Nervous System


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Nervous System

  1. 1. PowerPoint Lecture Outlines to accompany Hole’s Human Anatomy and Physiology Eleventh Edition Shier  Butler  Lewis Chapter 11 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  2. 2. Chapter 11 Nervous System II <ul><li>Meninges </li></ul><ul><ul><li>membranes surrounding CNS </li></ul></ul><ul><ul><li>protect CNS </li></ul></ul><ul><ul><li>three layers </li></ul></ul><ul><ul><ul><li>dura mater – outer, tough </li></ul></ul></ul><ul><ul><ul><li>arachnoid mater – thin, weblike </li></ul></ul></ul><ul><ul><ul><li>pia mater – inner, very thin </li></ul></ul></ul>
  3. 3. Meninges of the Spinal Cord
  4. 4. Ventricles <ul><li>interconnected cavities </li></ul><ul><li>within cerebral hemispheres and brain stem </li></ul><ul><li>continuous with central canal of spinal cord </li></ul><ul><li>filled with cerebrospinal fluid (CSF) </li></ul><ul><li>lateral ventricles </li></ul><ul><li>third ventricle </li></ul><ul><li>fourth ventricle </li></ul><ul><li>cerebral aqueduct </li></ul>
  5. 5. Cerebrospinal Fluid <ul><li>secreted by choroid plexus </li></ul><ul><li>circulates in ventricles, central canal of spinal cord, and subarachnoid space </li></ul><ul><li>completely surrounds brain and spinal cord </li></ul><ul><li>clear liquid </li></ul><ul><li>nutritive and protective </li></ul><ul><li>helps maintain stable ion concentrations in CNS </li></ul>
  6. 6. Spinal Cord <ul><li>slender column of nervous tissue continuous with brain </li></ul><ul><li>extends downward through vertebral canal </li></ul><ul><li>begins at level of foramen magnum and terminates near first and second lumbar </li></ul>
  7. 7. Cross Section of Spinal Cord
  8. 8. Functions of Spinal Cord <ul><li>center for spinal reflexes </li></ul><ul><li>conduit for nerve impulses to and from the brain </li></ul>
  9. 9. Reflex Arcs Reflexes – automatic, subconscious responses to stimuli within or outside the body
  10. 10. Reflex Arcs
  11. 11. General Components of a Spinal Reflex
  12. 12. Reflex Behavior <ul><li>example is the knee-jerk reflex </li></ul><ul><li>simple monosynaptic reflex </li></ul><ul><li>helps maintain an upright posture </li></ul>
  13. 13. Reflex Behavior <ul><li>example is a withdrawal reflex </li></ul><ul><li>prevents or limits tissue damage </li></ul>
  14. 14. Reflex Arc <ul><li>example crossed extensor reflex </li></ul><ul><li>crossing of sensory impulses within the reflex center </li></ul><ul><li>to produce an opposite effect </li></ul>
  15. 15. Tracts of the Spinal Cord <ul><li>Ascending tracts conduct sensory impulses to the brain </li></ul><ul><li>Descending tracts conduct motor impulses from the brain to motor neurons reaching muscles and glands </li></ul>
  16. 16. Ascending Tracts <ul><li>major ascending spinal cord tracts </li></ul><ul><ul><li>fasciculus gracilis and fasciculus cuneatus </li></ul></ul><ul><ul><li>spinothalamic </li></ul></ul><ul><ul><ul><li>lateral and anterior </li></ul></ul></ul><ul><ul><li>spinocerebellar </li></ul></ul><ul><ul><ul><li>posterior and anterior </li></ul></ul></ul>
  17. 17. Descending Tracts <ul><li>major descending spinal cord tracts </li></ul><ul><ul><li>corticospinal </li></ul></ul><ul><ul><ul><li>lateral and anterior </li></ul></ul></ul><ul><ul><li>reticulospinal </li></ul></ul><ul><ul><ul><li>lateral, anterior and medial </li></ul></ul></ul><ul><ul><li>rubrospinal </li></ul></ul>
