Physiology 31 Lecture
Chapter 9 – Central Nervous System: Brain & Spinal Cord
I. Overview
A. Anatomy of the CNS
B. Spinal Cord
C. Brain
1. Cerebrum
2. Diencephalon
3. Brain Stem
4. Cerebellum
D. Higher Brain Functions
II. Anatomy of the Central Nervous System (CNS)
A. The CNS consists of the _______ and spinal cord
B. The CNS develops from a hollow _______ in an embryo
1. A fertilized egg cell (________) undergoes rapid mitotic cell divisions (_________),
which form the
a. _________ – solid ball of about 16-32 cells, which becomes a
b. _________ – hollow ball of many cells, which develops into the
c. ___________ – top of the blastocyst flattens into a neural plate, which curves inward
and forms a neural ______ that develops into the brain and spinal cord
2. The 3 ___________ divisions of the brain are the
a. _____brain – becomes the cerebrum and diencephalon
b. _____brain – becomes the cerebral peduncles and corpora quadragemini
c. ______brain – becomes the brainstem and cerebellum
C. The _____ is divided into gray and white matter
1. Cells of the CNS include _______ (esp. interneurons), and ____ cells
2. ______neurons are found between neurons (e.g., sensory and motor neurons) and allow
them to communicate with each other
3. _______ matter consists of ___myelinated nerve cell bodies, dendrites, and axon
terminals
a. Clusters of neuron cell bodies in the CNS are called ________
b. In the PNS, a group of neuron cell bodies is called a ________
4. _______ matter is composed mostly of ___________ axons that form bundles called
_______ (similar to nerves in the PNS) that interconnect regions of the CNS
D. Bone and connective tissue support the CNS
1. The cranium encases the _______, whereas the spinal cord is surrounded by the
vertebral column
2. Three layers of connective tissue, called the __________ enshroud the brain and spinal
cord. From outer to inner, the meninges are
a. _______ mater is the thickest layer, and is associated with veins that drain blood
through vessels or sinuses
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b. _____________ mater is a thin, web-like membrane
1) Sub_________ space is between the dura and arachnoid mater
2) Sub__________ space is between the arachnoid and pia mater, and contains
cerebrospinal fluid (_____)
3) A subdural or subarachnoid _________ is bleeding into the above spaces due to
head trauma, which can result in coma or death
c. _____ mater is a thin, vascular membrane that adheres to the surface of the brain and
spinal cord
3. ___________ is an inflammation of the meninges due to bacteria, viruses, or other
pathogens
E. Cerebrospinal fluid (_____) circulates in the ventricles of the brain, central canal of the SC,
and the sub___________ space of the CNS
1. CSF is a salty fluid secreted by _______ _______ (capillaries and ependymal cells) in the
brain ventricles
2. About 500 ml of CSF is produced a day, but only _____ ml (about ½ cup) is present at
one time
3. Composition is similar to blood ________, from which it is made, except it has more
____, H+, and Cl-, and less K+, Ca 2+, HCO3-, glucose, and _________
4. CSF serves 3 purposes
a. ___________ – CSF has similar density to the brain, allowing the brain to weigh
much less as it “floats” inside the cranium
b. _____________ – provides a fluid cushion for the brain if the head is jolted
c. Chemical ________ – it’s a means of rinsing metabolic wastes from the CNS and
maintenance of homeostasis in the chemical environment
5. A spinal (________) tap withdraws a small sample of CSF from the sub__________
space for analysis for bacteria, viruses, etc.
