Chapter 11   Nervous System II- Divisions of the Nervous System
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Chapter 11 Nervous System II- Divisions of the Nervous System

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Hole's Anatomy and Physiology

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Chapter 11   Nervous System II- Divisions of the Nervous System Chapter 11 Nervous System II- Divisions of the Nervous System Presentation Transcript

  • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 11 Lecture PowerPoint
  • 2401 Anatomy and Physiology I Chapter 11 Susan Gossett [email_address] Department of Biology Paris Junior College
  • Hole’s Human Anatomy and Physiology Twelfth Edition Shier  Butler  Lewis Chapter 11 Nervous System II: Divisions of the Nervous System Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • 11.1: Introduction
    • The central nervous system (CNS) consists of the brain and spinal cord.
    • The brainstem connects the brain to the spinal cord.
    • Communication to the peripheral nervous system (PNS) is by way of the spinal cord.
  • 11.2: Meninges
    • The meninges
      • Membranes of CNS
      • Protect the CNS
      • Three (3) layers:
        • Dura mater
          • “ Tough mother”
          • Venous sinuses
          • Falx
        • Arachnoid mater
          • “ Spiderweb-like”
          • Space contains cerebrospinal fluid (CSF)
        • Pia mater
          • “ Faithful mother”
          • Encapsulates blood vessels
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Scalp Cranium Cerebrum Cerebellum Spinal cord Meninges Meninges Cerebrum (b) (a) Gray matter White matter Subarachnoid space Falx cerebri Pia mater Dura mater Bone of skull Subcutaneous tissue Skin Tentorium cerebelli Vertebra Dural sinus Arachnoid granulation Arachnoid mater
  • Meninges of the Spinal Cord Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spinal cord Spinal cord Pia mater Arachnoid mater Dura mater Dorsal root Dorsal root Spinal nerve Epidural space (a) (b) Ventral root Dorsal root ganglion Thoracic vertebra Spinal nerve Dorsal root ganglion Subarachnoid space Dorsal branch (dorsal ramus) Ventral branch (ventral ramus) Ventral root Epidural space Body of vertebra
  • 11.3: Ventricles and Cerebrospinal Fluid
    • There are four (4) ventricles
    • The ventricles are interconnected cavities within cerebral hemispheres and brain stem
    • The ventricles are continuous with the central canal of the spinal cord
    • They are filled with cerebrospinal fluid (CSF)
    • The four (4) ventricles are:
      • Lateral ventricles (2)
        • Known as the first and second ventricles
      • Third ventricle
      • Fourth ventricle
    • Interventricular foramen
    • Cerebral aqueduct
    Lateral ventricle Third ventricle Fourth ventricle (a) Interventricular foramen Cerebral aqueduct To central canal of spinal cord Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Third ventricle (b) Cerebral aqueduct To central canal of spinal cord Fourth ventricle Lateral ventricle Interventricular foramen
  • Cerebrospinal Fluid
    • Secreted by the choroid plexus
    • Circulates in ventricles, central canal of spinal cord, and the subarachnoid space
    • Completely surrounds the brain and spinal cord
    • Excess or wasted CSF is absorbed by the arachnoid villi
    • Clear fluid similar to blood plasma
    • Volume is only about 120 ml.
    • Nutritive and protective
    • Helps maintain stable ion concentrations in the CNS
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Third ventricle Fourth ventricle Cerebral aqueduct Subarachnoid space Arachnoid mater Dura mater Pia mater Pia mater Central canal of spinal cord Subarachnoid space Filum terminale Arachnoid mater Dura mater Arachnoid granulations Choroid plexuses of third ventricle Blood-filled dural sinus Choroid plexus of fourth ventricle
  • 11.1 Clinical Application Cerebrospinal Fluid Pressure
  • 11.4: Spinal Cord
    • Slender column of nervous tissue continuous with brain and brainstem
    • Extends downward through vertebral canal
    • Begins at the foramen magnum and terminates at the first and second lumbar vertebrae (L1/L2) interspace
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Brainstem Spinal cord (a) (b) Foramen magnum Cervical enlargement Vertebral canal Lumbar enlargement Conus medullaris Cauda equina Filum terminale Conus medullaris Lumbar enlargement Cervical enlargement
  • Structure of the Spinal Cord Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. White matter Gray matter Lateral funiculus Posterior funiculus Gray commissure Central canal (a) Posterior horn Dorsal root of spinal nerve Dorsal root ganglion Ventral root of spinal nerve Anterior horn Anterior median fissure Portion of spinal nerve Anterior funiculus Posterior median sulcus
