2. Receptor
Warm Up Sensory
Neuron
Effector
Central
Canal
( muscle
or
White
gland)
Matter
7
6 8
Grey
Matter
Motor
9 Neuron
Inter-
Cell
Neuron
Body of
Sensory
2
Impulse
4. Chapter 11
Nervous System II
Meninges
• membranes
surrounding CNS
• protect CNS
• three layers
• dura mater –
outer, tough
• arachnoid mater –
thin, weblike
• pia mater – inner,
very thin
4
6. 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
6
7. Cerebrospinal Fluid
• secreted by choroid
plexus
• circulates in ventricles,
central canal of spinal
cord, and subarachnoid
space
• completely surrounds
brain and spinal cord
• clear liquid
• nutritive and protective
• helps maintain stable ion
concentrations in CNS
7
8. Spinal Cord
• slender column of
nervous tissue
continuous with brain
• extends downward
through vertebral
canal
• begins at level of
foramen magnum
and terminates near
first and second
lumbar
8
15. Reflex Arc
• example crossed extensor reflex
• crossing of sensory impulses within the reflex center
to produce an opposite effect
16
16. 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
17
17. Ascending Tracts
• major ascending spinal
cord tracts
• fasciculus gracilis and
fasciculus cuneatus
• spinothalamic
• lateral and anterior
• spinocerebellar
• posterior and
anterior
18
18. Descending Tracts
• major descending spinal cord
tracts
• corticospinal
• lateral and anterior
• reticulospinal
• lateral, anterior and
medial
• rubrospinal
19
28. Structure of Cerebrum
• corpus callosum
• connects cerebral
hemispheres
• convolutions
• bumps or gyri
• sulci
• grooves
• longitudinal fissure
• separates hemispheres
• transverse fissure
• separates cerebrum from
cerebellum 29
29. Lobes of Cerebral Hemispheres
• Frontal
• Parietal
• Temporal
• Occipital
• Insula
30
30. Functions of the Cerebrum
• interpreting impulses
• initiating voluntary movements
• storing information as memory
• retrieving stored information
• reasoning
• seat of intelligence and personality
31
31. 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
32
32. Sensory Areas
• Cutaneous Sensory • Sensory Area for Taste
Area • near bases of the central
• parietal lobe sulcus
• interprets sensations
on skin • Sensory Area for
Smell
• Visual Area
• occipital lobe
• interprets vision • arise from
centers
deep within
• Auditory Area the cerebrum
• temporal lobe
• interprets hearing
33
34. 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
35
35. Association Areas
Frontal Lobe Association Areas Temporal Lobe Association Areas
• concentrating • interpret complex sensory
• planning experiences
• complex problem solving • store memories of visual scenes,
music, and complex patterns
Parietal Lobe Association Areas Occipital Lobe Association Areas
• understanding speech • analyze and combine visual
• choosing words to express images with other sensory
thought experiences
36
36. Motor Areas
• 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 37
39. Basal Nuclei
• masses of gray matter
• deep within cerebral
hemispheres
• caudate nucleus, putamen,
globus pallidus
• produce dopamine
• control certain muscular
activities
• primarily by inhibiting
motor functions
40
40. Diencephalon
• between cerebral hemispheres and above the brainstem
• surrounds third ventricle
• thalamus
• hypothalamus
• optic tracts
• optic chiasma
• infundibulum
• posterior pituitary
• mammillary bodies
• pineal gland
41
41. 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
42
42. Diencephalon
Limbic System
Consists of
• portions of frontal lobe Functions
• portions of temporal lobe • controls emotions
• hypothalamus • produces feelings
• thalamus • interprets sensory impulses
• basal nuclei
• other deep nuclei
43
44. 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
45
45. 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
46
46. 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, vomiting)
47
47. 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
48
48. 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
49
50. Warm up- Name cranial nerves and structures and
list the function of each cranial nerve on the back of paper.