F. The _______-______ barrier protects the brain
1. The blood-brain barrier consists of tightly joined brain __________ endothelial cells
surrounded by __________; these tight junctions restrict what is allowed into the brain
a. Materials that cross the BBB include water, some electrolytes, _______, and lipidsoluble molecules, such as O2, CO2, alcohol, caffeine, nicotine, and anesthetics
b. Larger materials such as _______, some toxins (e.g., bacteria), and most drugs cannot
cross the BBB
2. The BBB protects the brain from _________ substances, but also interferes with
theraputic drugs administered to the brain
G. ___________ tissue has special metabolic requirements
1. The brain comprises 2% of body mass, but receives 15% of the blood supply and 20%
of the body’s oxygen and ________
2. Lack of _________ for a few minutes usually results in brain damage or death
3. ____________ is the main energy source for the brain
a. Glucose _________ in blood-brain barrier cells allow glucose to cross the BBB into
the brain
b. ______glycemia (high blood glucose) can lead to ______-regulation of the glucose
transporters
c. ______glycemia (low blood glucose) in diabetics can cause mental confusion, slurred
speech, coma, and even _______
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III. Spinal Cord
A. The ________ cord is composed of gray and white matter
1. ______ matter forms the central “H” shaped core of the SC; neurons involved in
spinal __________ are located here
a. ________ horns contain incoming sensory axons; the dorsal root extends outward
to the dorsal root _________, which contains ___________ neuron cell bodies
b. __________ horns contain cell bodies of autonomic _______ neurons
c. _________ horns contain somatic motor neuron cell bodies; the ventral root, with
_______ neuron axons extend outward
2. _____ matter surrounds the central gray matter, and consists of columns of
__________ ascending and descending nerve _____
a. __________ tracts, in the dorsal and lateral SC take ________ information to the
brain
b. ___________ tracts, in the ventral and deep lateral SC carry mostly _______
information from the brain to the cord
B. The spinal cord is divided into four regions, with 32 paired ______ _______ extending
laterally from united dorsal and ventral roots:
1. ________ has C1-C8 spinal nerves
2. __________ has T1-T12 spinal nerves
3. _________ has L1-L5 spinal nerves
4. _________ has S1-S5 spinal nerves
5. __________ nerves (C0) are found in the coccyx region
6. The rope-like spinal cord actually ends between ___ and ___, below this are branching
nerves called the cauda _________
C. Damage to the spinal cord can result in _____________, loss of ability to control muscles
IV. Brain
A. Major ________ regions include
1. __________ – largest, superior region, composed of five paired lobes within left and
right hemispheres
2. ____________ – central region consists of the thalamus, hypothalamus, pineal gland, and
pituitary gland
3. Brain ______ – extends downward from the diencephalon and consists of the midbrain,
pons and medulla oblongata
4. ____________ – posterior, inferior portion
V. Cerebrum
A. Consists of 5 paired ______ within left & right hemispheres. The cerebrum is involved
in higher brain functions, including:
1. Perception of ________ impulses and instigation of voluntary ________ responses
2. Neural ___________ takes place in the gray matter found in the cerebral cortex,
basal nuclei, and limbic system
3. ___________, thought, sleep, and reasoning abilities
4. Instinctual and _________ (emotional) functions
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5.
The two ___________ control opposite sides of the body and different brain functions
a. _______ controls analytical reasoning and language
b. _______ controls spatial and artistic intelligence
B. Each cerebral hemisphere has 3 main ________
1. A superficial _________ of gray matter
2. White matter nerve _______ deep to the cortex
3. Basal ________ gray matter deep within the white matter
C. Structure of the Cerebrum
1. Cerebral ________ - 2-4 mm thick surface layer composed of ______ matter;
contains billions of neurons
2. The cerebral cortex contains 3 main types of __________ areas:
a. _______ areas in the frontal lobe that control voluntary motor functions
b. __________ areas in the parietal lobes that provide for awareness of sensations.
c. __________ areas integrate information from different lobes for appropriate
actions (e.g., allow us to smell a rose, name it, and picture it)
D. _________ of the Cerebrum and their functions
1. _________ lobes - form the anterior portion of each cerebral hemisphere. Major
functional areas include:
a. ____________ cortex is involved in intellect, complex reasoning, personality,
and memories of plans & social roles
b. Precentral _______ - contains ______ areas (primary motor cortex & motor
association areas) involved in the control of voluntary _________
c. ________ area - a motor _________ area at the base of the precentral gyrus in the
______ hemisphere
2. _______ lobes - posterior to the frontal lobes. Functional areas:
a. Postcental _________ - contains _________ areas (primary somatosensory &
somatosensory association areas) that respond to incoming ________ from
cutaneous and muscular receptors
b. ____________ area, at the junction of parietal and temporal lobes in the left
hemisphere, is where unfamiliar words are sounded out
c. Primary ___________ cortex – receives taste impulses
d. __________ is a language difficulty resulting from lesions (damage) in the
Wernicke’s and/or Brocas areas.
3. ___________ lobes - inferior to parietal lobes; contains the
a. __________ areas (primary auditory cortex and auditory association area) in the
superior temporal gyrus; receives auditory fibers (of CN VIII) from the ear cochlea
for _______
b. ___________ (smell) cortex in the medial temporal lobes and the inferior frontal
lobes, receives and processes sensory information from the olfactory tracts of CN
__
c. _________ of vocabulary, faces, and familiar objects is found in the superior
temporal lobe
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4.