  • Functions of Spinal Cord
    • Center for spinal reflexes
    • Conduit (pathway) for nerve impulses to and from the brain and brainstem
  • Reflex Arcs
    • Reflexes are automatic, subconscious responses to stimuli within or outside the body
      • Simple reflex arc (sensory – motor)
      • Most common reflex arc (sensory – association – motor)
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Receptor (a) Sensory or afferent neuron Motor or efferent neuron Central Nervous System Effector (muscle or gland)
  • Reflex Arcs
  • General Components of a Spinal Reflex Receptor Sensory neuron Motor neuron White matter Gray matter Spinal cord Dorsal Interneuron 4 5 3 2 1 (b) Cell body of sensory neuron Effector (muscle or gland) Central canal Ventral I m p u l s e Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • Reflex Behavior
    • Example is the knee-jerk reflex
    • Simple monosynaptic reflex
    • Helps maintain an upright posture
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spinal cord Patella Patellar ligament Direction of impulse Axon of sensory neuron Cell body of sensory neuron Cell body of motor neuron Axon of motor neuron Effector (quadriceps femoris muscle group) Receptor associated with dendrites of sensory neuron
  • Reflex Behavior
    • Example is a withdrawal reflex (flexor reflex)
    • Prevents or limits tissue damage
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Interneuron Spinal cord Axon of sensory neuron Cell body of sensory neuron Dendrite of sensory neuron Pain receptor in skin Direction of impulse Cell body of motor neuron Axon of motor neuron Effector (flexor muscle contracts and withdraws part being stimulated) Tack
  • Reflex Arc
    • Example crossed extensor reflex
    • Crossing of sensory impulses within the reflex center to produce an opposite effect
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. = Stimulation = Inhibition Interneuron Flexor contracts Sensory neuron + + + – – – Motor neurons Extensor contracts Flexor relaxes Motor neurons Extensor relaxes
  • 11.2 Clinical Application Uses of Reflexes
  • Tracts of the Spinal Cord
    • Ascending tracts conduct sensory impulses to the brain
    • Descending tracts conduct motor impulses from the brain to motor neurons reaching muscles and glands
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Posterior spinocerebellar tract Lateral corticospinal tract Lateral reticulospinal tract Rubrospinal tract Anterior spinocerebellar tract Lateral spinothalamic tract Anterior reticulospinal tract Medial reticulospinal tract Fasciculus cuneatus Fasciculus gracilis Dorsal column Anterior spinothalamic tract Anterolateral system Anterior corticospinal tract
  • Ascending Tracts
    • Major ascending (sensory) spinal cord tracts:
      • Fasciculus gracilis and fasciculus cuneatus
      • Spinothalamic tracts
        • Lateral and anterior
      • Spinocerebellar tracts
        • Posterior and anterior
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Midbrain Pons Medulla Thalamus Sensory cortex of cerebrum Cerebrum (frontal section) Brainstem (transverse sections) Spinal cord (transverse section) Sensory fibers cross over Spinothalamic tract Fasciculus Cuneatus tract Sensory impulse from skin temperature or pain receptors
  • Descending Tracts
    • Major descending (motor) spinal cord tracts:
      • Corticospinal tracts
        • Lateral and anterior
      • Reticulospinal tracts
        • Lateral, anterior and medial
      • Rubrospinal tract
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Midbrain Pons Brainstem (transverse sections) Spinal cord (transverse section) Motor cortex of cerebrum Cerebrum (frontal section) Corticospinal tract Medulla oblongata Motor fibers cross over Motor impulse to Skeletal muscle
  • Nerve Tracts of the Spinal Cord
  • 11.3 Clinical Application Spinal Cord Injuries
  • 11.5: Brain
    • Functions of the brain:
      • Interprets sensations
      • Determines perception
      • Stores memory
      • Reasoning
      • Makes decisions
      • Coordinates muscular movements
      • Regulates visceral activities
      • Determines personality
    • Major parts of the brain:
      • Cerebrum
        • Frontal lobes
        • Parietal lobes
        • Occipital lobes
        • Temporal lobes
        • Insula
      • Diencephalon
      • Cerebellum
      • Brainstem
        • Midbrain
        • Pons
        • Medulla oblongata
  • The Brain Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cerebrum Diencephalon Midbrain Pons Medulla oblongata Spinal cord Cerebellum Fornix (b) Skull Meninges Cerebrum Diencephalon Brainstem (a) Sulcus Gyrus Fornix Cerebellum Spinal cord Midbrain Pons Medulla oblongata Corpus callosum Corpus callosum Transverse fissure © Martin M. Rotker/Photo Researchers, Inc.
