, and personality modalities. The parietal lobe information and mediates important autonomic functions. The spinal processes sensory information; the temporal lobe, auditory and cord receives sensory input from the body and conveys somatic and memory modalities; and the occipital lobe, vision. The cerebellum autonomic motor information to peripheral targets (muscles, viscera). 52
  • 57. NEUROPHYSIOLOGY Organization of the Brain: Cell Types Bipolar cell of cranial n. Multipolar (pyramidal) cell of cerebral Unipolar cell of motor cortex sensory ganglia of cranial nn. Satellite cells Schwann cell Astrocyte Interneurons Striated Blood vessel (somatic) Free nerve endings muscle (unmyelinated fibers) Encapsulated ending Motor Specialized ending endplate Multipolar somatic Muscle spindle motor cell of nuclei Unipolar sensory cell of cranial nn. of dorsal spinal Multipolar cell root ganglion Interneuron of lower brain Satellite cells motor centers Oligodendrocyte Myelinated afferent Astrocyte fiber of spinal nerve Corticospinal (pyramidal) fiber Multipolar visceral motor (autonomic) Axodendritic ending cell of spinal cord Axosomatic ending Myelin sheath Axoaxonic ending Autonomic preganglionic Red: Motor neuron (sympathetic or para- Multipolar somatic Blue: Sensory neuron sympathetic) nerve fiber motor cell of Purple: Interneuron anterior horn Myelin sheath Gray: Glial and of spinal cord Autonomic postganglionic neurilemmal cells Collateral neuron of sympathetic or and myelin parasympathetic ganglion Note: Cerebellar cells Renshaw interneuron Satellite cells not shown here (feedback) Unmyelinated nerve fiber Myelinated somatic motor Schwann cells fiber of spinal nerve Myelin sheath Schwann cells Motor endplate with Endings on Unmyelinated fibers Schwann cell cap cardiac muscle or nodal cells Striated Free nerve endings (voluntary) Beaded muscle varicosities Encapsulated ending and endings on smooth muscle Muscle spindle and gland cells © FIGURE 2.2 ORGANIZATION BRAIN: CELL TYPES• OF THE Neurons form the functional cellular units responsible for (e.g., astrocytes, oligodendrocytes), satellite cells, and other spe- communication, and throughout the nervous system, they are cialized cells that optimize neuronal function, provide mainte- characterized by their distinctive size and shapes (e.g., bipolar, nance functions, or protect the nervous system. unipolar, multipolar). Supporting cells include the neuroglia 53
  • 58. NEUROPHYSIOLOGY Blood-Brain Barrier Cell membrane Basement membrane Tight junction proteins Cytoplasm Red blood cell Astrocyte Capillary foot processes lumen Tight Capillary junction endothelial cell Astrocyte © FIGURE 2.3 BLOOD-BRAIN BARRIER• The blood-brain barrier (BBB) is the cellular interface between the other substances (including many drugs) from the blood to the blood and the central nervous system (CNS; brain and spinal cord). interstitial space of the CNS is restricted by the BBB. CNS endothe- It serves to maintain the interstitial fluid environment to ensure lial cells also exhibit a low level of pinocytotic activity across the optimal functionality of the neurons. This barrier consists of the cell, so specific carrier systems for the transport of essential sub- capillary endothelial cells with an elaborate network of tight junc- strates of energy and amino acid metabolism are characteristic of tions and astrocytic foot processes that abut the endothelium and these cells. The astrocytes help transfer important metabolites from its basement membrane. The movement of large molecules and the blood to the neurons and also remove excess K and neuro- transmitters from the interstitial fluid. 54
  • 59. NEUROPHYSIOLOGY Synaptic Transmission: Morphology of Synapses Dendrite Axon Node Myelin sheath Dendrites Numerous boutons (synaptic knobs) of presynaptic neurons terminating on a motor neuron and its dendrites Enlarged section of bouton Axon (axoplasm) Axolemma Mitochondria Glial process Synaptic vesicles Synaptic cleft Presynaptic membrane (densely staining) Postsynaptic membrane (densely staining) Postsynaptic cell © FIGURE 2.4 MORPHOLOGY OF SYNAPSES• Neurons communicate with each other and with effector targets at lower figure shows an enlargement of one such synaptic bouton. specialized regions called synapses. The top figure shows a typical Chemical neurotransmitters are contained in synaptic vesicles, motor neuron that receives numerous synaptic contacts on its cell which can fuse with the presynaptic membrane, release the trans- body and associated dendrites. Incoming axons lose their myelin mitters into the synaptic cleft, and then bind to receptors situated sheaths, exhibit extensive branching, and terminate as synaptic in the postsynaptic membrane. This synaptic transmission results in boutons (synaptic terminals or knobs) on the motor neuron. The excitatory, inhibitory, or modulatory effects on the target cell. 55
  • 60. NEUROPHYSIOLOGY Synaptic Transmission: Neuromuscular Junction Structure of Neuromuscular Junction Active zone Myelin sheath Neurilemma Schwann cell process Axoplasm Acetylcholine Schwann cell receptor sites Mitochondria Basement membrane Nucleus of Schwann cell Presynaptic membrane Active zone Synaptic vesicles Synaptic trough Basement membrane Sarcolemma Nucleus of muscle cell Myofibrils Synaptic cleft Postsynaptic membrane Junctional fold Sarcoplasm Acetylcholine receptor sites © FIGURE 2.5 STRUCTURE NEUROMUSCULAR JUNCTION• OF THE Motor axons that synapse on skeletal muscle form expanded termi- ately stimulated, release their neurotransmitter into the synaptic nals called neuromuscular junctions (motor endplates). The motor cleft. The transmitter then binds to receptors that mediate depolar- axon loses its myelin sheath and expands into a Schwann ization of the muscle sarcolemma and initiate a muscle action cell–invested synaptic terminal that resides within a trough in the potential. A single muscle fiber has only one neuromuscular junc- muscle fiber. Acetylcholine-containing synaptic vesicles accumu- tion, but a motor axon can innervate multiple muscle fibers. late adjacent to the presynaptic membrane and, when appropri- 56
  • 61. NEUROPHYSIOLOGY Synaptic Transmission: Visceral Efferent Endings Visceral Efferent Endings                      B. Gland (submandibular) C. Neurosecretory A. Smooth muscle (posterior pituitary) Sympathetic terminal ending Pituicyte processes Mucous cells Smooth muscle cells (cut) Varicosity Axon Axon Schwann cell Schwann cap enclosing Schwann cell cap enclosing cell cap nerve axons nerve axons Fibroblast Schwann cell cap Capillary Neurosecretory Schwann cell Serous cells Smooth muscle cells vesicles cap enclosing Endothelium nerve axons Parasympathetic Varicosities Collagen space terminal ending Mast cell Terminal endings Varicosity Basement membrane © FIGURE 2.6 VISCERAL EFFERENT ENDINGS• Neuronal efferent endings on smooth muscle (A) and glands (B rosecretion) from expanded nerve terminal endings. This arrange- and C) exhibit unique endings unlike the presynaptic and postsy- ment allows for the stimulation of numerous target cells over a naptic terminals observed in neuronal and neuromuscular junc- wide area. Not all smooth muscle cells are innervated. They are tion synapses. Rather, neurotransmitter substances are released connected to adjacent cells by gap junctions and can therefore into interstitial spaces (A and B) or into the bloodstream (C, neu- contract together with the innervated cells. 57
