PowerPoint Lecture Outlines
to accompany
Hole’s Human
Anatomy and Physiology
Tenth Edition
Shier w Butler w Lewis
Chapter
11
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
11-1
Chapter 11
Nervous System II
Meninges
• membranes surrounding CNS
• protect CNS
• three layers
• dura mater – Hard mother, outer most layer
•Double layer with fluid and blood vessels
•Contains large veins – dural sinuses
• arachnoid mater – weblike
•Subarachnoid -CSF
• pia mater – inner, delicate mother
11-2
Meninges of the Spinal Cord
11-3
Ventricles
• interconnected cavities
• within cerebral hemispheres and brain stem
• continuous with central canal of spinal cord
• filled with cerebrospinal fluid (CSF)
• lateral ventricles
• third ventricle
• fourth ventricle
• cerebral aqueduct
11-4
Cerebrospinal Fluid
• secreted
by choroid plexus- within the lateral
ventricles, interventricular foramen, third ventricle,
cerebral aqueduct, and fourth ventricle. Then flows to
the central canal of spinal cord, and subarachnoid
space. CSF is reabsorbed by granulations that penetrate
the inner dura mater ( Dural Sinus).
• completely surrounds brain and spinal cord
• clear liquid
• nutritive and protective
• helps maintain stable ion concentrations in CNS
11-5
Spinal Cord Structure
• extends foramen magnum to 2nd lumbar vertebra
11-6
Cross Section of Spinal Cord
11-7
Spinal Cord Functions
• center for spinal reflexes
• conduit for nerve impulses to and
from the brain
11-8
Reflex Arcs
Reflexes – automatic, subconscious responses to stimuli
11-9
Knee-jerk Reflex
• helps maintain posture
11-10
Withdrawal Reflex
• protective
11-11
Crossed-Extensor Reflex
• flexor muscles contract
• flexor muscles on opposite side inhibited
• extensor muscles on opposite side contract for balance
11-12
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
11-13
Ascending Tracts
• fasciculus cuneatus
• lateral spinothalamic
11-14
Corticospinal Tract
11-15
Brain
Functions
• interprets sensations
• determines perception
• stores memory
• reasoning
• makes decisions
• coordinates muscular
movements
• regulates visceral activities
• determines personality
Major Parts
• cerebrum
• two cerebellar hemispheres
• diencephalon
• brain stem
• cerebellum
11-16
Brain Development
Three Major Vesicles
1. Forebrain
2. Midbrain
3. Hindbrain
Forebrain (prosencephalon)
• anterior portion (telencephalon)
• cerebrum
• basal ganglia
• posterior portion (diencephalon)
• thalamus
• hypothalamus
• posterior pituitary
• pineal gland
11-17
Brain Development
Midbrain
(mesencephalon)
• midbrain
Hindbrain
(rhombencephalon)
• anterior portion
(metencephalon)
• cerebellum
• pons
• posterior portion
(myelencephalon)
• medulla oblongata
11-18
Structure of Cerebrum
• corpus callosum
• connects hemispheres
• convolutions
• bumps or gyri
• sulci
• grooves
• longitudinal fissure
• separates hemispheres
• transverse fissure
• separates cerebrum
from cerebellum
11-19
Lobes of Cerebrum
• Frontal
• Parietal
• Temporal
• Occipital
• Insula
11-20
Functions of Cerebrum
• interpretation
• initiating voluntary movements
• storing memory
• retrieving memory
• reasoning
• center for intelligence and personality
11-21
Functional Regions of
Cerebral Cortex
Cerebral Cortex – thin layer of gray matter that constitutes the
outermost portion of cerebrum; contains 75% of all neurons.