  • Brain Development
    • Neural tube
    • Three primary vesicles:
      • Forebrain
      • (Prosencephalon)
      • Midbrain
      • (Mesencephalon)
      • Hindbrain
      • (Rhombencephalon)
    • Five secondary vesicles:
      • Telencephalon
      • Diencephalon
      • Mesencephalon
      • Metencephalon
      • Myelencephalon
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Prosencephalon (forebrain) Mesencephalon (midbrain) Rhombencephalon (hindbrain) Neural tube (a) Diencephalon Mesencephalon Myelencephalon Metencephalon Neural tube (b) Telencephalon (c) Diencephalon Midbrain Pons and Cerebellum Spinal cord Cerebral hemispheres Medulla oblongata
  • Brain Development
  • Structure of the Cerebrum
    • Corpus callosum
      • Connects cerebral hemispheres (a commissure)
    • Gyri
      • Bumps or convolutions
    • Sulci
      • Grooves in gray matter
        • Central sulcus
    • Fissures
      • Longitudinal: separates the cerebral hemispheres
      • Transverse: separates cerebrum from cerebellum
      • Lateral fissure of Sylvius
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Central sulcus Gyrus Sulcus Frontal lobe Lateral sulcus Parietal lobe Occipital lobe Central sulcus Parietal lobe Occipital lobe (a) (b) (c) Parietal lobe Central sulcus Occipital lobe Frontal lobe Insula Temporal lobe Longitudinal fissure Transverse fissure Cerebellar hemisphere Retracted temporal lobe
  • Lobes of the Cerebrum
    • Five (5) lobes bilaterally:
      • Frontal lobe
      • Parietal lobe
      • Temporal lobe
      • Occipital lobe
      • Insula aka ‘Island of Reil’
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (c) Parietal lobe Central sulcus Occipital lobe Frontal lobe Insula Retracted temporal lobe
  • Functions of the Cerebrum
    • Interpreting impulses
    • Initiating voluntary movements
    • Storing information as memory
    • Retrieving stored information
    • Reasoning
    • Seat of intelligence and personality
  • Functional Regions of the Cerebral Cortex
    • Cerebral cortex
      • Thin layer of gray matter that constitutes the outermost portion of cerebrum
      • Contains 75% of all neurons in the nervous system
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Frontal eye field Central sulcus Parietal lobe Occipital lobe Cerebellum Brainstem Interpretation of auditory patterns Lateral sulcus Auditory area Sensory areas involved with cutaneous and other senses Sensory speech area ( Wernicke’s area) Combining visual images, visual recognition of objects Visual area Temporal lobe Motor speech area (Broca’s area) Motor areas involved with the control of voluntary muscles Concentration, planning, problem solving Front lobe
  • Functions of the Cerebral Lobes
  • Sensory Areas (post-central sulcus)
    • Cutaneous sensory area
      • Parietal lobe
      • Interprets sensations on skin
    • Visual area
      • Occipital lobe
      • Interprets vision
    • Auditory area
      • Temporal lobe
      • Interprets hearing
    • Sensory area for taste
      • Near base of the central sulcus
    • Sensory area for smell
      • Arises from centers deep within the cerebrum
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Frontal eye field Central sulcus Parietal lobe Occipital lobe Cerebellum Brainstem Interpretation of auditory patterns Lateral sulcus Auditory area Sensory areas involved with cutaneous and other senses Sensory speech area ( Wernicke’s area) Combining visual images, visual recognition of objects Visual area Temporal lobe Motor speech area (Broca’s area) Motor areas involved with the control of voluntary muscles Concentration, planning, problem solving Front lobe
  • Sensory Areas Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Parietal lobe Sensory area Central sulcus Motor area Frontal lobe Swallowing Forearm Arm Pelvis Thigh Leg Lips Forearm Arm Neck Pelvis Thigh Leg Genitals (a) Motor area (b) Sensory area Longitudinal fissure Salivation Vocalization Mastication Facial expression Thumb, fingers, and hand Trunk Foot and toes Tongue and pharynx Teeth and gums Upper face Hand, fingers, and thumb Trunk Foot and toes Longitudinal fissure
  • Association Areas
    • Regions that are not primary motor or primary sensory areas
    • Widespread throughout the cerebral cortex
    • Analyze and interpret sensory experiences
    • Provide memory, reasoning, verbalization, judgment, emotions
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Frontal eye field Central sulcus Parietal lobe Occipital lobe Cerebellum Brainstem Interpretation of auditory patterns Lateral sulcus Auditory area Sensory areas involved with cutaneous and other senses Sensory speech area ( Wernicke’s area) Combining visual images, visual recognition of objects Visual area Temporal lobe Motor speech area (Broca’s area) Motor areas involved with the control of voluntary muscles Concentration, planning, problem solving Front lobe
  • Association Areas
    • Frontal lobe association areas
      • Concentrating
      • Planning
      • Complex problem solving
    • Parietal lobe association areas
      • Understanding speech
      • Choosing words to express thought
    • Temporal lobe association areas
      • Interpret complex sensory experiences
      • Store memories of visual scenes, music, and complex patterns
    • Occipital lobe association areas
      • Analyze and combine visual images with other sensory experiences
  • Motor Areas (pre-central sulcus) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Frontal eye field Central sulcus Parietal lobe Occipital lobe Cerebellum Brainstem Interpretation of auditory patterns Lateral sulcus Auditory area Sensory areas involved with cutaneous and other senses Sensory speech area ( Wernicke’s area) Combining visual images, visual recognition of objects Visual area Temporal lobe Motor speech area (Broca’s area) Motor areas involved with the control of voluntary muscles Concentration, planning, problem solving Front lobe