  18. 18. Nerve Tracts of the Spinal Cord
  19. 19. Brain <ul><li>Functions </li></ul><ul><ul><li>interprets sensations </li></ul></ul><ul><ul><li>determines perception </li></ul></ul><ul><ul><li>stores memory </li></ul></ul><ul><ul><li>reasoning </li></ul></ul><ul><ul><li>makes decisions </li></ul></ul><ul><ul><li>coordinates muscular movements </li></ul></ul><ul><ul><li>regulates visceral activities </li></ul></ul><ul><ul><li>determines personality </li></ul></ul><ul><li>Major Parts </li></ul><ul><ul><li>cerebrum </li></ul></ul><ul><ul><ul><li>two hemispheres </li></ul></ul></ul><ul><ul><li>basal nuclei </li></ul></ul><ul><ul><li>diencephalon </li></ul></ul><ul><ul><li>brainstem </li></ul></ul><ul><ul><li>cerebellum </li></ul></ul>
  20. 20. Brain
  21. 21. Brain Development <ul><li>Three Major Vesicles </li></ul><ul><li>Forebrain </li></ul><ul><li>Midbrain </li></ul><ul><li>Hindbrain </li></ul>
  22. 22. Brain Development
  23. 23. Structure of Cerebrum <ul><li>corpus callosum </li></ul><ul><ul><li>connects cerebral hemispheres </li></ul></ul><ul><li>convolutions </li></ul><ul><ul><li>bumps or gyri </li></ul></ul><ul><li>sulci </li></ul><ul><ul><li>grooves </li></ul></ul><ul><li>longitudinal fissure </li></ul><ul><ul><li>separates hemispheres </li></ul></ul><ul><li>transverse fissure </li></ul><ul><ul><li>separates cerebrum from cerebellum </li></ul></ul>
  24. 24. Lobes of Cerebral Hemispheres <ul><li>Frontal </li></ul><ul><li>Parietal </li></ul><ul><li>Temporal </li></ul><ul><li>Occipital </li></ul><ul><li>Insula </li></ul>
  25. 25. Functions of the Cerebrum <ul><li>interpreting impulses </li></ul><ul><li>initiating voluntary movements </li></ul><ul><li>storing information as memory </li></ul><ul><li>retrieving stored information </li></ul><ul><li>reasoning </li></ul><ul><li>seat of intelligence and personality </li></ul>
  26. 26. Functional Regions of Cerebral Cortex Cerebral Cortex – thin layer of gray matter that constitutes the outermost portion of cerebrum; contains 75% of all neurons in nervous system
  27. 27. Sensory Areas <ul><li>Cutaneous Sensory Area </li></ul><ul><ul><li>parietal lobe </li></ul></ul><ul><ul><li>interprets sensations on skin </li></ul></ul><ul><li>Visual Area </li></ul><ul><ul><li>occipital lobe </li></ul></ul><ul><ul><li>interprets vision </li></ul></ul><ul><li>Auditory Area </li></ul><ul><ul><li>temporal lobe </li></ul></ul><ul><ul><li>interprets hearing </li></ul></ul><ul><li>Sensory Area for Taste </li></ul><ul><ul><li>near bases of the central sulci </li></ul></ul><ul><ul><li>Sensory Area for Smell </li></ul></ul><ul><ul><ul><ul><ul><li>arise from centers deep within the cerebrum </li></ul></ul></ul></ul></ul>
  28. 28. Sensory Areas
  29. 29. Association Areas <ul><li>regions that are not primary motor or primary sensory areas </li></ul><ul><li>widespread throughout the cerebral cortex </li></ul><ul><li>analyze and interpret sensory experiences </li></ul><ul><li>provide memory, reasoning, verbalization, judgment, emotions </li></ul>