  • 62. NEUROPHYSIOLOGY Synaptic Transmission: Inhibitory Mechanisms E I E (Excitatory (Inhibitory (Excitatory fiber) fiber) fiber) Motor neuron Motor neuron I Axon Axon (Inhibitory fiber) mV 20 mV A. Only E fires 90-mV spike 90 mV A′. Only E fires in E terminal EPSP in 70 motor 60 60 EPSP in neuron motor neuron 70 70 B. Only I fires B′. Only I fires Long-lasting partial Motor 60 depolarization neuron 70 70 in E terminal hyper- polarized No response in 80 motor neuron 70 C. I fires before E C′. I fires before E Partial 60 depolarization Depolariza- 20 of E terminal tion of motor 70 reduces spike neuron less 80 mV to 80 mV, thus than if only 80 releasing less E fires transmitter 70 substance 60 Smaller EPSP in motor neuron 70 © FIGURE 2.7 SYNAPTIC INHIBITORY MECHANISMS• Inhibitory synapses modulate neuronal activity. Illustrated here is presynaptic inhibition (left panel) and postsynaptic inhibition (right panel) at a motor neuron. 58
  • 63. NEUROPHYSIOLOGY Synaptic Transmission: Chemical Synaptic Transmission               Inhibitory Excitatory Synaptic vesicles in synaptic bouton Presynaptic membrane Transmitter substances Na Synaptic cleft Cl Postsynaptic K membrane When impulse reaches excitatory synaptic At inhibitory synapse, transmitter substance re- bouton, it causes release of a transmitter leased by an impulse increases permeability of substance into synaptic cleft. This increases the postsynaptic membrane to Cl . K moves permeability of postsynaptic membrane to out of post-synaptic cell but no net flow of Cl Na and K . More Na moves into postsy- occurs at resting membrane potential naptic cell than K moves out, due to great- er electrochemical gradient Synaptic bouton Resultant net ionic current flow is in a direc- Resultant ionic current flow is in direction that tends to tion that tends to depolarize postsynaptic cell. hyperpolarize postsynaptic cell. This makes depolariza- If depolarization reaches firing threshold, an tion by excitatory synapses more difficult—more depolari- impulse is generated in postsynaptic cell zation is required to reach threshold msec Current 0 4 8 12 16 70 Potential (mV) Potential (mV) 65 Potential Potential 75 Current 70 0 4 8 12 16 msec Current flow and potential change Current flow and potential change © FIGURE 2.8 CHEMICAL SYNAPTIC TRANSMISSION• Chemical synaptic transmission between neurons may be excita- threshold for an action potential. During inhibition (right column), tory or inhibitory. During excitation (left column), a net increase in the opening of K and Cl channels drives the membrane potential the inward flow of Na compared with the outward flow of K away from threshold (hyperpolarization) and decreases the proba- results in a depolarizing potential change (excitatory postsynaptic bility that the neuron will reach threshold (inhibitory postsynaptic potential [EPSP]) that drives the postsynaptic cell closer to its potential [IPSP]) for an action potential. 59
  • 64. NEUROPHYSIOLOGY Synaptic Transmission: Temporal and Spatial Summation Temporal and Spatial Summation of Excitation and Inhibition Excitatory fibers mV Excitatory fibers mV –70 –70 Axon Axon Inhibitory fibers Inhibitory fibers A. Resting state: motor nerve cell shown with synaptic boutons of B. Partial depolarization: impulse from one excitatory fiber has excitatory and inhibitory nerve fibers ending close to it caused partial (below firing threshold) depolarization of motor neuron mV Excitatory fibers mV Excitatory fibers –70 –70 Axon Axon Inhibitory fibers Inhibitory fibers C. Temporal excitatory summation: a series of impulses in one D. Spatial excitatory summation: impulses in two excitatory fibers excitatory fiber together produce a suprathreshold depolarization cause two synaptic depolarizations that together reach firing that triggers an action potential threshold triggering an action potential mV mV Excitatory fibers Excitatory fibers –70 –70 Axon Axon Inhibitory fibers Inhibitory fibers E. (continued): motor neuron now receives additional excitatory E. Spatial excitatory summation with inhibition: impulses from impulses and reaches firing threshold despite a simultaneous two excitatory fibers reach motor neuron but impulses from inhibitory impulse; additional inhibitory impulses might still inhibitory fiber prevent depolarization from reaching threshold prevent firing © CHART 2.1 SUMMARY OF SOME NEUROTRANSMITTERS AND WHERE WITHIN THE CENTRAL AND PERIPHERAL NERVOUS SYSTEM THEY ARE FOUND Transmitter Location Transmitter Location Acetylcholine Neuromuscular junction, autonomic end- Gas ings and ganglia, CNS Nitric oxide CNS, GI tract Biogenic amines Peptides Norepinephrine Sympathetic endings, CNS -Endorphins CNS, GI tract Dopamine CNS Enkephalins CNS Serotonin CNS, GI tract Antidiuretic CNS (hypothalamus/posterior Amino acids hormone pituitary) -Aminobutyric CNS Pituitary-releasing CNS (hypothalamus/anterior acid (GABA) hormones pituitary) Glutamate CNS Somatostatin CNS, GI tract Neuropeptide Y CNS Purines Vasoactive Adenosine CNS intestinal peptide CNS, GI tract Adenosine CNS triphosphate (ATP) CNS, Central nervous system; GI, gastrointestinal. FIGURE 2.9 TEMPORAL SPATIAL SUMMATION • AND Neurons receive multiple excitatory and inhibitory inputs. Tempo- tial (panel D). Both temporal and spatial summation can be modu- ral summation occurs when a series of subthreshold impulses in lated by simultaneous inhibitory input (panel E). Inhibitory and one excitatory fiber produces an action potential in the postsynap- excitatory neurons use a wide variety of neurotransmitters, some of tic cell (panel C). Spatial summation occurs when subthreshold which are summarized here. impulses from two or more different fibers trigger an action poten- 60
  • 65. NEUROPHYSIOLOGY Cerebrospinal Fluid (CSF): Brain Ventricles and CSF Composition Left lateral phantom view Frontal (anterior) horn Right lateral ventricle Left Central part lateral Temporal (inferior) horn ventricle Occipital (posterior) horn Cerebral aqueduct (Sylvius) 4th ventricle Left lateral aperture (foramen of Luschka) Left lateral recess Left interventricular Median aperture foramen (Monro) (foramen of Magendie) 3rd ventricle Central canal of spinal cord © CHART 2.2 CSF COMPOSITION CSF Blood Plasma Na (mEq/L) 140–145 135–147 K (mEq/L) 3 3.5–5.0 Cl− (mEq/L) 115–120 95–105 HCO3− (mEq/L) 20 22–28 Glucose (mg/dL) 50–75 70–110 Protein (g/dL) 0.05–0.07 6.0–7.8 pH 7.3 7.35–7.45 FIGURE 2.10 BRAIN VENTRICLES CSF COMPOSITION• AND CSF circulates through the four brain ventricles (two lateral ventri- secretes the CSF. Importantly, the CSF has a lower [HCO3 ] than cles and a third and fourth ventricle) and in the subarachnoid plasma and therefore a lower pH. This allows small changes in space surrounding the brain and spinal cord. The electrolyte com- blood PCO2 to cause changes in CSF pH, which in turn regulates position of the CSF is regulated by the choroid plexus, which the rate of respiration (see Chapter 5). 61
  • 66. NEUROPHYSIOLOGY Cerebrospinal Fluid (CSF): Circulation of CSF Choroid plexus of lateral ventricle (phantom) Superior sagittal sinus Subarachnoid space Cistern of corpus callosum Arachnoid granulations Dura mater Arachnoid Interventricular foramen (Monro) Choroid plexus of 3rd ventricle Cerebral aqueduct (Sylvius) Lateral aperture (foramen of Luschka) Choroid plexus of 4th ventricle Median aperture (foramen of Magendie) Dura mater Arachnoid Subarachnoid space Central canal of spinal cord © FIGURE 2.11 CIRCULATION CEREBROSPINAL FLUID• OF CSF circulates through the four brain ventricles (two lateral ventri- reabsorbed into the venous system through the arachnoid granula- cles and a third and fourth ventricle) and in the subarachnoid tions and through the walls of the capillaries of the central nervous space surrounding the brain and spinal cord. Most of the CSF is system and pia mater. 62