1 7
2
8
3 9
10
11
4 12
5 13
14
6
15
51
51. 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
52
54. Nerve Fiber Classification
• Sensory Nerves – conduct impulses into brain or spinal
cord
• Motor Nerves – conduct impulses to muscles or glands
• Mixed Nerves – contain both sensory nerve fibers and
motor nerve fibers; most nerves
55
55. Nerve Fiber Classification
General somatic efferent fibers General somatic afferent fibers
• carry motor impulses from • carry sensory impulses to
CNS to skeletal muscles CNS from skin and skeletal
muscles
General visceral efferent fibers General visceral afferent fibers
• carry motor impulses away from • carry sensory impulses to CNS
CNS to smooth muscles and from blood vessels and internal
glands organs
56
56. 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
57
58. Cranial Nerves I and II
Olfactory (I) Optic (II)
• sensory • sensory
• fibers transmit • fibers transmit
impulses associated impulses associated
with smell with vision
59
59. Cranial Nerves III and IV
Oculomotor (III) Trochlear (IV)
• some sensory • some sensory
• proprioreceptors • proprioreceptors
• primarily motor • primarily motor
• motor impulses to • motor impulses to
muscles that muscles that move the
• raise eyelids eyes
• move the eyes
• focus lens
•adjust light entering
eye
60
60. 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
61
61. Cranial Nerves VI and VII
Abducens (VI)
• primarily motor
• motor impulses to
muscles that move
the eyes
• some sensory with
proprioreceptors
Facial (VII)
• mixed
• sensory from taste
receptors
• motor to muscles of
facial expression,
tear glands, and
salivary glands 62
62. Cranial Nerves VIII and IX
Vestibulocochlear (VIII)
Glossopharyngeal (IX)
• sensory
• mixed
• vestibular branch
• sensory from pharynx,
•sensory from
tonsils, tongue, and carotid
equilibrium receptors of
arteries
ear
• motor to salivary glands
• cochlear branch
and muscles of pharynx
•sensory from hearing
receptors
63
63. 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
64
64. Cranial Nerves XI and XII
Accessory (XI) Hypoglossal (XII)
• primarily motor • primarily motor
• cranial branch • motor to muscles of
• motor to muscles of the tongue; some
soft palate, pharynx, proprioreceptor
and larynx
• spinal branch
•motor to muscles of
neck, and back; some
proprioreceptor
65
66. 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)
67
67. Spinal Nerves
Dorsal root (posterior
or sensory root)
• axons of sensory
neurons in the
dorsal root
ganglion
Dorsal root ganglion
• cell bodies of sensory
neurons whose axons
conduct impulses inward
from peripheral body
parts
68
68. Dermatome
• an area of skin that the sensory nerve fibers of a
particular spinal nerve innervate
69
69. Spinal Nerves
Ventral root (anterior or
motor root)
• axons of motor
neurons whose cell
bodies are in spinal
cord
Spinal nerve
• union of ventral root
and dorsal root
70
70. Cervical Plexuses
Nerve plexus – complex networks formed by anterior branches
of spinal nerves; fibers of various spinal nerves are sorted and
recombined
Cervical Plexus
• formed by anterior
branches of C1-C4
• lies deep in the neck
• supply muscles and
skin of the neck
• C3 – C5 contribute to
phrenic nerves
71
71. Brachial Plexuses
• C5-T1
• lies deep within shoulders
• musculocutaneous nerves
• supply muscles of anterior arms
and skin of forearms
• ulnar and median 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
anterior, lateral, and posterior
arms 72
72. Lumbosacral Plexuses
• T12 – S5
• extend from lumbar
region into pelvic cavity
• obturator nerves
• supply motor impulses
to adductors of thighs
• femoral nerves
• supply motor impulses
to muscles of anterior
thigh and sensory
impulses from skin of
thighs and legs
• sciatic nerves
• supply muscles and skin
of thighs, legs, and feet 73
74. Cranial Nerve Assessment
http://www.youtube.com/watch?v=eLzkgPkgkEo
Detailed Cranial Assessment
http://www.youtube.com/watch?
v=G6FZR64Cq9U&feature=related
12 days of Christmas Cranial Nerve song
http://www.youtube.com/watch?v=4xzQ5vnvL-
o&feature=related
75
75. 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
76
76. Autonomic Nerve Fibers
• all are 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 77
77. 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
78
78. 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 79
80. Parasympathetic Division
• craniosacral division – • preganglionic fibers of the
location of preganglionic head are included in nerves
neurons III, VII, and IX
• ganglia are near or
• preganglionic fibers of
within various organs
• terminal ganglia thorax and abdomen are
parts of nerve X
• short postganglionic
fibers
• continue to
specific muscles or
glands 81
83. Actions of Autonomic
Neurotransmitters
• depend on receptors in the membrane
Cholinergic receptors Adrenergic Receptors
• bind to acetlycholine • bind to epinephrine
• muscarinic and norepinephrine
• excitatory • alpha and beta
• slow • both elicit different
• nicotinic responses on various
• excitatory effectors
• rapid
84
85. 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 86
86. 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 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
87
87. Clinical Application
Cerebral Injuries and Abnormalities
Concussion Cerebral Palsy
• brain jarred against cranium • motor impairment at
• loss of consciousness birth
• temporary loss of memory • caused by blocked
• mental cloudiness cerebral blood vessels
• headache during development
• recovery usually complete • seizures
• learning disabilities
Cerebrovascular Accident
• stroke
• sudden interruption in blood
flow
• brain tissues die
88