    • Primary motor areas
      • Frontal lobes
      • Control voluntary muscles
    • Broca’s area
      • Anterior to primary motor cortex
      • Usually in left hemisphere
      • Controls muscles needed for speech
    • Frontal eye field
      • Above Broca’s area
      • Controls voluntary movements of eyes and eyelids
  • Motor Areas Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Parietal lobe Sensory area Central sulcus Motor area Frontal lobe Swallowing Forearm Arm Pelvis Thigh Leg Lips Forearm Arm Neck Pelvis Thigh Leg Genitals (a) Motor area (b) Sensory area Longitudinal fissure Salivation Vocalization Mastication Facial expression Thumb, fingers, and hand Trunk Foot and toes Tongue and pharynx Teeth and gums Upper face Hand, fingers, and thumb Trunk Foot and toes Longitudinal fissure
  • Hemisphere Dominance
    • The left hemisphere is dominant in most individuals
    • Dominant hemisphere controls:
      • Speech
      • Writing
      • Reading
      • Verbal skills
      • Analytical skills
      • Computational skills
    • Nondominant hemisphere controls:
      • Nonverbal tasks
      • Motor tasks
      • Understanding and interpreting musical and visual patterns
      • Provides emotional and intuitive thought processes
  • Memory
    • Short term memory
      • Working memory
      • Closed neuronal circuit
      • Circuit is stimulated over and over
      • When impulse flow ceases, memory does also unless it enters long-term memory via memory consolidation
    • Long term memory
      • Changes structure or function of neurons
      • Enhances synaptic transmission
  • 11.4 Clinical Application Traumatic Brain Injury
  • Basal Nuclei
    • Masses of gray matter
    • Deep within cerebral hemispheres
    • Caudate nucleus, putamen, and globus pallidus
    • Produce dopamine
    • Control certain muscular activities
      • Primarily by inhibiting motor functions
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Thalamus Hypothalamus Brainstem Putamen Cerebellum Spinal cord Longitudinal fissure Right cerebral hemisphere Caudate nucleus Globus pallidus Basal nuclei
  • Diencephalon
    • Between cerebral hemispheres and above the brainstem
    • Surrounds the third ventricle
    • Thalamus
    • Epithalamus
    • Hypothalamus
    • Optic tracts
    • Optic chiasm
    • Infundibulum
    • Posterior pituitary
    • Mammillary bodies
    • Pineal gland
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pyramidal tract Pons Optic nerve Optic chiasma Thalamus Spinal cord Pituitary gland Pineal gland Optic tract Mammillary body (a) (b) Olive Corpora quadrigemina Cerebral peduncles Superior colliculus Inferior colliculus Third ventricle Fourth ventricle Cerebellar peduncles Medulla oblongata
  • Diencephalon
    • Thalamus
      • Gateway for sensory impulses heading to cerebral cortex
      • Receives all sensory impulses (except smell)
      • Channels impulses to appropriate part of cerebral cortex for interpretation
    • Hypothalamus
      • Maintains homeostasis by regulating visceral activities
      • Links nervous and endocrine systems (hence some say the neuroendocrine system
  • Diencephalon
    • Consists of:
      • Portions of frontal lobe
      • Portions of temporal lobe
      • Hypothalamus
      • Thalamus
      • Basal nuclei
      • Other deep nuclei
    • Functions:
      • Controls emotions
      • Produces feelings
      • Interprets sensory impulses
    The Limbic System
  • 11.5 Clinical Application Parkinson Disease
  • Brainstem
    • Three parts:
    • Midbrain
    • Pons
    • Medulla Oblongata
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spinal cord Thalamus Hypothalamus Diencephalon Pons Midbrain Corpus callosum Corpora quadrigemina Cerebral aqueduct Reticular formation Medulla oblongata
  • Midbrain Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pyramidal tract Pons Optic nerve Optic chiasma Thalamus Spinal cord Pituitary gland Pineal gland Optic tract Mammillary body (a) (b) Olive Corpora quadrigemina Cerebral peduncles Superior colliculus Inferior colliculus Third ventricle Fourth ventricle Cerebellar peduncles Medulla oblongata
    • Between diencephalon and pons
    • Contains bundles of fibers that join lower parts of brainstem and spinal cord with higher part of brain
    • Cerebral aqueduct
    • Cerebral peduncles (bundles of nerve fibers)
    • Corpora quadrigemina (centers for visual and auditory reflexes)
  • Pons Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pyramidal tract Pons Optic nerve Optic chiasma Thalamus Spinal cord Pituitary gland Pineal gland Optic tract Mammillary body (a) (b) Olive Corpora quadrigemina Cerebral peduncles Superior colliculus Inferior colliculus Third ventricle Fourth ventricle Cerebellar peduncles Medulla oblongata
    • Rounded bulge on underside of brainstem
    • Between medulla oblongata and midbrain
    • Helps regulate rate and
    • depth of breathing
    • Relays nerve impulses to and from medulla oblongata and cerebellum
  • Medulla Oblongata Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pyramidal tract Pons Optic nerve Optic chiasma Thalamus Spinal cord Pituitary gland Pineal gland Optic tract Mammillary body (a) (b) Olive Corpora quadrigemina Cerebral peduncles Superior colliculus Inferior colliculus Third ventricle Fourth ventricle Cerebellar peduncles Medulla oblongata
    • Enlarged continuation of spinal cord
    • Conducts ascending and descending impulses between brain and spinal cord
    • Contains cardiac, vasomotor, and respiratory control centers
    • Contains various nonvital reflex control centers (coughing, sneezing, swallowing, and vomiting)