  30. 30. Association Areas <ul><li>Frontal Lobe Association Areas </li></ul><ul><ul><li>concentrating </li></ul></ul><ul><ul><li>planning </li></ul></ul><ul><ul><li>complex problem solving </li></ul></ul><ul><li>Parietal Lobe Association Areas </li></ul><ul><ul><li>understanding speech </li></ul></ul><ul><ul><li>choosing words to express thought </li></ul></ul><ul><li>Temporal Lobe Association Areas </li></ul><ul><ul><li>interpret complex sensory </li></ul></ul><ul><ul><li>experiences </li></ul></ul><ul><ul><li>store memories of visual scenes, </li></ul></ul><ul><ul><li>music, and complex patterns </li></ul></ul><ul><li>Occipital Lobe Association Areas </li></ul><ul><ul><li>analyze and combine visual images with other sensory experiences </li></ul></ul>
  31. 31. Hemisphere Dominance <ul><li>The left hemisphere is dominant is most individuals </li></ul><ul><li>Dominant hemisphere controls </li></ul><ul><ul><li>speech </li></ul></ul><ul><ul><li>writing </li></ul></ul><ul><ul><li>reading </li></ul></ul><ul><ul><li>verbal skills </li></ul></ul><ul><ul><li>analytical skills </li></ul></ul><ul><ul><li>computational skills </li></ul></ul><ul><li>Nondominant hemisphere controls </li></ul><ul><ul><li>nonverbal tasks </li></ul></ul><ul><ul><li>motor tasks </li></ul></ul><ul><ul><li>understanding and interpreting musical and visual patterns </li></ul></ul><ul><ul><li>provides emotional and intuitive thought processes </li></ul></ul>
  32. 32. Memory <ul><li>Short Term </li></ul><ul><ul><li>working memory </li></ul></ul><ul><ul><li>closed neuronal circuit </li></ul></ul><ul><ul><li>circuit is stimulated over and over </li></ul></ul><ul><ul><li>when impulse flow ceases, memory does also </li></ul></ul><ul><ul><ul><li>unless it enters long-term memory via memory consolidation </li></ul></ul></ul><ul><li>Long Term </li></ul><ul><ul><li>changes structure or function of neurons </li></ul></ul><ul><ul><li>enhances synaptic transmission </li></ul></ul>
  33. 33. Motor Areas <ul><li>Primary Motor Areas </li></ul><ul><ul><li>frontal lobes </li></ul></ul><ul><ul><li>control voluntary muscles </li></ul></ul><ul><li>Broca’s Area </li></ul><ul><ul><li>anterior to primary motor cortex </li></ul></ul><ul><ul><li>usually in left hemisphere </li></ul></ul><ul><ul><li>controls muscles needed for speech </li></ul></ul><ul><li>Frontal Eye Field </li></ul><ul><ul><li>above Broca’s area </li></ul></ul><ul><ul><li>controls voluntary movements of eyes and eyelids </li></ul></ul>
  34. 34. Motor Areas
  35. 35. Functions of the Cerebral Lobes
  36. 36. Basal Nuclei <ul><li>masses of gray matter </li></ul><ul><li>deep within cerebral hemispheres </li></ul><ul><li>caudate nucleus , putamen , globus pallidus </li></ul><ul><li>produce dopamine </li></ul><ul><li>control certain muscular activities </li></ul><ul><ul><li>primarily by inhibiting motor functions </li></ul></ul>
  37. 37. Diencephalon <ul><li>between cerebral hemispheres and above the brainstem </li></ul><ul><li>surrounds third ventricle </li></ul><ul><li>thalamus </li></ul><ul><li>hypothalamus </li></ul><ul><li>optic tracts </li></ul><ul><li>optic chiasma </li></ul><ul><li>infundibulum </li></ul><ul><li>posterior pituitary </li></ul><ul><li>mammillary bodies </li></ul><ul><li>pineal gland </li></ul>
  38. 38. Diencephalon <ul><li>Thalamus </li></ul><ul><ul><li>gateway for sensory impulses heading to cerebral cortex </li></ul></ul><ul><ul><li>receives all sensory impulses (except smell) </li></ul></ul><ul><ul><li>channels impulses to appropriate part of cerebral cortex for interpretation </li></ul></ul><ul><li>Hypothalamus </li></ul><ul><ul><li>maintains homeostasis by regulating visceral activities </li></ul></ul><ul><ul><li>links nervous and endocrine systems </li></ul></ul>