  • 67. NEUROPHYSIOLOGY Spinal Cord: Ventral Rami Base of skull C1 vertebra (atlas) C1 spinal nerve Cervical plexus C8 spinal nerve Brachial plexus T1 spinal nerve Spinal dura mater 1st rib Filaments of spinal nerve roots (T7 and T8) Intercostal nerves T12 spinal nerve L1 12th rib vertebra Conus medullaris Lumbar plexus L1 spinal nerve L5 vertebra Cauda equina S1 spinal nerve Sacral plexus Sacrum (cut away) Termination of dural sac Sciatic nerve Coccygeal nerve Coccyx © FIGURE 2.12 SPINAL CORD VENTRAL RAMI IN SITU• AND The spinal cord gives rise to 31 pairs of spinal nerves that distribute fibers of these spinal nerves innervate skeletal muscle, and sensory segmentally to the body. These nerves are organized into plexuses fibers convey information back to the central nervous system from that distribute to the neck (cervical plexus), upper limb (brachial the skin, skeletal muscles, and joints. plexus), and pelvis and lower limb (lumbosacral plexus). Motor 63
  • 68. NEUROPHYSIOLOGY Spinal Cord: Membranes and Nerve Roots Posterior view Ventral root of spinal nerve Dorsal root of spinal nerve Spinal sensory (dorsal root) ganglion Ventral ramus of spinal nerve Dorsal ramus of spinal nerve Dura mater Arachnoid mater Subarachnoid space Pia mater overlying spinal cord Filaments of dorsal root Membranes removed: anterior view (greatly magnified) Gray matter Filaments of dorsal root White matter Dorsal root of spinal nerve Filaments of ventral root Spinal sensory (dorsal root) ganglion Dorsal ramus of spinal nerve Ventral ramus of spinal nerve Ventral root of spinal nerve Spinal nerve Gray and white rami communicantes © FIGURE 2.13 SPINAL MEMBRANES NERVE ROOTS• AND The spinal cord gives rise to 31 pairs of spinal nerves that distribute The spinal cord is ensheathed in three meningeal coverings: the segmentally to the body. Motor fibers of these spinal nerves inner- outer, tough dura mater; the arachnoid mater; and the pia mater, vate skeletal muscle, and sensory fibers convey information back which intimately ensheaths the cord itself. CSF bathes the cord and to the central nervous system from the skin, skeletal muscles, and is found in the subarachnoid space. joints. 64
  • 69. NEUROPHYSIOLOGY Peripheral Nervous System Posterior horn Dorsal root ganglion Sensory neuron cell body Dorsal root Anterior horn Motor neuron cell body Ventral root Peripheral nerve Axon Myelin sheath Motor neuron Sensory neuron Neuromuscular junction Skin Muscle with © FIGURE 2.14 PERIPHERAL NERVOUS SYSTEM• The peripheral nervous system (PNS) consists of all of the neural shown here (see Figure 2.15 for the autonomic nervous system). elements outside of the CNS (brain and spinal cord) and provides The somatic component of the peripheral nerves contains both the connections between the CNS and all other body organ sys- motor and sensory axons. Cell bodies of the motor neurons are tems. The PNS consists of somatic and autonomic components. The found in the anterior horn gray matter, whereas the cell bodies of somatic component innervates skeletal muscle and skin and is sensory neurons are located in the dorsal root ganglia. 65
  • 70. NEUROPHYSIOLOGY Autonomic Nervous System: Schema Intracranial vessels Oculomotor nerve (III) Ciliary ganglion Facial nerve (VII) Eye Glossopharyngeal nerve (IX) Pterygopalatine ganglion Medulla oblongata Lacrimal glands Vagus nerve (X) Otic ganglion Parotid glands C1 Gray ra ntes Submandibular ganglion Sublingual and mi C2 ica submandibular glands ommun C3 Peripheral cranial C4 and facial vessels C5 c Larynx C6 Trachea C7 Bronchi C8 Lungs Sweat T1 gland Pulmonary plexus T2 T3 tes Heart Cardiac plexus Gray and white rami communican T4 Greater  Splanchnic Peripheral T5 Lesser  nerves Celiac ganglion blood vessel Least  T6 Stomach Aorticorenal ganglion T7 Liver T8 Gallbladder Bile ducts T9 Lumbar Pancreas splanchnic Superior mesenteric T10 nerves ganglion Suprarenal glands T11 Kidneys Arrector (smooth) T12 Inferior mesenteric muscle of hair follicle ganglion Note: Above three L1 structures are shown at Intestines L2 Superior hypogastric only one level but occur at all levels plexus L3 antes Descending colon L4 Sigmoid colon L5 munic Rectum S1 Note: Blue-shaded Inferior co m areas indicate zones of hypogastric Urinary bladder parasympathetic S2 plexus a mi outflow from CNS S3 ay r Pelvic S4 Prostate splanchnic S5 Gr nerves External genitalia Coccygeal © Presynaptic Presynaptic Sympathetic Parasympathetic Antidromic fibers fibers conduction Postsynaptic Postsynaptic FIGURE 2.15 AUTONOMIC NERVOUS SYSTEM: SCHEMA• The autonomic nervous system is composed of two divisions: the a peripheral autonomic ganglion. Postganglionic axons of the auto- parasympathetic division derived from four of the cranial nerves nomic nervous system innervate smooth muscle, cardiac muscle, and (CN III, VII, IX, and X) and the S2-S4 sacral spinal cord levels, and the glands. Basically, the sympathetic division mobilizes our body (“fight sympathetic division associated with the thoracic and upper lumbar or flight”) while the parasympathetic division regulates digestive and spinal cord levels (T1-L2). The autonomic nervous system is a two- homeostatic functions. Normally, both divisions work in concert to neuron chain, with the preganglionic neuron arising from the central regulate visceral activity (respiration, cardiovascular function, diges- nervous system and synapsing on a postganglionic neuron located in tion, and associated glandular activity). 66
  • 71. NEUROPHYSIOLOGY Autonomic Nervous System: Cholinergic and Adrenergic Synapses Parotid Glossopharyngeal gland nerve (IX) Larynx Trachea Medulla Internal carotid nerve Bronchi oblongata Lungs Vagus nerve (X) Heart Cervical sympathetic ganglia Striated muscle Sweat glands White ramus Hair follicles Gray ramus communicans Thoracic communicans part of Celiac spinal cord ganglion Peripheral arteries Superior mesenteric Visceral ganglion Upper arteries lumbar part of Gastrointestinal spinal cord tract Suprarenal (L1-2 [3]) gland Inferior mesenteric ganglion Pelvic splanchnic nerves Sacral part of Urinary bladder spinal cord Urethra C Cholinergic synapses Prostate A Adrenergic synapses Presynaptic Presynaptic Sympathetic Parasympathetic fibers fibers Postsynaptic Postsynaptic Somatic fibers Antidromic conduction © FIGURE 2.16 CHOLINERGIC ADRENERGIC SYNAPSES: SCHEMA• AND The autonomic nervous system (ANS) is a two-neuron chain, with aline (norepinephrine) at its postganglionic synapses, causing the preganglionic neuron arising from the central nervous system adrenergic (A) effects (except on sweat glands, where acetylcholine and synapsing on a postganglionic neuron located in a peripheral is released). Although acetylcholine and noradrenaline are the autonomic ganglion. Acetylcholine is the neurotransmitter in both chief transmitter substances, other neuroactive peptides often are the sympathetic and parasympathetic ganglia. The parasympathetic colocalized with them and include such substances as gamma- division of the ANS releases acetylcholine at its postganglionic aminobutyric acid (GABA), substance P, enkephalins, histamine, synapses and is characterized as having cholinergic (C) effects, glutamic acid, neuropeptide Y, and others. whereas the sympathetic division releases predominantly noradren- 67
