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Ch. 13 Central Nervous System
I.
Coverings of CNS (Figs. 13-2, 13-3)
A.
Bone (Cranium & Vertebrae)
B.
Meninges - membranes; 3 layers
1.
________ _________ (Figs. 13-2, 13-3)
a.
strong ___________ fibrous tissue
b.
outer layer & also forms inner periosteum of
cranial bones
c.
Falx cerebri (Fig. 13-2) - inward extension
1)
Superior sagittal sinus - b/t 2 _______
hemispheres
2.
d.
Falx ________ - inward ext that separates 2
halves of cerebellum
e.
Tentorium cerebelli -separates cerebellum
from ________________
f.
____________ space - outside dura mater but inside bony
coverings
Arachnoid membrane (Figs. 13-2, 13-3)
a.
delicate, cobweb-like layer
b.
subdural space - between _______ _______ and arachnoid
membrane
c.
________________ space - under arachnoid & outside pia
mater
1)
3.
C.
contains CSF
__________ ___________ (Figs. 13-2, 13-3)
a.
adheres to outer surface of brain & sp cord
b.
delicate c.t., minute blood vessels
a.
Filum terminale (Fig. 13-1) - slender
filament at S3 level; blends w/ dura mater to
form cord that disappears w/ periosteum of
coccyx
Meningitis - inflammation of _________________
1.
Most often involves __________ & pia meninges
2.
Causes - ________________ (m/c), viral, fungus
1
II.
3.
S/sx - ___________, severe HA, stiff ________
4.
Dx - CSF sample from subarachnoid space
Cerebrospinal Fluid
A.
Liquid cushion; similar to plasma
B.
Reservoir of circulating fluid  brain monitors for chgs in internal
environment
C.
Fluid spaces (p. 377)
1.
_________________ space
2.
Central canal of sp cord
3.
Ventricles (Fig. 13-4) - 4
a.
Lg. fluid filled spaces w/in brain
b.
Interconnected w/ each other & canal of sp.
Cord
c.
Lined w/ ependymal cells
d.
Lateral ventricles
e.
f.
1)
C-shaped
2)
In each hemisphere of the _________
3rd Ventricle
1)
In diencephalons
2)
Interventricular foramen- opening to
lateral ventricle
4th Ventricle- where the _________ attaches
to the back of the _______________.
1)
Cerebral Aqueduct- Connects 3rd &
4th, Runs through midbrain
D.
Formation & Circulation of CSF (Fig. 13-5)
1.
Choroid plexus
a.
network of capillaries that project from pia mater into
_________ ___________ & into roofs of ________ & 4th
ventricles
b.
forms CSF from blood plasma
2
c.
E.
III.
covered w/ sheet of ____________ cells 
release CSF into spaces
2.
Arachnoid villi - returns CSF to blood
3.
Circulation pathway (Fig. 13-5)
a.
lateral ventricle  seeps thru opening,
_____________ foramen  3rd ventricle 
b.
through channel, ____________ aqueduct  4th
ventricle
c.
central canal of cord
d.
some from 4th ventricle  cisterna magna, a space
continuous w/ ______________ space  venous blood
_______ ml - Avg. amt. of CSF in adult
Spinal Cord (p. 380)
A.
Structure of the spinal cord (Fig. 13-6)
1.
Location (Fig. 13-1)
2.
Transverse sectional structure (Figs. 13-6,
13-7)
3.
Gross structure (Fig. 13-7)
a.
dorsal nerve root- carries ________
information to the spinal cord
b.
ventral nerve root- carries ________
information out of the spinal cord
B.
Functions of the spinal cord- provides conduction
routes to and from the ________ and serves as the integrator or
___________ center
1.
Ascending tracts (Fig. 13-7; Table 13-1)conduct ____________ impulses up the cord to the brain
a.
Lateral spinothalamic tracts- crude
touch, pain, and ____________
b.
Anterior spinothalamic tracts- crude touch and
_____________
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2.