  39. 39. Diencephalon <ul><li>Consists of </li></ul><ul><ul><li>portions of frontal lobe </li></ul></ul><ul><ul><li>portions of temporal lobe </li></ul></ul><ul><ul><li>hypothalamus </li></ul></ul><ul><ul><li>thalamus </li></ul></ul><ul><ul><li>basal nuclei </li></ul></ul><ul><ul><li>other deep nuclei </li></ul></ul><ul><li>Functions </li></ul><ul><ul><li>controls emotions </li></ul></ul><ul><ul><li>produces feelings </li></ul></ul><ul><ul><li>interprets sensory impulses </li></ul></ul>Limbic System
  40. 40. Brain Stem <ul><li>Three Parts </li></ul><ul><li>Midbrain </li></ul><ul><li>Pons </li></ul><ul><li>Medulla Oblongata </li></ul>
  41. 41. Midbrain <ul><li>between diencephalon and pons </li></ul><ul><li>contains bundles of fibers that join lower parts of brainstem and spinal cord with higher part of brain </li></ul><ul><li>cerebral aqueduct </li></ul><ul><li>cerebral peduncles – bundles of nerve fibers </li></ul><ul><li>corpora quadrigemina – centers for visual and auditory reflexes </li></ul>
  42. 42. Pons <ul><li>rounded bulge on underside of brainstem </li></ul><ul><li>between medulla oblongata and midbrain </li></ul><ul><li>helps regulate rate and depth of breathing </li></ul><ul><li>relays nerve impulses to and from medulla oblongata and cerebellum </li></ul>
  43. 43. Medulla Oblongata <ul><li>enlarged continuation of spinal cord </li></ul><ul><li>conducts ascending and descending impulses between brain and spinal cord </li></ul><ul><li>contains cardiac, vasomotor, and respiratory control centers </li></ul><ul><li>contains various nonvital reflex control centers (coughing, sneezing, swallowing, vomiting) </li></ul>
  44. 44. Reticular Formation <ul><li>complex network of nerve fibers scattered throughout the brain stem </li></ul><ul><li>extends into the diencephalon </li></ul><ul><li>connects to centers of hypothalamus, basal nuclei, cerebellum, and cerebrum </li></ul><ul><li>filters incoming sensory information </li></ul><ul><li>arouses cerebral cortex into state of wakefulness </li></ul>
  45. 45. Types of Sleep <ul><li>Slow Wave </li></ul><ul><ul><li>non-REM sleep </li></ul></ul><ul><ul><li>person is tired </li></ul></ul><ul><ul><li>decreasing activity of reticular system </li></ul></ul><ul><ul><li>restful </li></ul></ul><ul><ul><li>dreamless </li></ul></ul><ul><ul><li>reduced blood pressure and respiratory rate </li></ul></ul><ul><ul><li>ranges from light to heavy </li></ul></ul><ul><ul><li>alternates with REM sleep </li></ul></ul><ul><li>Rapid Eye Movement (REM) </li></ul><ul><ul><li>paradoxical sleep </li></ul></ul><ul><ul><li>some areas of brain active </li></ul></ul><ul><ul><li>heart and respiratory rates irregular </li></ul></ul><ul><ul><li>dreaming occurs </li></ul></ul>
  46. 46. Cerebellum <ul><li>inferior to occipital lobes </li></ul><ul><li>posterior to pons and medulla oblongata </li></ul><ul><li>two hemispheres </li></ul><ul><li>vermis connects hemispheres </li></ul><ul><li>cerebellar cortex – gray matter </li></ul><ul><li>arbor vitae – white matter </li></ul><ul><li>cerebellar peduncles – nerve fiber tracts </li></ul><ul><li>dentate nucleus – largest nucleus in cerebellum </li></ul><ul><li>integrates sensory information concerning position of body parts </li></ul><ul><li>coordinates skeletal muscle activity </li></ul><ul><li>maintains posture </li></ul>