  • Reticular Formation
    • Complex network of nerve fibers scattered throughout the brain stem
    • Extends into the diencephalon
    • Connects to centers of hypothalamus, basal nuclei, cerebellum, and cerebrum
    • Filters incoming sensory information
    • Arouses cerebral cortex into state of wakefulness
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spinal cord Thalamus Hypothalamus Diencephalon Pons Midbrain Corpus callosum Corpora quadrigemina Cerebral aqueduct Reticular formation Medulla oblongata
  • Types of Sleep
    • Slow wave
      • Non-REM sleep
      • Person is tired
      • Decreasing activity of reticular system
      • Restful
      • Dreamless
      • Reduced blood pressure and respiratory rate
      • Ranges from light to heavy
      • Alternates with REM sleep
    • Rapid Eye Movement (REM)
      • Paradoxical sleep
      • Some areas of brain active
      • Heart and respiratory rates irregular
      • Dreaming occurs
  • Cerebellum
    • Inferior to occipital lobes
    • Posterior to pons and medulla oblongata
    • Two hemispheres
    • Vermis connects hemispheres
    • Cerebellar cortex (gray matter)
    • Arbor vitae (white matter)
    • Cerebellar peduncles (nerve fiber tracts)
    • Dentate nucleus (largest nucleus in cerebellum)
    • Integrates sensory information concerning position of body parts
    • Coordinates skeletal muscle activity
    • Maintains posture
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Thalamus Superior peduncle Middle peduncle Inferior peduncle Pons Medulla oblongata Cerebellum Corpus callosum Longitudinal fissure
  • Major Parts of the Brain
  • 11.6 Clinical Application Brain Waves
  • 11.6: Peripheral Nervous System
    • Cranial nerves arising from the brain
      • Somatic fibers connecting to the skin and skeletal muscles
      • Autonomic fibers connecting to viscera
    • Spinal nerves arising from the spinal cord
      • Somatic fibers connecting to the skin and skeletal muscles
      • Autonomic fibers connecting to viscera
  • Nervous System Subdivisions
  • Structure of a Peripheral Nerve Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Peripheral nerve Epineurium Axon Neurilemma Myelin sheath Schwann cell Node of Ranvier Endoneurium Perineurium Fascicle Sensory receptor Motor neuron ending
  • Nerve and Nerve Fiber Classification
    • Sensory nerves
      • Conduct impulses into brain or spinal cord
    • Motor nerves
      • Conduct impulses to muscles or glands
    • Mixed (both sensory and motor) nerves
      • Contain both sensory nerve fibers and motor nerve fibers
      • Most nerves are mixed nerves
      • ALL spinal nerves are mixed nerves (except the first pair)
  • Nerve Fiber Classification
    • General somatic efferent (GSE) fibers
      • Carry motor impulses from CNS to skeletal muscles
    • General visceral efferent (GVE) fibers
      • Carry motor impulses away from CNS to smooth muscles and glands
    • General somatic afferent (GSA) fibers
      • Carry sensory impulses to CNS from skin and skeletal muscles
    • General visceral afferent (GVA) fibers
      • Carry sensory impulses to CNS from blood vessels and internal organs
  • Nerve Fiber Classification
    • Special somatic efferent (SSE) fibers
      • Carry motor impulses from brain to muscles used in chewing, swallowing, speaking and forming facial expressions
    • Special visceral afferent (SVA) fibers
      • Carry sensory impulses to brain from olfactory and taste receptors
    • Special somatic afferent (SSA) fibers
      • Carry sensory impulses to brain from receptors of sight, hearing and equilibrium
  • Cranial Nerves Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Olfactory bulb Hypoglossal (XII) Optic tract Olfactory tract Olfactory (I) Optic (II) Oculomotor (III) Abducens (VI) Facial (VII) Glossopharyngeal (IX) Accessory (XI) Trochlear (IV) Trigeminal (V) Vestibulocochlear (VIII) Vagus (X)
  • Cranial Nerves
    • Remember:
      • Cranial nerves are designated ‘ CN ’
      • Cranial nerves are designated with Roman numerals (I – XII)
  • Cranial Nerves I and II
    • Olfactory nerve (CN I)
      • Sensory nerve
      • Fibers transmit impulses associated with smell
    • Optic nerve (CN II)
      • Sensory nerve
      • Fibers transmit impulses associated with vision
  • Cranial Nerves III and IV
    • Trochlear nerve (CN IV)
      • Primarily motor nerve
      • Motor impulses to muscles that move the eyes
      • Some sensory
        • Proprioceptors
    • Oculomotor nerve (CN III)
      • Primarily motor nerve
      • Motor impulses to muscles that:
        • Raise eyelids
        • Move the eyes
        • Focus lens
        • Adjust light entering eye
      • Some sensory
        • Proprioceptors
  • Cranial Nerve V
    • Trigeminal nerve (CN V)
      • Mixed nerve
      • “ Three (3) sisters”
      • (1) Ophthalmic division
        • Sensory from surface of eyes, tear glands, scalp, forehead, and upper eyelids
      • (2) Maxillary division
        • Sensory from upper teeth, upper gum, upper lip, palate, and skin of face
      • (3) Mandibular division
        • Sensory from scalp, skin of jaw, lower teeth, lower gum, and lower lip
        • Motor to muscles of mastication and muscles in floor of mouth
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lacrimal nerve Eye Maxilla Mandible Lacrimal gland Infraorbital nerve Tongue Mental nerve Ophthalmic division Maxillary division Mandibular division Lingual nerve Inferior alveolar nerve
  • Cranial Nerves VI and VII
    • Abducens nerve (CN VI)
      • Primarily motor nerve
      • Motor impulses to muscles that move the eyes
      • Some sensory
        • Proprioceptors
    • Facial nerve (CN VII)
      • Mixed nerve
      • Sensory from taste receptors