IV.
c.
Fasciculi gracilis and cuneatus- discriminating
touch and ___________ sensation of position and
movement of body parts
d.
Spinocerebellar tracts- ____________ kinesthesia
Descending tracts (Fig. 13-7; Table 13-2)- conduct
__________ impulses down the cord from the brain
a.
Lateral corticospinal tracts- voluntary movement of
__________ side of body
b.
Anterior corticospinal tracts- voluntary movement
of __________ side of body
c.
Reticulospinal tracts- help maintain ___________
during skeletal muscle movements
d.
Rubrospinal tracts- transmits impulses that
coordinate body movements and maintenance of
posture
The Brain (p. 383)
A.
Major divisions (Fig. 13-8)
1.
a.
Medulla oblongata- lowest part
b.
Pons- in between/ in the middle
c.
Midbrain- uppermost part
2.
___________________
3.
Diencephalon
4.
B.
Brainstem
a.
Thalamus
b.
________________
c.
Epithalamus- includes the pineal body/ gland
Cerebrum
Structure of the brainstem
1.
Medulla oblongata (Fig. 13-9)
a.
Connects brain to sp. Cord
b.
Extension of sp cord above ___________
_____________
c.
Composed of _________ ___________ (projection tracts)
& a network of gray & white matter called the _______
_______
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d.
Pyramids (Fig. 13-9)
1)
Two bulges of white matter located on
____________ surface
2)
Made up of pyramidal tracts
descending from motor cortex
e.
Olive (Fig. 13-9) - oval projection on each
side of ventral surface of medulla, lateral to
_____________
f.
Nuclei - in reticular formation, clusters of
neuron cell bodies
1)
2.
3.
Pons (Fig. 13-9)
a.
B/t midbrain & medulla ob.
b.
Composed of ___________ matter & reticular formation
c.
External white matter - fibers run
transversely across pons, thru middle
cerebellar peduncles  cerebellum
Midbrain (___________________) (Fig. 13-9)
a.
Between _______________ & pons
b.
Cerebral peduncles (Fig. 13-9)
c.
d.
1)
Bulges of white matter
2)
tracts conduct impulses b/t _____________ &
cerebrum
Corpora quadrigemina (Fig. 13-9, B) - lg
nuclei in midbrain
1)
2 Inferior colliculi - _________ centers
2)
2 Superior colliculi - ________ centers
Red nucleus (Fig. 13-11; Fig. 13-22)
1)
e.
C.
Vital centers/ control centers
Nucleus involved in muscular control
Substantia nigra (Fig. 13-15)
2)
Nucleus involved in muscular control
3)
Dark pigment in nucleus
Functions of the brainstem (p. 386)
1.
Performs sensory, motor, and __________
functions
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2.
Important tracts pass through to other parts of the brain;
other tracts terminate on brainstem
3.
Medulla oblongata reflex center nuclei
a.
b.
Vital centers
1)
Cardiac center- force & rate of
heart contraction
2)
______________ center - BP (vessel
diameter)
3)
Respiratory center - Rate/depth
of breathing
Nonvital centers
1)
4.
5.
Pons reflex centers
a.
____________ center - helps maintain
normal breathing rhythms
b.
For cranial nerves V, VI, VII and VIII.
Midbrain reflex centers
a.
D.
Vomiting, coughing, _________,
hiccuping, and swallowing
Nuclei for cranial nerves III (_______
reflexes) and IV (______ movements)
Cerebellum -Structure (Fig. 13-10)
1.
_________ Fissure - separates from the cerebrum
2.
Cortex - outside; gray matter
3.
White matter predominates interior
4.
_________ _________ - "Tree of Life"; pattern of white matter
5.
Sulci (grooves) and __________ (raised areas)
6.
Vermis - separates 2 hemispheres of the cerebellum
7.
Cerebellar peduncles (Fig. 13-9) - contains long
tract fibers
a.