  47. 47. Major Parts of the Brain
  48. 48. Peripheral Nervous System <ul><li>Cranial nerves arising from the brain </li></ul><ul><ul><li>Somatic fibers connecting to the skin and skeletal muscles </li></ul></ul><ul><ul><li>Autonomic fibers connecting to viscera </li></ul></ul><ul><li>Spinal nerves arising from the spinal cord </li></ul><ul><ul><li>Somatic fibers connecting to the skin and skeletal muscles </li></ul></ul><ul><ul><li>Autonomic fibers connecting to viscera </li></ul></ul>
  49. 49. Nervous System Subdivisions
  50. 50. Structure of a Peripheral Nerve
  51. 51. Nerve Fiber Classification <ul><li>Sensory Nerves – conduct impulses into brain or spinal cord </li></ul><ul><li>Motor Nerves – conduct impulses to muscles or glands </li></ul><ul><li>Mixed Nerves – contain both sensory nerve fibers and motor nerve fibers; most nerves </li></ul>
  52. 52. Nerve Fiber Classification <ul><li>General somatic efferent fibers </li></ul><ul><ul><li>carry motor impulses from CNS to skeletal muscles </li></ul></ul><ul><li>General visceral efferent fibers </li></ul><ul><ul><li>carry motor impulses away from CNS to smooth muscles and glands </li></ul></ul><ul><li>General somatic afferent fibers </li></ul><ul><ul><li>carry sensory impulses to CNS from skin and skeletal muscles </li></ul></ul><ul><li>General visceral afferent fibers </li></ul><ul><ul><li>carry sensory impulses to CNS from blood vessels and internal organs </li></ul></ul>
  53. 53. Nerve Fiber Classification <ul><li>Special somatic efferent fibers </li></ul><ul><ul><li>carry motor impulses from brain to muscles used in chewing, swallowing, speaking, and forming facial expressions </li></ul></ul><ul><li>Special visceral afferent fibers </li></ul><ul><ul><li>carry sensory impulses to brain from olfactory and taste receptors </li></ul></ul><ul><li>Special somatic afferent fibers </li></ul><ul><ul><li>carry sensory impulses to brain from receptors of sight, hearing, and equilibrium </li></ul></ul>
  54. 54. Cranial Nerves
  55. 55. Cranial Nerves I and II <ul><li>Olfactory (I) </li></ul><ul><ul><li>sensory </li></ul></ul><ul><ul><li>fibers transmit impulses associated with smell </li></ul></ul><ul><li>Optic (II) </li></ul><ul><ul><li>sensory </li></ul></ul><ul><ul><li>fibers transmit impulses associated with vision </li></ul></ul>
  56. 56. Cranial Nerves III and IV <ul><li>Trochlear (IV) </li></ul><ul><ul><li>some sensory </li></ul></ul><ul><ul><ul><li>proprioreceptors </li></ul></ul></ul><ul><ul><li>primarily motor </li></ul></ul><ul><ul><li>motor impulses to muscles that move the eyes </li></ul></ul><ul><li>Oculomotor (III) </li></ul><ul><ul><li>some sensory </li></ul></ul><ul><ul><ul><li>proprioreceptors </li></ul></ul></ul><ul><ul><li>primarily motor </li></ul></ul><ul><ul><li>motor impulses to muscles that </li></ul></ul><ul><ul><ul><li>raise eyelids </li></ul></ul></ul><ul><ul><ul><li>move the eyes </li></ul></ul></ul><ul><ul><ul><li>focus lens </li></ul></ul></ul><ul><ul><ul><li>adjust light entering eye </li></ul></ul></ul>
  57. 57. Cranial Nerve V <ul><li>Trigeminal (V) </li></ul><ul><ul><li>mixed </li></ul></ul><ul><ul><li>opthalmic division </li></ul></ul><ul><ul><ul><li>sensory from surface of eyes, tear glands, scalp, forehead, and upper eyelids </li></ul></ul></ul><ul><ul><li>maxillary division </li></ul></ul><ul><ul><ul><li>sensory from upper teeth, upper gum, upper lip, palate, and skin of face </li></ul></ul></ul><ul><ul><li>mandibular division </li></ul></ul><ul><ul><ul><li>sensory from scalp, skin of jaw, lower teeth, lower gum, and lower lip </li></ul></ul></ul><ul><ul><ul><li>motor to muscles of mastication and muscles in floor of mouth </li></ul></ul></ul>