  • 72. NEUROPHYSIOLOGY Hypothalamus Corpus callosum Septum Fornix pellucidum Lateral ventricle From Thalamus hippocampal formation Interthalamic Lateral adhesion hypothalamic area Paraventricular nucleus Medial Anterior hypothalamic area Anterior forebrain commissure Dorsal hypothalamic area bundle Dorsomedial nucleus Mamillothalamic tract Posterior area Lateral Periventricular preoptic Medial nucleus nucleus preoptic Nucleus intercalatus nucleus Olfactory tract Cerebral Fornix Red nucleus peduncle Ventromedial Mamillary nucleus complex Optic (II) Dorsal nerve Tuberohypophyseal tract longitudinal Optic chiasm fasciculus Oculomotor (III) nerve Descending Supraoptic nucleus hypothalamic Supraopticohypophyseal connections tract Pons Posterior lobe of pituitary Reticular Anterior formation lobe of pituitary © CHART 2.3 MAJOR FUNCTIONS OF THE HYPOTHALAMUS Hypothalamic Area Major Functions* Preoptic and anterior Heat loss center: cutaneous vasodilation and sweating Posterior Heat conservation center: cutaneous vasoconstriction and shivering Lateral Feeding center: eating behavior Ventromedial Satiety center: inhibits eating behavior Supraoptic (subfornical organ and organum vasculosum) ADH and oxytocin secretion (sensation of thirst) Paraventricular ADH and oxytocin secretion Periventricular Releasing hormones for the anterior pituitary *Stimulation of the center causes the responses listed. FIGURE 2.17 SCHEMATIC RECONSTRUCTION HYPOTHALAMUS• OF THE The hypothalamus, part of the diencephalon, controls a number of information), the thalamus (pain), the limbic system (emotion, fear, important homeostatic systems within the body, including tempera- anger, smell), the medulla oblongata (blood pressure and heart ture regulation, food intake, water intake, many of the endocrine rate), and the optic system, and it integrates these inputs for regula- systems (see Chapter 8), motivation, and emotional behavior. It tion of the functions listed. receives inputs from the reticular formation (sleep/wake cycle 68
  • 73. NEUROPHYSIOLOGY Limbic System Genu of corpus callosum Head of caudate nucleus Columns of fornix Body of fornix Thalamus Uncus Crura of fornix Fimbria of hippocampus Hippocampus Commissure of fornix Splenium of corpus callosum Lateral ventricle Body of fornix Columns of fornix Commissure of fornix Crura of fornix Mamillary bodies Hippocampus © with fimbria Amygdaloid bodies FIGURE 2.18 HIPPOCAMPUS FORNIX• AND The limbic system includes the hypothalamus and a collection of pocampal formation. The limbic system functions in linking emo- interconnected structures in the telencephalon (cingulate, parahip- tion and motivation (amygdala), learning and memory (hippocam- pocampal, and subcallosal gyri), as well as the amygdala and hip- pal formation), and sexual behavior (hypothalamus). 69
  • 74. NEUROPHYSIOLOGY The Cerebral Cortex Sm I Ms I Sensory Motor Sm II Ms II Premotor; orientation; eye and head Sensory movements analysis Prefrontal; inhibitory control of behavior; higher intelligence Visual III Visual II Visual I Language; Motor control reading; speech of speech Auditory I Auditory II Sm I Ms I Sensory Motor Sm III Ms II ? Premotor Prefrontal; inhibitory control of behavior; higher intelligence Visual III Visual II Visual I Cingulate gyrus © Corpus callosum (emotional behavior) and cingulum Hippocampal commissure Olfactory Anterior commissure FIGURE 2.19 CEREBRAL CORTEX: LOCALIZATION FUNCTION ASSOCIATION PATHWAYS• OF AND The cerebral cortex is organized into functional regions. In addi- including aspects of memory storage and recall, language, higher tion to specific areas devoted to sensory and motor functions, there cognitive functions, conscious perception, sensory integration, and are areas that integrate information from multiple sources. The planning/execution of complex motor activity. General cortical cerebral cortex participates in advanced intellectual functions, areas associated with these functions are illustrated. 70
  • 75. NEUROPHYSIOLOGY Descending Motor Pathways Hip Motor Trunk Shoulder Elbow cortex Fin rist Knee W rs Ankle ge b um Th eck Internal Toes N capsule Browd Eyeli Nares Lateral aspect of Lips cerebral cortex to show Tongue topographic projection Larynx of motor centers on precentral gyrus Midbrain Motor system Basis Fibers originate in motor cortex and pedunculi descend via posterior limb of internal capsule to basis pedunculi of midbrain Pons Longitudinal bundles branch upon entering basis pontis and rejoin to enter pyramids of medulla Basis pontis At lower medulla, bulk of fibers cross median plane to form lateral corticospinal tract; some fibers Medulla continue downward in ipsilateral lateral corticospinal tract; others descending ipsilateral anterior Pyramids corticospinal tract Synapse occurs at spinal level: Lateral corticospinal fibers synapse on ipsilateral anterior horn cells; anterior Medulla corticospinal fibers synapse on contralateral anterior horn cells Decussation of pyramids Above mid- thoracic level Motor endplate Spinal Anterior corticospinal tract Below mid- cord Lateral corticospinal tract thoracic level Motor endplate © FIGURE 2.20 CORTICOSPINAL TRACTS• The corticospinal, or pyramidal, tract is the major motor tract that cord constitute the upper portion of the system (upper motor neu- controls voluntary movement of the skeletal muscles, especially ron). The anterior horn cells and their associated axons constitute skilled movements of distal muscles of the limbs. All structures the lower portion of the system (lower motor neuron). from the cerebral cortex to the anterior horn cells in the spinal 71
  • 76. NEUROPHYSIOLOGY Cerebellum: Afferent Pathways Superior cerebellar peduncle Middle cerebellar peduncle To contralateral cerebellar cortex Cortical input Leg Arm Nucleus Fac reticularis Primary fissure e tegmenti pontis Pontine nuclei (contralateral) Spinal input Inferior olive Upper part To nodule and flocculus of medulla oblongata Inferior cerebellar peduncle Vestibular nuclei Spinal input Functional Subdivisions of Cerebellum Hemisphere Vermis Reticulocerebellar Inter- tract Lateral mediate Vestibular nerve part part Cuneocerebellar Anterior lobe and ganglion tract Leg zone Primary Lower part Arm zone Gracile nucleus fissure Face zone of medulla Main cuneate oblongata nucleus (relay Middle for cutaneous (posterior) Cortical input 2nd spinal information) lobe projection Lateral reticular External cuneate nucleus area (gracile nucleus (relay for proprioceptive lobule) Posterolateral Spinal input information) fissure Archi- Cervical part From skin (touch Lingula cerebellum Flocculo- of spinal cord and pressure) Flocculus (vestibulo- nodular lobe cerebellum) Nodule From muscle (spindles Motor interneuron Paleocerebellum Uvula and Golgi tendon organs) Rostral (spinocerebellum) Pyramid From skin and spinocerebellar Vermis deep tissues tract Neocerebellum Middle vermis (pain and Golgi (pontocerebellum) Hemisphere Spinal border cells tendon organs) Schema of Motor interneuron From skin (touch theoretical and pressure) “unfolding” Lumbar part and from muscle of cerebellar of spinal cord (spindles and surface in Clarke’s column Golgi tendon derivation of organs) above diagram Ventral spino- cerebellar tract Dorsal spinocerebellar tract © FIGURE 2.21 CEREBELLAR AFFERENT PATHWAYS• The