Inferior cerebellar peduncles - tracts that
come into cerebellum from __________ and cord
1) Ex. Spinocerebellar
b.
Middle cerebellar peduncles - tracts to
__________________ from pons
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1)
c.
8.
Superior cerebellar peduncles - tracts from
dentate nuclei (cerebellum)  red nucleus
(midbrain)  _________________
Dentate nuclei
a.
E.
nuclei in each hemisphere that communicate w/ motor
cortex of ________________ cortex & thalamus
Functions of the cerebellum (Fig. 13-11)
1.
2.
Coordinates skilled movements
a.
Works w/ _________ __________ to produce
skilled movements
b.
Coordinates activities of groups of
muscles
Helps control posture
a.
3.
F.
Pontocerebellar tracts
functions to make movements __________, steady,
and efficient at the subconscious level
Controls skeletal muscles for ___________
a.
sensory impulses from equilibrium
receptors (ear)  cerebellum
b.
cerebellum  motor fibers for
contracting muscles for stabilization
Diencephalon- located between the cerebrum and the midbrain (p. 388) thalamus, ___________________, epithalamus
1.
Thalamus (Figs. 13-8, 13-12, 13-15)
a.
Structure
1)
80% of diencephalon
2)
Lateral masses - mass of gray matter;
form wall of _______ ventricle
a)
3)
b.
Geniculate bodies - grp of nuclei
that play a role in processing
_______________ & visual input
Joined by Intermediate mass (Fig.13-9)
Function
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1)
2.
Relay station for sensory impulses  primary
sensory areas of Cerebral cortex
a)
Conscious recognition of
sensations (pain, _______, touch)
b)
All senses, but ______________
c)
Relay of sensory action
potentials to cerebrum
2)
Association of sensations with feelings
of ____________ and _____________
3)
Part of arousal and _______________ mechanism
4)
Part of complex _______________ mechanism
Hypothalamus (Figs. 13-8, 13-12) - beneath
thalamus; forms inferiorlateral walls of 3rd ventricle
a.
Structure
1)
Supraoptic nuclei
a)
2)
Gray matter above & either side
of optic chiasma
Infundibulum
a)
Stalk leading to posterior lobe of
__________________ gland (neurohypophysis)
4)
b.
Mamillary bodies
a)
Posterior part of hypothalamus
b)
Involved in olfactory sense
Function - important in homeostasis
1)
Autonomic center - main visceral
control center of body
a)
2)
3)
Regulator & coordinator of
autonomic activities.
Link between mind and body
a)
Major relay station b/t _______ _______ &
lower autonomic ctrs
b)
Route by which emotions can express
themselves in changed ____________
functions
Synthesis neurohypophyseal hormones
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a)
4)
5)
Secretion of releasing hormones
a)
Axons secrete chemicals = releasing
hormones
b)
Control release of certain anterior pituitary
hormones, ex. _______ hormone
Part of arousal or alerting
mechanism
a)
6)
Maintaining the ________ state
Appetite center
a)
7)
Hormones affect urine volume _______ but
do play an essential role in maintaining
water balance
Regulating appetite and "satiety
center"
_______________ control site
a)
Neurons whose fibers connect w/
autonomic centers for vasoconstriction,
__________, & sweating
3.
Pineal body (Figs. 13-8; 13-9, B; 13-12)
a.
Structure
1)
Part of the epithalamus
a)
2)
b.
G.
Most dorsal of diencephalons
Located superior to corpora
quadrigemina
Function
1)
Regulation of ____________ clock
2)
Production of ________________
Structure of the cerebrum (p. 390)
1.
60% of brain wt
2.
2 halves - L & R cerebral hemispheres
3.
Cerebral cortex
a.
gray matter
b.
2-4 mm thick
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c.
many convolutions (gyri)
1) precentral gyrus, ____________ gyrus,
cingulated gyrus, & _______________
gyrus
4.
d.
______________ - shallow grooves
e.