  58. 58. Cranial Nerves VI and VII <ul><li>Abducens (VI) </li></ul><ul><ul><li>primarily motor </li></ul></ul><ul><ul><li>motor impulses to muscles that move the eyes </li></ul></ul><ul><ul><li>some sensory with proprioreceptors </li></ul></ul><ul><li>Facial (VII) </li></ul><ul><ul><li>mixed </li></ul></ul><ul><ul><li>sensory from taste receptors </li></ul></ul><ul><ul><li>motor to muscles of facial expression, tear glands, and salivary glands </li></ul></ul>
  59. 59. Cranial Nerves VIII and IX <ul><li>Vestibulocochlear (VIII) </li></ul><ul><ul><li>sensory </li></ul></ul><ul><ul><li>vestibular branch </li></ul></ul><ul><ul><ul><li>sensory from equilibrium receptors of ear </li></ul></ul></ul><ul><ul><li>cochlear branch </li></ul></ul><ul><ul><ul><li>sensory from hearing receptors </li></ul></ul></ul><ul><li>Glossopharyngeal (IX) </li></ul><ul><ul><li>mixed </li></ul></ul><ul><ul><li>sensory from pharynx, tonsils, tongue, and carotid arteries </li></ul></ul><ul><ul><li>motor to salivary glands and muscles of pharynx </li></ul></ul>
  60. 60. Cranial Nerve X <ul><li>Vagus (X) </li></ul><ul><ul><li>mixed </li></ul></ul><ul><ul><li>somatic motor to muscles of speech and swallowing </li></ul></ul><ul><ul><li>autonomic motor to viscera of thorax and abdomen </li></ul></ul><ul><ul><li>sensory from pharynx, larynx, esophagus, and viscera of thorax and abdomen </li></ul></ul>
  61. 61. Cranial Nerves XI and XII <ul><li>Accessory (XI) </li></ul><ul><ul><li>primarily motor </li></ul></ul><ul><ul><li>cranial branch </li></ul></ul><ul><ul><ul><li>motor to muscles of soft palate, pharynx, and larynx </li></ul></ul></ul><ul><ul><li>spinal branch </li></ul></ul><ul><ul><ul><li>motor to muscles of neck, and back; some proprioreceptor </li></ul></ul></ul><ul><li>Hypoglossal (XII) </li></ul><ul><ul><li>primarily motor </li></ul></ul><ul><ul><li>motor to muscles of the tongue; some proprioreceptor </li></ul></ul>
  62. 62. Functions of Cranial Nerves
  63. 63. Spinal Nerves <ul><li>mixed nerves </li></ul><ul><li>31 pairs </li></ul><ul><ul><li>8 cervical </li></ul></ul><ul><ul><ul><li>(C1 to C8) </li></ul></ul></ul><ul><ul><li>12 thoracic </li></ul></ul><ul><ul><ul><li>(T1 to T12) </li></ul></ul></ul><ul><ul><li>5 lumbar </li></ul></ul><ul><ul><ul><li>(L1 to L5) </li></ul></ul></ul><ul><ul><li>5 sacral </li></ul></ul><ul><ul><ul><li>(S1 to S5) </li></ul></ul></ul><ul><ul><li>1 coccygeal </li></ul></ul><ul><ul><ul><li>(Co) </li></ul></ul></ul>
  64. 64. Spinal Nerves <ul><li>Dorsal root (posterior or sensory root) </li></ul><ul><ul><li>axons of sensory neurons in the dorsal root ganglion </li></ul></ul><ul><li>Dorsal root ganglion </li></ul><ul><ul><li>cell bodies of sensory neurons whose axons conduct impulses inward from peripheral body parts </li></ul></ul>
  65. 65. Dermatome <ul><li>an area of skin that the sensory nerve fibers of a particular spinal nerve innervate </li></ul>
  66. 66. Spinal Nerves <ul><li>Ventral root (anterior or motor root) </li></ul><ul><ul><li>axons of motor neurons whose cell bodies are in spinal cord </li></ul></ul><ul><li>Spinal nerve </li></ul><ul><ul><li>union of ventral root and dorsal root </li></ul></ul>