cerebellum plays an important role in coordinating movement. It bellum primarily controls movement of the proximal portions of the receives sensory information and then influences descending motor limbs. It receives sensory information on limb position and muscle pathways to produce fine, smooth, and coordinated motion. The tone and then modifies and coordinates these movements through cerebellum is divided into three general areas: archicerebellum (also efferent pathways to the appropriate descending motor pathways. The called vestibulocerebellum) paleocerebellum (also called spinocere- neocerebellum is the largest portion of the cerebellum, and it coordi- bellum) and the neocerebellum (also called the cerebrocerebellum). nates the movement of the distal portions of the limbs. It receives The archicerebellum is primarily involved in controlling posture and input from the cerebral cortex and thus helps in the planning of balance, as well as the movement of the head and eyes. It receives motor activity (e.g., seeing a pencil and then planning and executing afferent signals from the vestibular apparatus and then sends efferent the movement of the arm and hand to pick it up). fibers to the appropriate descending motor pathways. The paleocere- 72
  • 77. NEUROPHYSIOLOGY Cerebellum: Efferent Pathways Excitatory endings Motor and Inhibitory premotor endings of cerebral Purkinje cortex cells Internal capsule Ventral anterior and ventral lateral nuclei of thalamus Cerebral peduncle Mesencephalic reticular formation Decussation of superior cerebellar peduncles Red nucleus Descending fibers from superior cerebellar Fastigial nucleus peduncles Globose nuclei Hook bundle of Russell Emboliform nucleus Dentate nucleus Section A–B viewed Cerebellar from cortex below Section B–C viewed from above Vestibular nuclei Inferior cerebellar A peduncle Planes of Inferior olive section: B Lateral reticular nucleus red arrows indicate Medulla oblongata C direction Pontomedullary reticular formation of view © FIGURE 2.22 CEREBELLAR EFFERENT PATHWAYS• The cerebellum plays an important role in coordinating movement. the proximal portions of the limbs. It modifies and coordinates It influences descending motor pathways to produce fine, smooth, these movements through efferent pathways to the appropriate and coordinated motion. The archicerebellum is primarily involved descending motor pathways. The neocerebellum coordinates the in controlling posture and balance and movement of the head and movement of the distal portions of the limbs. It helps in the plan- eyes. It sends efferent fibers to the appropriate descending motor ning of motor activity (e.g., seeing a pencil and then planning and pathways. The paleocerebellum primarily controls movement of executing the movement of the arm and hand to pick it up). 73
  • 78. NEUROPHYSIOLOGY Cutaneous Sensory Receptors Stratum corneum Meissner’s corpuscle Free nerve endings Stratum Pore of sweat gland Hair shaft lucidum Stratum Melanocyte Epidermis granulosum Arrector muscle of hair Sebaceous gland Stratum spinosum Cuticle Stratum Internal sheath basale Hair follicle External sheath Glassy Dermal membrane papilla (of papillary Connective layer) Dermis tissue layer Reticular layer Hair cuticle Sweat gland Subcutaneous tissue Hair matrix Papilla of hair follicle Pacinian corpuscle Artery Subcutaneous artery and vein Vein Sensory nerves Basement membrane Axon terminal Elastic fibers Cutaneous Mitochondrion Detail of Merkel’s disc Skin ligaments nerve Schwann cell (retinacula cutis) Motor (autonomic) Basal nerve Cross section epithelial Desmosomes cells Merkel cell Cytoplasmic protrusion Lobulated nucleus Mitochondria Granulated Expanded vesicles © Axon axon terminal Schwann cells Schwann cell Detail of free nerve ending FIGURE 2.23 SKIN CUTANEOUS RECEPTORS• AND Cutaneous receptors respond to touch (mechanoreceptors), pain respond best to high-frequency stimulation (i.e., vibration). (nociceptors), and temperature (thermoreceptors). Several different Merkel’s discs have small receptive fields and respond to touch and types of receptors are present in skin. Meissner’s corpuscles have pressure (i.e., indenting the skin). Ruffini’s corpuscles have large small receptive fields and respond best to stimuli that are applied receptive fields, and they also respond to touch and pressure. Free at low frequency (i.e., flutter). The pacinian corpuscles are located nerve endings respond to pain and temperature. in the subcutaneous tissue and have large receptive fields. They 74
  • 79. NEUROPHYSIOLOGY Cutaneous Receptors: Pacinian Corpuscle Pacinian Corpuscle as Pressure Transducer Pressure To amplifier Generator potential Action potential A. Sharp “on and off” changes in pressure at start and end 1st node of pulse applied to lamellated capsule are transmitted to Myelin sheath central axon and provoke generator potentials, which in turn may trigger action potentials; there is no response to a Lamellated capsule slow change in pressure gradient. Pressure at central core and, accordingly, generator potentials are rapidly dissipated Central core by viscoelastic properties of capsule (Action potentials may Unmyelinated axon terminal be blocked by pressure at a node or by drugs) Pressure To amplifier Generator potential B. In absence of capsule, axon responds to slow as well as to rapid changes in pressure. Generator potential Action potential dissipates slowly, and there is no “off” response Na+ Pressure Pressure applied to axon terminal directly or via capsule causes increased permeability of membrane to Na+, thus setting up ionic generator current through 1st node If resultant depolarization at 1st node is great enough to reach threshold, an action potential appears which is propagated along nerve fiber © FIGURE 2.24 PACINIAN CORPUSCLE• Pacinian corpuscles are mechanoreceptors that transduce mechani- producing a “generator potential.” As demonstrated in the figure, cal forces (displacement, pressure, vibration) into action potentials pacinian corpuscles respond to the beginning and end of a that are conveyed centrally by afferent nerve fibers. As the vis- mechanical force while the concentric lamellae dissipate slow coelastic lamellae are displaced, the unmyelinated axon terminal changes in pressure. In the absence of the capsule, the generator membrane’s ionic permeability is increased until it is capable of potential decays slowly and yields only a single action potential. 75
  • 80. NEUROPHYSIOLOGY Proprioception and Reflex Pathways: I Spinal Effector Mechanisms Dorsal horn interneuron From motor neuron From Proprioceptive fibers cutaneous receptor Dorsal horn interneuron From muscle spindle Dorsal root ganglion Flexor reflex interneuron To motor neuron Ventral root Dorsal horn interneuron To motor neuron motor axon Schematic representation of motor neurons In cervical enlargement of spinal cord In lumbar enlargement Flex rs o rs Fl e x o of spinal cord rs s r n so so E xte n Ext e © FIGURE 2.25 PROPRIOCEPTION: SPINAL EFFECTOR MECHANISM• Position sense or proprioception involves input from cutaneous panel) initiate muscle contraction reflexes. The lower panel shows mechanoreceptors, Golgi tendon organs, and muscle spindles the somatotopic distribution of the motor neuron cell bodies in the (middle figure of upper panel). Both monosynaptic reflex pathways ventral horn of the spinal cord that innervate limb muscles (flexor (middle figure of upper panel) and polysynaptic pathways involv- and extensor muscles of upper and lower limbs). ing several spinal cord segments (top and bottom figures of upper 76