      • Motor to muscles of facial expression, tear glands, and salivary glands
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Zygomatic nerve Buccal nerve Facial nerve Mandibular nerve Cervical nerve Temporal nerve Posterior auricular nerve Parotid salivary gland 68
  • Cranial Nerves VIII and IX
    • Vestibulocochlear nerve (CN VIII)
      • A.k.a acoustic or auditory nerve
      • Sensory nerve
      • Two (2) branches:
        • Vestibular branch
          • Sensory from equilibrium receptors of ear
        • Cochlear branch
          • Sensory from hearing receptors
    • Glossopharyngeal nerve (CN IX)
      • Mixed nerve
      • Sensory from pharynx, tonsils, tongue and carotid arteries
      • Motor to salivary glands and muscles of pharynx
  • Cranial Nerve X
    • Vagus nerve (CN X)
      • Mixed nerve
      • Somatic motor to muscles of speech and swallowing
      • Autonomic motor to viscera of thorax and abdomen
      • Sensory from pharynx, larynx, esophagus, and viscera of thorax and abdomen
    Meningeal branch Auricular branch Pharyngeal branch Palate Cardiac nerves Heart Liver Kidney Nerve XI Nerve XII Carotid body Large intestine Lung Stomach Spleen Pancreas Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior laryngeal nerve Recurrent laryngeal nerve Superior ganglion of vagus nerve Inferior ganglion of vagus nerve Left vagus nerve Small intestine
  • Cranial Nerves XI and XII
    • Accessory nerve (CN XI)
      • Primarily motor nerve
      • We called this “Spinal” Accessory because:
        • Cranial branch
          • Motor to muscles of soft palate, pharynx and larynx
        • Spinal branch
          • Motor to muscles of neck and back
          • Some sensory
            • Proprioceptor
    • Hypoglossal nerve (CN XII)
      • Primarily motor
      • Motor to muscles of the tongue
      • Some sensory
        • Proprioceptor
  • Functions of Cranial Nerves
  • Spinal Nerves
    • ALL are mixed nerves (except the first pair)
    • 31 pairs of spinal nerves:
      • 8 cervical nerves
        • (C1 to C8)
      • 12 thoracic nerves
        • (T1 to T12)
      • 5 lumbar nerves
        • (L1 to L5)
      • 5 sacral nerves
        • (S1 to S5)
      • 1 coccygeal nerve
        • (Co or Cc)
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cauda equina C1 C2 C3 C4 C5 C6 C7 C8 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 L1 L2 L3 L4 L5 S2 S3 S4 S1 S5 Co Posterior view Cervical nerves Thoracic nerves Lumbar nerves Sacral nerves Coccygeal nerve
  • Spinal Nerves
    • Dorsal root (aka posterior root )
      • Sensory root
      • Axons of sensory neurons are in the dorsal root ganglion
    • Dorsal root ganglion
      • Aka DRG
      • Cell bodies of sensory neurons whose axons conduct impulses inward from peripheral body parts
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lateral horn Ventral root (a) (b) Dorsal root Dorsal root Spinal nerve Dorsal root ganglion Posterior median sulcus Posterior horn Anterior horn Central canal Anterior median fissure Dorsal branch of spinal nerve Ventral branch of spinal nerve Visceral branch of spinal nerve Paravertebral ganglion Ventral branch of spinal nerve (ventral ramus) Dorsal branch of spinal nerve (dorsal ramus) Paravertebral ganglion Visceral branch of spinal nerve Ventral root
  • Dermatome
    • An area of skin that the sensory nerve fibers of a particular spinal nerve innervate
    C2 C3 C4 C5 C6 T1 C6 C7 S2 S3 C8 L1 L2 L3 L4 L5 T12 T1 S1 (a) (b) S5 C0 S4 S3 S2 S1 L5 L4 L3 L2 L1 L5 L1 C8 T1 T12 C7 C6 C5 C4 C3 C2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • Spinal Nerves Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lateral horn Ventral root (a) (b) Dorsal root Dorsal root Spinal nerve Dorsal root ganglion Posterior median sulcus Posterior horn Anterior horn Central canal Anterior median fissure Dorsal branch of spinal nerve Ventral branch of spinal nerve Visceral branch of spinal nerve Paravertebral ganglion Ventral branch of spinal nerve (ventral ramus) Dorsal branch of spinal nerve (dorsal ramus) Paravertebral ganglion Visceral branch of spinal nerve Ventral root
    • Ventral root (aka anterior root )
      • Motor root
      • Axons of motor neurons whose cell bodies are in the spinal cord
    • Spinal nerve
      • Union of ventral root and dorsal roots
      • Hence we now have a “mixed” nerve
  • Nerve Plexuses
    • Nerve plexus
      • Complex networks formed by anterior branches of spinal nerves
      • The fibers of various spinal nerves are sorted and recombined
      • There are three (3) nerve plexuses:
    • (1) Cervical plexus
      • Formed by anterior branches of C1-C4 spinal nerves
      • Lies deep in the neck
      • Supply to muscles and skin of the neck
      • C3-C4-C5 nerve roots contribute to phrenic nerves bilaterally
  • Brachial Plexus
    • (2) Brachial plexus
      • Formed by anterior branches C5-T1
      • Lies deep within shoulders
      • There are five (5) branches:
      • 1. Musculocutaneous nerve
        • Supply muscles of anterior arms and skin of forearms
      • 2. Ulnar and 3. Median nerves
        • Supply muscles of forearms and hands
        • Supply skin of hands
      • 4. Radial nerve
        • Supply posterior muscles of arms and skin of forearms and hands
      • 5. Axillary nerve
        • Supply muscles and skin of anterior, lateral, and posterior arms
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Musculo- cutaneous n. Musculocutaneous n. Humerus Thoracodorsal n. Lower subscapular n. Suprascapular n. Lateral pectoral n. Medial pectoral n. Axillary n. Axillary n. Radial n. Radial n. Radius Ulna Ulnar n. Ulnar n. Median n. Median n. C5 C5 C6 C6 C7 C7 C8 C8 T1 T1 (a) (b) Ventral rami: C5, C6, C7, C8, T1 Anterior divisions Posterior divisions Trunks: upper, middle, lower Dorsal scapular n.