  67. 67. Cervical Plexuses Nerve plexus – complex networks formed by anterior branches of spinal nerves; fibers of various spinal nerves are sorted and recombined <ul><li>Cervical Plexus </li></ul><ul><ul><li>formed by anterior branches of C1-C4 </li></ul></ul><ul><ul><li>lies deep in the neck </li></ul></ul><ul><ul><li>supply muscles and skin of the neck </li></ul></ul><ul><ul><li>C3 – C5 contribute to phrenic nerves </li></ul></ul>
  68. 68. Brachial Plexuses <ul><li>C5-T1 </li></ul><ul><li>lies deep within shoulders </li></ul><ul><li>musculocutaneous nerves </li></ul><ul><ul><li>supply muscles of anterior arms and skin of forearms </li></ul></ul><ul><li>ulnar and median nerves </li></ul><ul><ul><li>supply muscles of forearms and hands </li></ul></ul><ul><ul><li>supply skin of hands </li></ul></ul><ul><li>radial nerves </li></ul><ul><ul><li>supply posterior muscles of arms and skin of forearms and hands </li></ul></ul><ul><li>axillary nerves </li></ul><ul><ul><li>supply muscles and skin of anterior, lateral, and posterior arms </li></ul></ul>
  69. 69. Lumbosacral Plexuses <ul><li>T12 – S5 </li></ul><ul><li>extend from lumbar region into pelvic cavity </li></ul><ul><li>obturator nerves </li></ul><ul><ul><li>supply motor impulses to adductors of thighs </li></ul></ul><ul><li>femoral nerves </li></ul><ul><ul><li>supply motor impulses to muscles of anterior thigh and sensory impulses from skin of thighs and legs </li></ul></ul><ul><li>sciatic nerves </li></ul><ul><ul><li>supply muscles and skin of thighs, legs, and feet </li></ul></ul>
  70. 70. Plexuses
  71. 71. Autonomic Nervous System <ul><li>functions without conscious effort </li></ul><ul><li>controls visceral activities </li></ul><ul><li>regulates smooth muscle, cardiac muscle, and glands </li></ul><ul><li>efferent fibers typically lead to ganglia outside CNS </li></ul><ul><li>Two Divisions </li></ul><ul><ul><li>sympathetic – prepares body for fight or flight situations </li></ul></ul><ul><ul><li>parasympathetic – prepares body for resting and digesting activities </li></ul></ul>
  72. 72. Autonomic Nerve Fibers <ul><li>all are neurons are motor (efferent) </li></ul><ul><li>preganglionic fibers </li></ul><ul><ul><li>axons of preganglionic neurons </li></ul></ul><ul><ul><li>neuron cell bodies in CNS </li></ul></ul><ul><li>postganglionic fibers </li></ul><ul><ul><li>axons of postganglionic neurons </li></ul></ul><ul><ul><li>neuron cell bodies in ganglia </li></ul></ul>
  73. 73. Sympathetic Division <ul><li>thoracolumbar divison – location of preganglionic neurons </li></ul><ul><li>preganglionic fibers leave spinal nerves through white rami and enter paravertebral ganglia </li></ul><ul><li>paraverterbral ganglia and fibers that connect them make up the sympathetic trunk </li></ul>
  74. 74. Sympathetic Division <ul><li>postganglionic fibers extend from sympathetic ganglia to visceral organs </li></ul><ul><li>postganglionic fibers usually pass through gray rami and return to a spinal nerve before proceeding to an effector </li></ul><ul><li>Exception: preganglionic fibers to adrenal medulla do not synapse with postganglionic neurons </li></ul>
  75. 75. Sympathetic Division