11-22
Motor Areas
• Primary Motor Areas
• frontal lobes
• control voluntary muscles
• Broca’s Area
• anterior to primary motor cortex
• usually in one hemisphere
• controls muscles needed for speech
• Frontal Eye Field
• above Broca’s area
• controls voluntary movements of eyes and eyelids
11-23
Motor Areas
11-24
• Auditory Area
– temporal lobe
– interprets hearing
• Visual Area
–
–
–
–
occipital lobe
interprets vision
Cutaneous Sensory Area
interprets sensations on skin
Sensory Areas
11-25
Sensory Areas
11-26
Association Areas
• regions of cortex 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
11-27
Association Areas
Frontal Lobe Association Areas
• concentrating
• planning
• problem solving
• judging
Temporal Lobe Association Areas
• remember visual scenes
• remember music
• remember complex patterns
Parietal Lobe Association Areas
• understanding speech
• using words to express
thought
Occipital Lobe Association Areas
• combine visual images with
other sensory experiences
11-28
Hemisphere Dominance
• In over 90% of population, left hemisphere is dominant
• 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
11-29
Memory
Short Term
• working memory
• closed circuit
• circuit is stimulated over
and over
• when impulse flow
stops, memory disappears
Long Term
• changes structure
and function of
neurons
• enhanced synaptic
transmission
11-30
Basal Nuclei
• masses of gray matter
• deep within cerebral
hemispheres
• caudate nucleus, putamen,
globus pallidus
• produce dopamine
• control certain muscular
activities
11-31
Diencephalon
• between cerebral hemispheres and brainstem
• surrounds third ventricle
• thalamus
• hypothalamus
• optic tracts
• optic chiasm
• infundibulum
• posterior pituitary
• mammillary bodies
• pineal gland
11-32
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
11-33
Limbic System
Consists of
• portions of frontal lobe
• portions of temporal lobe
• hypothalamus
• thalamus
• basal nuclei
• other deep nuclei
Functions
• controls emotions
• produces feelings
• interpret sensory impulses
11-34
Brain Stem
Three Parts
1. Midbrain
2. Pons
3. Medulla Oblongata
11-35
Midbrain
• 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
11-36
Pons
• 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
11-37
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, vomiting)
11-38
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
11-39
Types of Sleep
Slow Wave
Rapid Eye Movement (REM)
• person is tired
• some areas of brain active
• decreasing activity of
• heart and respiratory rates
reticular system
irregular
• restful
• dreaming occurs
• dreamless
• reduced blood pressure and
respiratory rate
• ranges from light to heavy
• alternates with REM sleep
11-40
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
11-41
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
11-42
Structure of a Peripheral Nerve
11-43
Nerve Fiber Classification
• Sensory Nerves – conduct impulses into CNS
• Motor Nerves – conduct impulses to muscles or glands
• Mixed Nerves – contain both sensory nerve fibers and
motor nerve fibers; most nerves
General somatic efferent fibers
• carry motor impulses from
CNS to skeletal muscles
General somatic afferent fibers
• carry sensory impulses to
CNS from skin and skeletal
muscles
General visceral efferent fibers
• carry motor impulses away from
CNS to smooth muscles and
glands
General visceral afferent fibers
• carry sensory impulses to CNS
from blood vessels and internal
organs
11-44
Nerve Fiber Classification
Special somatic efferent fibers
• carry motor impulses from brain to muscles
used in chewing, swallowing, speaking, and
forming facial expressions
Special visceral afferent fibers
• carry sensory impulses to brain from olfactory and
taste receptors
Special somatic afferent fibers
• carry sensory impulses to brain from receptors of
sight, hearing, and equilibrium
11-45
Cranial Nerves
11-46
Cranial Nerves I and II
Olfactory (I)
• sensory
• fibers
transmit
impulses
associated
with smell
Optic (II)
• sensory
• fibers
transmit
impulses
associated
with vision
11-47
Cranial Nerves III and IV
Oculomotor (III)
• primarily motor
• motor impulses
to muscles that
• raise eyelids
• move the eyes
• focus lens
•adjust light
entering eye
Trochlear (IV)
• primarily motor
• motor impulses
to muscles that
move the eyes
11-48
Cranial Nerve V
Trigeminal (V)
• mixed
• opthalmic division
• sensory from surface of eyes,
tear glands, scalp, forehead, and
upper eyelids
• maxillary division
• sensory from upper teeth,
upper gum, upper lip, palate,
and skin of face
• 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
11-49
Cranial Nerves VI and VII
Abducens (VI)
• primarily motor
• motor impulses to
muscles that move
the eyes
Facial (VII)
• mixed
• sensory from taste