  • 81. NEUROPHYSIOLOGY Proprioception and Reflex Pathways: II Alpha motor neurons to extrafusal striated muscle end plates Gamma motor neurons to intrafusal striated muscle end plates Ia (A ) fibers from annulospiral endings (proprioception) II (A ) fibers from flower spray endings (proprioception); from paciniform corpuscles (pressure) and pacinian corpuscles (pressure) III (A ) fibers from free nerve endings and from some specialized endings (pain and some pressure) IV (unmyelinated) fibers from free nerve endings (pain) Ib (A ) fibers from Golgi tendon organs (proprioception) A fibers from Golgi-type endings A fibers from paciniform corpuscles and Ruffini terminals A and C fibers from free nerve endings Alpha motor neuron to extrafusal muscle fiber end plates Gamma motor neuron to intrafusal muscle fiber and plates II (A ) fiber from flower spray endings Extrafusal muscle fiber Ia (A ) fiber from annulospiral endings Intrafusal muscle fibers Sheath Lymph space Nuclear bag fiber Nuclear chain fiber © Detail of Efferent fibers muscle spindle Afferent fibers FIGURE 2.26 MUSCLE JOINT RECEPTORS• AND Muscle spindles and Golgi tendon organs send afferent signals to forces, whereas the nuclear chain fibers respond to static forces. the brain to convey the position of limbs and help coordinate mus- Intrafusal fibers maintain appropriate tension on the nuclear bag cle movement. Muscle spindles convey information on muscle ten- and nuclear chain fibers. If the muscle tension is too great (e.g., sion and contraction (dynamic forces) and muscle length (static overstretching of muscle or too heavy a load), activation of the forces). The nuclear bag fibers respond to both dynamic and static Golgi tendon organ causes a reflex relaxation of the muscle. 77
  • 82. NEUROPHYSIOLOGY Proprioception and Reflex Pathways: III Ib fibers Ia fibers Extrafusal muscle fiber Intrafusal muscle fiber Alpha motor neurons Gamma motor neurons A. Passive stretch. Both intrafusal and extrafusal muscle fibers stretched; spindles activated. Reflex via Ia fibers and alpha motor neurons causes Golgi secondary contraction (basis of stretch reflexes, such as knee jerk). tendon Stretch is too weak to activate Golgi tendon organs organ Ib fibers Alpha activation from brain Ia fibers Extrafusal muscle fiber Intrafusal muscle fiber Inhibitory interneuron Alpha motor neurons Gamma motor neurons B. Active contraction. Central excitation of alpha motor neurons only causes contraction of extrafusal muscle fibers with consequent relaxation of intrafusal fibers; spindles not activated. Tension is low; does not adjust to increased resistance. Tendon organ activated, Golgi causing relaxation tendon organ Alpha and gamma Ib fibers activation from brain Ia fibers Extrafusal muscle fiber Intrafusal muscle fiber Alpha motor neurons Gamma motor neurons C. Active contraction with gamma coactivation. Intrafusal as well as Golgi extrafusal fibers contract; spindles activated, reinforcing contraction tendon stimulus via Ia fibers in accord with resistance. Tendon organ organ activated, causing relaxation if load is too great © FIGURE 2.27 PROPRIOCEPTIVE REFLEX CONTROL MUSCLE TENSION• OF Interaction of the muscle spindle and Golgi tendon organ during passive stretch of a muscle (panel A) and during a contraction (panels B and C). 78
  • 83. NEUROPHYSIOLOGY Proprioception and Reflex Pathways: IV B. Stretch reflex (reciprocal inhibition) A. Afferent inhibition From extensor spindle From extensor spindle receptor (Ia, II fibers) receptor (Ia, II fibers) From flexor spindle (Ia, II fibers) Axosomatic or axodendritic inhibitory synapse Axoaxonic presynaptic Excitatory inhibitory synapse synapse To extensors To extensors To flexors C. Recurrent inhibition D. Tendon organ reflex From extensor tendon organ (Ib fibers) Inhibitory synapse Renshaw cells Excitatory synapse Collaterals To extensors To synergistic muscles To flexors E. Flexor withdrawal reflex Nociceptive fibers Ipsilateral Contralateral flexion extension Inhibitory synapse Excitatory synapse Excitatory synapse Inhibitory synapse To extensors To extensors To flexors To flexors © FIGURE 2.28 SPINAL REFLEX PATHWAYS• Summary of the spinal reflex pathways. 79
  • 84. NEUROPHYSIOLOGY Sensory Pathways: I Cerebral cortex: postcentral gyrus Posterior limb of internal capsule Ventral posterolateral (VPL) nucleus of thalamus Mesencephalon (cerebral peduncles) Medial lemniscus Gracile nucleus Spinothalamic tract Cuneate nucleus Lower part of medulla oblongata Fasciculus gracilis Fasciculus cuneatus Reticular formation Dorsal (posterior) spinal root ganglion Proprioception, Large position myelinated Cervical part Touch, fibers of spinal cord pressure, vibration Small Lateral Pain, myelinated spinothalamic tract: temperature and unmyelin- pain, temperature ated fibers Lateral cervical nucleus Ventral (anterior) spinothalamic tract: Spinocervical tract touch, pressure Lumbar part of spinal cord © FIGURE 2.29 SOMESTHETIC SYSTEM BODY• OF THE Pain, temperature, and pressure sensations below the head ulti- sations to the thalamus (ventral posterolateral nucleus), whereas mately are conveyed to the primary somatosensory cortex (post- the lateral cervical system mediates some touch, vibratory, and central gyrus) by the anterolateral system (spinothalamic and spin- proprioceptive sensations (blue and purple lines show these dual oreticular tracts). The fasciculus gracilis and cuneatus of the spinal pathways). Ultimately, these fibers ascend as parallel pathways to lemniscal system convey proprioceptive, vibratory, and tactile sen- the thalamus, synapse, and ascend to the cortex. 80
  • 85. NEUROPHYSIOLOGY Sensory Pathways: II Cerebral cortex: postcentral gyrus Ventral posteromedial (VPM) nucleus of thalamus Internal capsule Midbrain Dorsal trigeminal lemniscus (cerebral peduncles) Trigeminal mesencephalic nucleus Trigeminal motor nucleus Ventral trigeminal Principal sensory trigeminal nucleus lemniscus Touch, pressure Pontine Pain, temperature reticular Proprioception formation Trigeminal (semilunar) ganglion Ophthalmic n. Maxillary n. Pons Sensory root and Motor root of mandibular n. Medullary reticular formation Spinal trigeminal tract Spinal trigeminal nucleus Cervical part of spinal Facial (VII) n. cord Vagus (X) n. Dorsolateral fasciculus (of Lissauer) Substantia gelatinosa (Iamina II) © FIGURE 2.30 SOMESTHETIC SYSTEM HEAD• OF THE Nerve cells bodies for touch, pressure, pain, and temperature in of CN V (purple fibers). Most relay neurons project to the con- the head are in the trigeminal (semilunar) ganglion of the trigemi- tralateral VPM nucleus of the thalamus and thence to the postcen- nal (CN V) nerve (blue and red lines in figure). Neuronal cell bod- tral gyrus of the cerebral cortex, where they are somatotopically ies mediating proprioception reside in the mesencephalic nucleus represented. 81