______________ - deeper grooves
1)
Forms 5 lobes/hemisphere: frontal,
________, temporal, ________, insula
2)
Lobes named for cranial bone, except insula
3)
Longitudinal fissure - separates
hemispheres of _______________
4)
Central sulcus - groove b/t _________ & parietal
lobes
5)
Lateral fissure outlines temporal lobe; insula
(island of _______ lies deep in lat. Fissure)
6)
________________ fissure - separates
occipital lobe from parietal lobe
Cerebral White Matter (Cerebral tracts and
cerebral nuclei)
a.
Tracts (Fig. 13-14) - 3 types
1)
Projection tracts
a)
2)
3)
b.
Extensions of ascending
spinothalamic tracts &
descending ___________ tracts
________________ tracts
a)
Most numerous
b)
Impulses b/t gyri w/in single
hemisphere
Commissural tracts (corpus callosum) (Fig. 13-12)
a)
Connect corresponding regions
of 2 hemispheres
b)
Compose the corpus callosum largest
Cerebral Nuclei (Fig. 13-15) - islands of
gray matter deep inside white matter (basal
ganglia) of each cerebral hemisphere
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1)
_____________ nucleus
a)
2)
3)
4)
Lentiform nucleus
a)
lens like
b)
putamen & globus __________
_________________ nucleus
a)
_____________-shaped
b)
tip of caudate nucleus
Regulating voluntary ______ functions
a)
H.
comma-shaped
Initiates mm contractions in maintaining
______________, walking or other
repetitive movements
Functions of the cerebral cortex (p. 393)
1.
2.
Functional areas of the cortex (Figs. 13-16, 13-17)
a.
Certain areas usually have 1 particular function =
____________ localization
b.
Each hemisphere - opposite sides of body
c.
Hemispheres not exactly = in function
Sensory functions of the cortex (Figs. 13-16; 13-17, A)
a.
Somatic senses - touch, temp, pain, propioception
b.
Special senses - visual, hearing
c.
Postcentral Gyrus - primary somatic ___________ area
1)
Parietal lobe; behind central sulcus
2)
General somatic senses
3)
Size relates to # of sensory receptors (fig.13-17)
d.
Transverse gyrus - Primary __________ area & Auditory
association area
e.
Somatosensory association area - "body
perception; many connections w/ prim sensory cortex
f.
Visual cortex
1)
____________ lobe
2)
Surrounded by Visual Association Area
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g.
3.
Wernicke's Area
1)
Left temporal lobe
2)
Comprehension of written & spoken
language
Motor functions of the cortex (Figs. 13-16; 13-17, B)
a.
Precentral gyrus
1)
Primary somatic ____________ area
2)
Voluntary skeletal movements
3)
Pyramidal tracts (___________ tracts)
& all other descending motor tracts
4)
Homunculus - "little man)
a)
b.
c.
4.
Entire body represented on each
hemisphere; distorted image
Premotor cortex
1)
Anterior to primary motor cortex
2)
Thought to activate groups of ______
simultaneously
3)
Learned repetitive movements like typing
Broca's area
1)
Motor speech
2)
Articulation of words
3)
Damage (aphasias) - unable to
articulate, but can make vocal sounds
& understands words heard/read
Integrative functions of the cortex
a.
Consciousness (Fig. 13-18)
1)
Reticular Activating System
a)
Network of neurons
b)
Consists of centers of reticular
formation in ______________
c)
Impulses from sp. Cord
_______________  all parts of cerebral
cortex
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d)
w/o excitation of cortical neurons 
_________/cannot be arousal
e)
functions:
1. arousal or _________ system
2. maintaining _____________
f)
Drugs
1. Depress the Reticular Activating
System- induces sleep, ex.
_____________
2. Stimulates the cerebrum- stimulates the
Reticular Activating System, enhances
alertness and keeps you awake, ex.
______________
b.
c.
5.
V.