  • Lumbosacral Plexus
    • (3) Lumbosacral plexus
      • Formed by the anterior branches of L1-S5 roots
      • Can be a lumbar (L1-L5) plexus and a sacral (S1-S5) plexus
      • Extends from lumbar region into pelvic cavity
      • Obturator nerve
        • Supply motor impulses to adductors of thighs
      • Femoral nerve
        • Supply motor impulses to muscles of anterior thigh and sensory impulses from skin of thighs and legs
      • Sciatic nerve
        • Supply muscles and skin of thighs, legs and feet
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sciatic n. Saphenous n. Femoral n. Obturator n. Tibial n. Pudendal n. (b) (c) (a) Femoral n. Obturator n. Pudendal n. Sciatic n. L1 L2 L3 L4 L5 S1 S2 S3 S4 S5 Ventral rami Anterior divisions Posterior divisions Lateral femoral cutaneous n. Superior gluteal n. Inferior gluteal n. Superior gluteal n. Inferior gluteal n. Sacral plexus Common fibular (peroneal) n. Posterior cutaneous n. Common fibular (peroneal) n. Tibial n.
  • Plexuses C1 C2 C3 C4 C5 C6 C7 C8 T1 T2 T3 T4 T5 T6 T8 T9 T10 T11 T12 L1 L2 L3 L4 L5 S2 S3 S4 S5 Co Posterior view Cervical plexus (C1–C4) Lumbosacral plexus (T12–S5) Sciatic nerve Brachial plexus (C5–T1) Obturator nerve Phrenic nerve Ulnar nerve Median nerve Radial nerve Axillary nerve T7 S1 Cauda equina Musculocutaneous nerve Femoral nerve Intercostal nerves Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • 11.7 Clinical Application Spinal Nerve Injuries
  • 11.7: Autonomic Nervous System
    • Functions without conscious effort
    • Controls visceral activities
    • Regulates smooth muscle, cardiac muscle, and glands
    • Efferent fibers typically lead to ganglia outside of the CNS
    • Two autonomic divisions regulate:
      • Sympathetic division (speeds up)
        • Prepares body for ‘fight or flight’ situations
      • Parasympathetic division (slows down)
        • Prepares body for ‘resting and digesting’ activities
  • Autonomic Nerve Fibers
    • All of the neurons are motor (efferent)
    • Preganglionic fibers
      • Axons of preganglionic neurons
      • Neuron cell bodies in CNS
    • Postganglionic fibers
      • Axons of postganglionic neurons
      • Neuron cell bodies in ganglia
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Interneurons Spinal cord Dorsal root ganglion Viscera (b) Somatic pathway Skin Somatic motor neuron Dorsal root ganglion Sensory neuron Autonomic ganglion Preganglionic fiber Postganglionic fiber Skeletal muscle Sensory neuron (a) Autonomic pathway
  • Sympathetic Division
    • Thoracolumbar division – location of preganglionic neurons
    • Preganglionic fibers leave spinal nerves through white rami and enter paravertebral ganglia
    • Paraverterbral ganglia and fibers that connect them make up the sympathetic trunk
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ventral root Spinal nerves Spinal cord Dorsal root Pia mater Sympathetic trunk Paravertebral sympathetic ganglion Transverse process Vertebral notch (forms part of intervertebral foramen) Body of vertebra Dura mater Arachnoid mater Dorsal root ganglion
  • Sympathetic Division
    • Postganglionic fibers extend from sympathetic ganglia to visceral organs
    • Postganglionic fibers usually pass through gray rami and return to a spinal nerve before proceeding to an effector
    • Exception: preganglionic fibers to adrenal medulla do not synapse with postganglionic neurons
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spinal cord Ventral root Dorsal root Sympathetic trunk Posterior horn Lateral horn Anterior horn Preganglionic neuron Postganglionic neuron Dorsal root ganglion Spinal nerve Visceral effector (intestine) Collateral ganglion To visceral effectors (smooth muscle of blood vessels, arrector pili muscles, and sweat glands) Gray ramus White ramus Dorsal branch of spinal nerve Ventral branch of spinal nerve Paravertebral sympathetic ganglion
  • Sympathetic Division Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lacrimal gland Skin Eye Blood vessels Heart Lungs Adrenal gland Kidney Uterus Penis Liver Stomach Gallbladder Pancreas Ovary Scrotum Small intestine Large intestine Trachea Parotid gland, submandibular and sublingual glands Urinary bladder Preganglionic neuron Postganglionic neuron Sympathetic chain ganglia Inferior mesenteric ganglion Spinal cord Superior mesenteric ganglion Celiac ganglion Fibers to skin, blood vessels, and adipose tissue Celiac and pulmonary plexuses
  • Parasympathetic Division
    • Craniosacral division – location of preganglionic neurons
    • Ganglia are near or within various organs
      • Terminal ganglia
    • Short postganglionic fibers