  • 86. NEUROPHYSIOLOGY Sensory Pathways: III Schematic demarcation of dermatomes shown as distinct C2 segments. There is actually considerable overlap between C3 any two adjacent dermatomes C4 C2 C5 C3 C6 C4 C7 C5 T1 C8 T1 T2 T3 T2 T4 T3 C6 T5 C6 T4 T6 T5 T7 T1 T8 T6 T9 C5 T7 T10 T11 T8 C8 T12 T9 C7 L1 L2 T10 L3 L4 T11 C6 L5 T12 S1 S2 C8 C7 C8 L1 C7 S2, 3 L2 S3 S4 S1 S5 L3 S2 L5 L4 L1 L2 L3 L5 S1 S2 L4 S1 S1 L5 L5 L4 L4 Levels of principal dermatomes T10 Level of umbilicus C5 Clavicles T12 Inguinal or groin regions C5, 6, 7 Lateral parts of upper limbs L1, 2, 3, 4 Anterior and inner surfaces of lower limbs C8, T1 Medial sides of upper limbs L4, 5, S1 Foot C6 Thumb L4 Medial side of great toe C6, 7, 8 Hand S1, 2, L5 Posterior and outer surfaces of lower limbs C8 Ring and little fingers S1 Lateral margin of foot and little toe T4 Level of nipples S2, 3, 4 Perineum © FIGURE 2.31 DERMATOMES• Sensory information below the head is localized to specific areas dorsal root is called a dermatome. This figure shows the der- of the body, which reflect the distribution of peripheral sensory matome segments and lists key dermatome levels used by clini- fibers that convey sensations to the spinal cord through the dorsal cians. Variability and overlap occur, so all dermatome segments roots (sensory nerve cell bodies reside in the corresponding dorsal are only approximations. root ganglion). The area of skin subserved by afferent fibers of one 82
  • 87. NEUROPHYSIOLOGY Visual System: Receptors Inner limiting B. Section A. Eyeball membrane through retina Axons at surface Lens of retina passing Iris Cornea via optic nerve, Suspensory chiasm, and tract Ciliary ligament to lateral body geniculate body Ganglion cell Anterior Posterior Müller cell chamber chamber (supporting glial Ora containing cell) serrata aqueous humor Amacrine cell Bipolar cell Vitreous humor Horizontal cell Rod Cone Retina Pigment cells Choroid of choroid Sclera Fovea Optic nerve Synaptic ending Synaptic fully ending polarized depolarized Synaptic bar C. Rod in dark D. Rod in light Nucleus Photons of light Rhodopsin Lumirhodopsin Metabolic Metarhodopsin energy Centriole (basal body) Current Retinene Retinene flow + + Opsin Opsin Na+ Na+ Vitamin A permeability Vitamin A permeability decreased increased Circulation © FIGURE 2.32 VISUAL RECEPTORS• The rods and cones of the retina transduce light into electrical sig- dark the cell is depolarized, but it is hyperpolarized in the light. nals. As illustrated for the rod, light is absorbed by rhodopsin, and This electrical response to light is distinct from other receptor through the second messenger cGMP (not shown), Na channels responses, in which the response to a stimulus results in a depolar- in the membrane close and the cell hyperpolarizes. Thus, in the ization of the receptor cell membrane. 83
  • 88. NEUROPHYSIOLOGY Visual System: Visual Pathway Central darker circle represents G macular G zone Overlapping Lightest visual fields A shades A represent B B monocular H H fields Each quadrant a different color Projection on Projection on R RC C left retina right retina Optic P P (II) nerves Choroid Choroid Optic chiasm Periphery Macula Structure of retina (schematic): Projection on right Projection on left A Amacrine cells dorsal lateral dorsal lateral B Bipolar cells geniculate nucleus geniculate nucleus Optic tracts C Cones G Ganglion cells Lateral H Horizontal cells geniculate P Pigment cells bodies R Rods Calcarine fissure Projection Projection on left on right occipital lobe occipital lobe © FIGURE 2.33 RETINOGENICULOSTRIATE VISUAL PATHWAY• The retina has two types of photoreceptors: cones that mediate optic chiasm while information from the temporal retina remains in color vision and rods that mediate light perception but with low the ipsilateral optic tract. Fibers synapse in the lateral geniculate acuity. The greatest acuity is found in the region of the macula of nucleus (visual field is topographically represented here and the retina, where only cones are found (upper left panel). Visual inverted), and signals are conveyed to the visual cortex on the signals are conveyed by the ganglion cells whose axons course in medial surface of the occipital lobe. the optic nerves. Visual signals from the nasal retina cross in the 84
  • 89. NEUROPHYSIOLOGY Auditory System: Cochlea Cochlear nerve A. Membranous Semicircular Utricle labyrinth within canals bony labyrinth Saccule (path of sound waves) Scala vestibuli Cochlear duct (scala media) Round window Oval window and stapes Scala tympani B. Section through turn Vestibular (Reissner’s) of cochlea Scala vestibuli membrane (perilymph); Cochlear duct (scala media; weakly endolymph) +80 mV positive Efferent Tectorial membrane nerve fibers Spiral ligament Bone Scala tympani Afferent Outer hair cells; 60 mV (perilymph); 0 mV nerve fibers Basilar membrane Spiral ganglion Inner hair cell; 60 mV C. Spiral organ Hair cells of Corti Tectorial membrane Inner Outer Stereocilia Rods and tunnel of Corti Basilar membrane Supporting cells Afferent nerve fibers Spiral lamina Spiral ganglion Efferent nerve fibers As basilar membrane moves up, hairs are deflected outward, causing depolarization of hair cells and increased firing of afferent nerve fibers © FIGURE 2.34 COCHLEAR RECEPTORS• The cochlea transduces sound into electrical signals. This is response to pressure changes imparted on the oval window of the accomplished by the hair cells, which depolarize in response to cochlea in response to vibrations of the tympanic membrane. vibration of the basilar membrane. The basilar membrane moves in 85
  • 90. NEUROPHYSIOLOGY Auditory System: Pathways Acoustic area of temporal lobe cortex Medial geniculate body Brachium of inferior colliculus Inferior colliculus Midbrain Correspondence between cochlea and acoustic area of cortex: Low tones Lateral Middle tones lemnisci High tones Nuclei of lateral Medulla lemnisci oblongata Dorsal cochlear nucleus Inferior cerebellar peduncle Ventral cochlear nucleus Cochlear division of vestibulocochlear nerve Dorsal acoustic stria Inner Outer Reticular formation Trapezoid body Spiral ganglion Hair cells Intermediate acoustic stria Superior olivary complex © FIGURE 2.35 AUDITORY PATHWAYS• The cochlea transduces sound into electrical signals. Axons convey geniculate bodies) and then the acoustic cortex in the transverse these signals to the dorsal and ventral cochlear nuclei, where it is gyrus of the temporal lobe, where information is tonotopically rep- tonotopically organized. Following a series of integrated relay resented (low, middle, and high tones). pathways, the ascending pathway projects to the thalamus (medial 86
  • 91. NEUROPHYSIOLOGY Vestibular System: Receptors A. Membranous labyrinth Superior semi- Vestibular ganglion circular canal Vestibular Cristae within and cochlear ampullae divisions of vestibulocochlear n. Horizontal semi- circular canal Maculae Saccule Posterior semi- Utricle circular canal Cochlear duct (scala media) B. Section of crista Opposite wall of ampulla C. Section of macula Gelatinous cupula Hair tufts Otoconia Hair cells Gelatinous otolithic membrane Nerve fibers Hair tuft Basement Hair cells membrane Supporting cells Basement membrane Nerve fibers Excitation D. Structure and innervation of hair cells Inhibition Kinocilium Kinocilium Stereocilia Basal body Stereocilia Cuticle Cuticle Basal body Hair cell (type I) Hair cell (type II) Supporting cells Supporting cell Afferent nerve Efferent nerve calyx endings Afferent nerve Efferent nerve endings ending Myelin sheath Basement membrane Myelin sheath © FIGURE 2.36 VESTIBULAR RECEPTORS• The vestibular apparatus detects movement of the head in the form such as the pull of gravity. The three semicircular canals are of linear and angular acceleration. This information is important for aligned so that the angular movement of the head can be sensed in the control of eye movements so that the retina can be provided all planes. The sensory hair cells are located in the maculae of the with a stable visual image. It is also important for the control of utricle and saccule and in the cristae within each ampullae. posture. The utricle and saccule respond to linear acceleration, 87