receptors
• motor to muscles of
facial expression,
tear glands, and
salivary glands
11-50
Cranial Nerves VIII and IX
Vestibulocochlear (VIII)
• sensory
• sensory from
equilibrium
receptors of ear
• sensory from
hearing receptors
Glossopharyngeal (IX)
• mixed
• sensory from
pharynx, tonsils,
tongue, and carotid
arteries
• motor to salivary
glands and muscles
of pharynx
11-51
Cranial Nerve X
Vagus (X)
• mixed
• 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
11-52
Cranial Nerves XI and XII
Accessory (XI)
• primarily motor
• motor to muscles of
soft palate, pharynx,
larynx, neck, and
back
Hypoglossal (XII)
• primarily motor
• motor to muscles of
the tongue
11-53
Spinal Nerves
• mixed nerves
• 31 pairs
• 8 cervical (C1 to C8)
• 12 thoracic (T1 to T12)
• 5 lumbar (L1 to L5)
• 5 sacral (S1 to S5)
• 1 coccygeal (Co)
11-54
Spinal Nerves
Dorsal root
• axons of sensory
neurons in the
dorsal root
ganglion
Dorsal root ganglion
• cell bodies of
sensory neurons
Ventral root
• axons of motor
neurons whose
cell bodies are in
spinal cord
Spinal nerve
• union of ventral root
and dorsal root
11-55
Dermatome
• an area of skin that the sensory nerve fibers of a particular spinal nerve innervate
11-56
Cervical Plexus
Nerve plexus – complex networks formed by anterior branches
of spinal nerves; fibers of various spinal nerves are sorted and
recombined
Cervical Plexus
• C1-C4
• lies deep in the neck
• supply muscles and
skin of the neck
• contribute to phrenic
nerve
11-57
Brachial Plexus
• C5-T1
• lies deep within shoulders
• musculocutaneous nerves
• supply muscles of anterior arms
and skin of forearms
• ulnar nerves
• supply muscles of forearms and
hands
• supply skin of hands
• radial nerves
• supply posterior muscles of
arms and skin of forearms and
hands
• axillary nerves
• supply muscles and skin of
superior, lateral, and posterior
arms
11-58
Lumbosacral Plexus
• T12 – S5
• extend from lumbar
region into pelvic cavity
• obturator nerves
• supply adductors of
thighs
• femoral nerves
• supply muscles and skin
of thighs and legs
• sciatic nerves
• supply muscles and skin
of thighs, legs, and feet
11-59
Autonomic Nervous System
• functions without conscious effort
• controls visceral activities
• regulates smooth muscle, cardiac muscle, and glands
• efferent fibers typically lead to ganglia outside CNS
Two Divisions
• sympathetic – prepares body for fight or flight
situations
• parasympathetic – prepares body for resting
and digesting activities
11-60
Autonomic Nerve Fibers
• all 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
11-61
Sympathetic Division
• thoracolumbar divison –
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
11-62
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
• preganglionic fibers to
adrenal medulla do not
synapse with postganglionic
neurons
11-63
Sympathetic Division
11-64
Parasympathetic Division
• craniosacral division –
location of preganglionic
neurons
• preganglionic fibers of the
head in III, VII, and IX
• ganglia are near or
within various organs
• preganglionic fibers of
thorax and abdomen in X
• short postganlionic
fibers
11-65
Parasympathetic Division
11-66
Autonomic Neurotransmitters
Cholinergic Fibers
• release acetylcholine
• preganglionic
sympathetic fibers
• preganglionic
parasympathetic
fibers
• postganglionic
parasympathetic
fibers
Adrenergic Fibers
• release
norepinephrine
• postganglionic
sympathetic
fibers
11-67
Actions of Autonomic
Neurotransmitters
• depend on receptor
Cholinergic receptors
• bind to acetlycholine
• muscarinic
• excitatory
• nicotinic
• excitatory
Adrenergic Receptors
• bind to
norepinephrine
• alpha
• different responses
on various effectors
• beta
• different responses
on various effectors
11-68
Actions of Autonomic
Insert figure 11.39
Neurotransmitters
11-69
Control of Autonomic
Activity
• Controlled largely by CNS
• Medulla oblongata regulates cardiac, vasomotor and
respiratory activities
• Hypothalamus regulates visceral functions
• Limbic system and cerebral cortex control emotional
responses
11-70
Life-Span 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 lobe has lost half its neurons
• Number of dendritic branches decreases
• Decreased levels of neurotransmitters
• Fading memory
• Slowed responses and reflexes
• Changes increase risk of falling
• Sleep problems common
11-71
Clinical Application
Cerebral Injuries and Abnormalities
Concussion
• brain jarred against cranium
• loss of consciousness
• temporary loss of memory
• mental cloudiness
• headache
• recovery usually complete
Cerebrovascular Accident
• stroke
• sudden interruption in blood
flow
• brain tissues die
Cerebral Palsy
• motor impairment
at birth
• caused by blocked
cerebral blood vessels
during development
• seizues
• learning disabilities
11-72