Memory
1)
Short term & long term
2)
Temporal, ________, & occipital lobes
3)
_____________ - permanent change in synapses in
a specific circuit of neurons
4)
Limbic system also plays a key role in memory
Limbic System "Emotional Brain”
1)
Curving border @ corpus _________;
includes cingulated gyrus & hippocampus
2)
Many connections w/ higher & lower brain center
3)
Functions with other parts of the cerebral cortex to
enable us to experience emotions such as _______,
fear, sexual feelings, _____________, and sorrow
Specialization of cerebral hemispheres (p. 396)
a.
R & L specialize in __________ functions
b.
L - language; dominate the control of hand
movements like _________; & logic (math)
c.
R - certain auditory stimuli (___________, coughing,
crying); tactile perception; creative (perceiving and
visualizing spatial relationships)
Somatic Sensory Pathways in the CNS
A.
(Fig. 13-21)
Primary sensory neurons - axons conduct from
periphery to dendrites & cell bodies in CNS (sp cord)
13
VI.
B.
Secondary sensory neurons - axons ascend (ascending
tracts) from spinal cord or brainstem thalamus 
C.
Dendrites & cell bodies of Tertiary sensory neurons 
axons conduct to sensory areas in cortex
D.
Most axons of secondary neurons decussate (cross from one side to
another) before reaching the ____________
E.
Ex. Medial lemniscal system (discriminating touch and pressure, precise
localization, 2-point discrimination, weight discrimination, and sense of
vibration) & _______________ pathway (crude touch and pressure)
Somatic Motor Pathways in the CNS
A.
B.
Pyramidal tracts (______________ tracts) (Fig. 13-22)
1.
Fibers that come together in pyramid (medulla)
2.
AKA corticospinal tracts
3.
3/4 decussate in _____________
4.
Fibers usually synapse w/ interneurons  synapse w/ anterior horn
motor neurons 
5.
Stimulation of _____________ muscle groups- mainly hands and
feet
6.
Damage to anterior horn  _____________
7.
Poliomyelitis -destroys anterior horn motor neurons
8.
CVA- cerebrovascular accident or strokes
Extrapyramidal tracts (Figs. 13-22, 13-23)- consist of all motor tracts from
the brain to the anterior horn of the spinal cord except the corticospinal
tracts
1.
VII.
(Fig. 13-22)
Function- contracts muscle groups in sequence or
_______________, ex. Swimming, ___________,
______________, or frowning
Mechanisms of Disease (p. 404)
A.
Destruction of brain tissue
1.
__________________ accident (CVA) (Figs. 13-16, 13-17, 13-22)
a.
Stroke
b.
Destruction of neurons in motor cortex
c.
Cz - hemorrhage or blood clot
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d.
Cannot voluntarily move body parts
controlled by affected area
e.
_____________ side of body
f.
_________________ - paralysis one whole side of body
2.
Cerebral Palsy- permanent, nonprogressive damage to __________
control areas of the brain, occurs prior to or shortly after birth
3.
Dementia- destruction of neurons of the brain
a.
b.
4.
B.
________________ disease (AD)
1)
Lesion (plaques) in cortex middle/late life
2)
Cz - unknown; may be genetic
________________ disease (HD)
1)
Inherited disease
2)
Begins w/ chorea (______________, purposeless
movements)  dementia, then death
3)
Onset _____-____; death ~55
4)
Protein, ________ is made incorrectly, thus it
prevents normal brain function
AIDS- acquired immune deficiency syndrome caused by HIV
(human immunodeficiency virus)- infection of white blood cells,
can also cause dementia
______________ disorders
1.
Seizure - sudden bursts of abnormal neuron
activity that result in temporary changes in the brain
2.
Epilepsy (Fig. 13-24) - recurring/____________ seizures
a.
Cz - tumor, chemical imbalance, m/c
_____________
b.
Dz tools - Electroencephalography (_____) measure voltage of brain activity
c.
Tx - medications, surgery
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