  • 92. NEUROPHYSIOLOGY Vestibular System: Vestibulospinal Tracts Excitatory endings Superior Inhibitory Medial endings Vestibular nuclei Lateral Inferior Rostral Ascending fibers in medial Upper longitudinal fasciculi Trunk limb Ventral Dorsal To Lower cerebellum limb Caudal Somatotopical pattern in lateral vestibular nucleus Vestibular ganglion and nerve Motor neuron (controlling neck muscles) Fibers from cristae Medial vestibulo- Lateral (rotational stimuli) spinal fibers in medial vestibulospinal longitudinal fasciculi tract Excitatory Excitatory interneuron endings to back Inhibitory muscles ? interneuron ? Fibers from maculae (gravitational stimuli) Lower part of To flexor muscles cervical To extensor muscles spinal cord Inhibitory ending ? ? To axial muscles To axial Inhibitory muscles Excitatory ending ending Lateral vestibulospinal tract Lumbar part of spinal cord Inhibitory interneuron Excitatory synapse To flexor muscles To extensor muscles © FIGURE 2.37 VESTIBULOSPINAL TRACTS• Sensory input from the vestibular apparatus is used to maintain sta- cord (muscle control), cerebellum (vermis), reticular formation bility of the head and to maintain balance and posture. Axons con- (vomiting center), extraocular muscles, and cortex (conscious per- vey vestibular information to the vestibular nuclei in the pons, and ception). This figure shows only the spinal cord pathways. then secondary axons distribute this information to five sites: spinal 88
  • 93. NEUROPHYSIOLOGY Gustatory (Taste) System: Receptors A. Tongue B. Section through Foliate vallate papillae papilla Taste buds Duct of gustatory (Ebner’s) gland C. Taste bud Epithelium Fungiform Basement membrane Vallate papillae papillae Nerve plexus Microvilli Nerve fibers emerging from Taste pore taste buds Taste cells Desmosomes Large nerve fiber Basement membrane Fibroblast Epithelium Granules Small nerve fiber Schwann cell Intercellular space Large nerve fiber Collagen Microvilli D. Detail of taste pore E. Detail of base of receptor cells © FIGURE 2.38 TASTE RECEPTORS• Taste buds on the tongue respond to various chemical stimuli. Taste larize neurons connected to the taste cells. A single taste bud can cells, like neurons, normally have a net negative charge internally respond to more than one stimulus. The four traditional taste qualities and are depolarized by stimuli, thus releasing transmitters that depo- that are sensed are sweet, salty, sour, and bitter. 89
  • 94. NEUROPHYSIOLOGY Gustatory (Taste) System: Pathways Ventral posteromedial (VPM) nucleus of thalamus Sensory cortex (just below face area) Lateral hypothalamic area Amygdala Mesencephalic Pontine taste area nucleus and Trigeminal (V) n. Motor nucleus of trigeminal n. Maxillary n. Mandibular n. Pons Pterygo- palatine Greater petrosal n. ganglion Geniculate ganglion Otic Facial (VII) n. ganglion and Lingual n. Nervus inermedius Rostral part of nucleus Chorda of solitary tract tympani Glossopharyngeal (IX) n. Fungiform papillae Foliate papillae Lower part of Valiate papillae medulla oblongata Petrosal (inferior) Epiglottis ganglion of Larynx glossopharyngeal n. Nodose (inferior) ganglion of vagus n. Superior laryngeal n. Vagus (X) n. © FIGURE 2.39 TASTE PATHWAYS• Depicted here are the afferent pathways leading from the taste receptors to the brainstem and, ultimately, to the sensory cortex in the postcentral gyrus. 90
  • 95. NEUROPHYSIOLOGY Olfactory System: Receptors Cribriform plate Olfactory A. Distribution of ethmoid bone bulb of olfactory epithelium (blue area) Lateral nasal wall Septum B. Schema of section through olfactory mucosa Cribriform plate Schwann cell Olfactory gland Unmyelinated olfactory axons Basement membrane Sustentacular cells Endoplasmic reticulum Nucleus Olfactory cells Dendrites Terminal bars (desmosomes) Olfactory rod (vesicle) Villi Cilia Mucus © FIGURE 2.40 OLFACTORY RECEPTORS• The sensory cells that make up the olfactory epithelium respond to qualities that can be sensed: floral, ethereal (e.g., pears), musky, odorants by depolarizing. Like taste buds, an olfactory cell can camphor (e.g., eucalyptus), putrid, and pungent (e.g., vinegar, pep- respond to more than one odorant. There are six general odor permint). 91
  • 96. NEUROPHYSIOLOGY Olfactory System: Pathway Efferent fibers Afferent fibers Granule cell (excited by Fibers from contralateral olfactory bulb and inhibiting to mitral Fibers to contralateral olfactory bulb and tufted cells) Mitral cell Anterior commissure Recurrent process Medial olfactory stria Tufted cell Periglom- Olfactory trigone and erular cell olfactory tubercle Glomerulus Anterior perforated substance Olfactory nerve fibers Lateral olfactory stria Lateral olfactory tract nucleus Piriform lobe Uncus Amygdala (in phantom) Entorhinal area Olfactory epithelium Olfactory tract Olfactory nerves Anterior olfactory nucleus Olfactory bulb Cribriform plate of ethmoid bone © FIGURE 2.41 OLFACTORY PATHWAY• Olfactory stimuli are detected by the nerve fibers of the olfactory sure (some efferent projections course to the contralateral olfactory epithelium and conveyed to the olfactory bulb (detailed local cir- bulb, blue lines) or terminate in the ipsilateral olfactory trigone cuitry shown in upper left panel). Integrated signals pass along the (olfactory tubercle). Axons then project to the primary olfactory olfactory tract and centrally diverge to pass to the anterior commis- cortex (piriform cortex), entorhinal cortex, and amygdala. 92
  • 97. Installing Adobe Acrobat Reader 5.0 The images and text included in this atlas are contained in a Portable Document Format (pdf) file and can be viewed with Adobe Acrobat Reader. A copy of Acrobat Reader 5.0 is included on this CD. You will need to install or upgrade to Acrobat Reader 5.0 in order to have full functionality. Please follow these instructions: 1. Choose Run from the Start menu and then click Browse. 2. Double-click the InstallAcrobat.exe file to open the Reader Installer. 3. Follow the onscreen instructions. Running the Atlas of Neuroanatomy and Neurophysiology Windows 1. Insert the CD into the CD-ROM drive. 2. If Acrobat Reader 5.0 is not already installed on your computer, follow the installation instructions above. 3. Choose Run from the Start menu and type x: (where x is the letter of your CD- ROM drive). 4. Under Files of Type, click All Files. 5. Double-click the Neuro Atlas.pdf file to open the program. 6. For best viewing results, use the Edit menu to access the Preferences. Select General and open the Display preferences to activate the Smooth Line Art option. Macintosh 1. Insert the CD into the CD-ROM drive. 2. If Acrobat Reader 5.0 is not already installed on your computer, follow the installation instructions above. 3. Double-click the Neuro Atlas.pdf file to open the program. 4. For best viewing results, use the Edit menu to access the Preferences. Select General and open the Display preferences to activate the Smooth Line Art option. All rights reserved. No material on this CD-ROM may be reproduced in any elec- tronic format, including information storage and retrieval systems, without permis- sion in writing from the publisher. Send requests for permissions to Permissions Editor, Icon Custom Communications, 295 North St., Teterboro NJ 07608, or visit