  76. 76. Parasympathetic Division <ul><li>craniosacral division – location of preganglionic neurons </li></ul><ul><li>ganglia are near or within various organs </li></ul><ul><ul><li>terminal ganglia </li></ul></ul><ul><li>short postganglionic fibers </li></ul><ul><ul><li>continue to specific muscles or glands </li></ul></ul><ul><li>preganglionic fibers of the head are included in nerves III, VII, and IX </li></ul><ul><li>preganglionic fibers of thorax and abdomen are parts of nerve X </li></ul>
  77. 77. Parasympathetic Division
  78. 78. Autonomic Neurotransmitters <ul><li>Cholinergic Fibers </li></ul><ul><ul><li>release acetylcholine </li></ul></ul><ul><ul><li>preganglionic sympathetic and parasympathetic fibers </li></ul></ul><ul><ul><li>postganglionic parasympathetic fibers </li></ul></ul><ul><li>Adrenergic Fibers </li></ul><ul><ul><li>release norepinephrine </li></ul></ul><ul><ul><li>most postganglionic sympathetic fibers </li></ul></ul>
  79. 79. Actions of Autonomic Neurotransmitters <ul><li>depend on receptors in the membrane </li></ul><ul><li>Cholinergic receptors </li></ul><ul><ul><li>bind to acetlycholine </li></ul></ul><ul><ul><li>muscarinic </li></ul></ul><ul><ul><ul><li>excitatory </li></ul></ul></ul><ul><ul><ul><li>slow </li></ul></ul></ul><ul><ul><li>nicotinic </li></ul></ul><ul><ul><ul><li>excitatory </li></ul></ul></ul><ul><ul><ul><li>rapid </li></ul></ul></ul><ul><li>Adrenergic Receptors </li></ul><ul><ul><li>bind to epinephrine and norepinephrine </li></ul></ul><ul><ul><li>alpha and beta </li></ul></ul><ul><ul><ul><li>both elicit different responses on various effectors </li></ul></ul></ul>
  80. 80. Insert figure 11.39 Actions of Autonomic Neurotransmitters
  81. 81. Control of Autonomic Activity <ul><li>Controlled largely by CNS </li></ul><ul><li>Medulla oblongata regulates cardiac, vasomotor and respiratory activities </li></ul><ul><li>Hypothalamus regulates visceral functions, such as body temperature, hunger, thirst, and water and electrolyte balance </li></ul><ul><li>Limbic system and cerebral cortex control emotional responses </li></ul>
  82. 82. Life-Span Changes <ul><li>Brain cells begin to die before birth </li></ul><ul><li>Over average lifetime, brain shrinks 10% </li></ul><ul><li>Most cell death occurs in temporal lobes </li></ul><ul><li>By age 90, frontal cortex has lost half its neurons </li></ul><ul><li>Number of dendritic branches decreases </li></ul><ul><li>Decreased levels of neurotransmitters </li></ul><ul><li>Fading memory </li></ul><ul><li>Slowed responses and reflexes </li></ul><ul><li>Increased risk of falling </li></ul><ul><li>Changes in sleep patterns that result in fewer sleeping hours </li></ul>
  83. 83. Clinical Application Cerebral Injuries and Abnormalities <ul><li>Concussion </li></ul><ul><ul><li>brain jarred against cranium </li></ul></ul><ul><ul><li>loss of consciousness </li></ul></ul><ul><ul><li>temporary loss of memory </li></ul></ul><ul><ul><li>mental cloudiness </li></ul></ul><ul><ul><li>headache </li></ul></ul><ul><ul><li>recovery usually complete </li></ul></ul><ul><li>Cerebral Palsy </li></ul><ul><ul><li>motor impairment at birth </li></ul></ul><ul><ul><li>caused by blocked cerebral blood vessels during development </li></ul></ul><ul><ul><li>seizures </li></ul></ul><ul><ul><li>learning disabilities </li></ul></ul><ul><li>Cerebrovascular Accident </li></ul><ul><ul><li>stroke </li></ul></ul><ul><ul><li>sudden interruption in blood flow </li></ul></ul><ul><ul><li>brain tissues die </li></ul></ul>