      • Continue to specific muscles or glands
    • Preganglionic fibers of the head are included in nerves III, VII, and IX
    • Preganglionic fibers of thorax and abdomen are parts of nerve X
  • Parasympathetic Division Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Heart Trachea Lung Gallbladder Liver Stomach Spleen Pancreas Small intestine Large intestine Kidney Uterus Scrotum Otic ganglion Ciliary ganglion Eye Penis Ovary Sphenopalatine ganglion Cranial nerve III Cranial Nerve VII Submandibular ganglion Cranial nerve IX Cranial nerve X (Vagus) Cardiac and pulmonary plexuses Celiac plexus Superior hypogastric plexus Inferior hypogastric plexus Spinal cord Pelvic nerves Urinary bladder Parotid gland Submandibular and sublingual glands Lacrimal gland Preganglionic neuron Postganglionic neuron
  • Autonomic Neurotransmitters
    • Cholinergic fibers
      • Release acetylcholine
      • Preganglionic sympathetic and parasympathetic fibers
      • Postganglionic parasympathetic fibers
    • Adrenergic fibers
      • Release norepinephrine
      • Most postganglionic sympathetic fibers
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Brain Postganglionic fiber (axon) Preganglionic fiber (axon) Ganglion Sympathetic neurons ACh = acetylcholine (cholinergic) NE = norepinephrine (adrenergic) ACh ACh ACh ACh ACh ACh NE NE Cranial parasympathetic neurons Sacral parasympathetic neurons Collateral ganglion Paravertebral ganglion Visceral effectors
  • Actions of Autonomic Neurotransmitters
    • Result from binding to protein receptors in the membrane of effector cells:
    • Cholinergic receptors
      • Bind to acetylcholine (Ach)
      • Muscarinic
        • Excitatory
        • Slow
      • Nicotinic
        • Excitatory
        • Rapid
    • Adrenergic receptors
      • Bind to epinephrine and norepinephrine
      • Alpha and beta
        • Both elicit different responses on various effectors
  • Terminating Autonomic Neurotransmitter Actions
    • The enzyme acetylcholinesterase rapidly decomposes the acetylcholine that cholinergic fibers release.
    • Norepinephrine from adrenergic fibers is removed by active transport.
  • Control of Autonomic Activity
    • Controlled largely by CNS
    • Medulla oblongata regulates cardiac, vasomotor and respiratory activities
    • Hypothalamus regulates visceral functions, such as body temperature, hunger, thirst, and water and electrolyte balance
    • Limbic system and cerebral cortex control emotional responses
  • 11.8: Lifespan Changes
    • Brain cells begin to die before birth
    • Over average lifetime, brain shrinks 10%
    • Most cell death occurs in temporal lobes
    • By age 90, frontal cortex has lost half its neurons
    • Number of dendritic branches decreases
    • Decreased levels of neurotransmitters
    • Fading memory
    • Slowed responses and reflexes
    • Increased risk of falling
    • Changes in sleep patterns that result in fewer sleeping hours
  • Important Points in Chapter 11: Outcomes to be Assessed
    • 11.1: Introduction
    • Describe the general structure of the brain.
    • Describe the relationship among the brain, brainstem, and spinal cord.
    • 11.2: Meninges
    • Describe the coverings of the brain and spinal cord.
    • 11.3: Ventricles and Cerebrospinal Fluid
    • Describe the formation and function of cerebrospinal fluid.
    • 11.4: Spinal Cord
    • Describe the structure of the spinal cord and its major functions.
    • Describe a reflex arc.
    • Describe reflex behavior.
    • 11.5: Brain
    • Name the major parts of the brain and describe the functions of each.
    • Distinguish among motor, sensory, association areas of the cerebral cortex.
  • Important Points in Chapter 11: Outcomes to be Assessed
    • Explain hemisphere dominance.
    • Explain stages in memory storage.
    • Explain the functions of the limbic system and reticular formation.
    • 11.6: Peripheral Nervous System
    • List the major parts of the peripheral nervous system.
    • Describe the structure of a peripheral nerve and how its fibers are classified.
    • Name the cranial nerves and list their major functions.
    • Explain how spinal nerves are named and their functions
    • 11.7: Autonomic Nervous System
    • Describe the general characteristics of the autonomic nervous system.
    • Distinguish between the sympathetic and the parasympathetic divisions of the autonomic nervous system.
    • Describe a sympathetic and a parasympathetic nerve pathway.
    • Explain how the autonomic neurotransmitters differently affect visceral effectors
  • Quiz 11 Complete Quiz 11 now! Read Chapter 12.