____________ lobes - posterior cerebrum
a. Superior to the __________
b. ________ areas (primary visual cortex and visual association area) here integrate
_____ movements and correlate visual images (from CN ___) with other sensory
stimuli
5. The _______ is a medial structure deep within the lateral sulcus. It is thought to
integrate other cerebral activities and be involved in language, taste, and the sense of
balance, as well as integrating sensory information from visceral receptors
E. ______ matter of the cerebrum - three types of nerve ________ named according to
location and direction they conduct impulses
1. ___________ fibers - conduct impulses between neurons within a hemisphere (e.g.:
fibers between Broca’s & Wernicke’s areas)
2. _____________ fibers - connect the neurons & gyri of one hemisphere with those of
the other (e.g.: corpus callosum)
3. ____________ fibers - form the ascending and descending tracts of the brain & spinal
cord.
F. ______ matter deep to the cerebral white matter includes the basal nuclei and limbic
system
1. Basal ________ - specialized paired masses of gray matter that arch around the
thalamus
a. Basal nuclei inhibit involuntary ________ movements, and consist of the corpus
striatum and amygdala nuclei
b. These nuclei receive input from the substantia _______ (in the midbrain) and
_______ areas of the cerebral cortex and send signals back to both
c. Damage to the basal nuclei causes motor movement dysfunction, such as that found
in _________’s & Huntington’s diseases
2. ___________ System – a loop of grey matter around the corpus callosum and thalamus;
includes the amygdala and hippocampus. Functions
a. The _________, is considered to be part of the _________ brain, with a role in
emotional memories, as well as feelings of pleasure, love, anger, fear, and pain.
b. The ________ acts in memory consolidation, organizing sensory and cognitive
experiences into unified long-term ___________, which are then stored in the
temporal and frontal lobes
VI. The _____________ contains centers for homeostasis, and consists of the thalamus,
hypothalamus, pineal and pituitary glands
A. ____________ – gateway to the cerebral cortex, located just below the corpus callosum
1. Contains nuclei that serve as ________ stations for nearly all _________ impulses to
appropriate regions of cerebral cortex
2. Receives input from regions of the cerebrum involved in _______ control
3. Is interconnected with the _________ system, thus is involved in emotional and
memory functions
4. Also involved in arousal, eye movements, taste, smell, hearing, equilibrium, and
_____________ input
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B. ___________, located just below the thalamus is a major regulator of bodily
____________. Functions include
1. Control of _____ - controls and integrates the ANS, which regulates contraction of
smooth muscle, cardiac muscle, and glandular secretions.
2. Control of ___________ Gland via hypothalamic hormones
3. Regulation of _________ & behavior - rage, aggression, pain, pleasure, and sexual
arousal
4. Regulation of __________, thirst, & satiety
a. Neurons of hunger and satiety centers monitor _______ and amino acid levels for
hunger and _________ (fullness)
b. _______receptor neurons in hypothalamus monitor osmotic pressures and stimulate
the thirst center when thirsty; dehydration stimulates release of vasopressin (____)
c. _______regulation - control of body temperature via nuclei in heat-losing center
and heat-producing center, which control vasodilation, vasoconstriction, sweating,
___________
5. _______ control - the superchiasmatic nucleus establishes 24 hr. (circadian) sleep
patterns.
6. _______ – mamillary bodies are part of a signaling pathway from the hippo________ (a
memory center) to the thalamus
C. __________ and pineal glands are endocrine glands that were discussed during the
endocrine system unit
VII. Brain _____ - primitive brain region involved in ______ life functions; extends downward
from the diencephalon, and includes the midbrain, pons, and medulla oblongata
A. Ten of the 12 _______ nerves originate from the brain stem, and carry information to
and from the brain (see Table 9-1 for functions)
1. CN I, II, VIII all carry ________ information to the brain
2. CN III, IV, VI, XI, XII carry mostly ______ information from the brain to the spinal
cord
3. CN V, VII, IX, X are ______ nerves, carrying both sensory and motor information to
and from the brain
C. The _________ contains the cerebral peduncles and corpora quadrigemini
1. Corpora quadrigemini (posterior) – consists of the superior and inferior ________
a. Superior colliculi function in _______ reflexes
b. Inferior colliculi are involved in ________ reflexes
2. Cerebral __________ (anterior) pair of structures composed of ascending and
descending nerve ________ that connect to the cerebrum to other parts of the brain
3. _____ nucleus (middle) - connects cerebrum & cerebellum; concerned with fine
_______ control
4. Substantia _______ - inferior to the red nucleus
a. Is a motor center that relays inhibitory signals (via ________) to the thalamus and
basal _________
b. Inhibits forced ________ movements (affected in Parkinson’s disease)
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D. ______ – between the midbrain and medulla oblongata
1. Consists of white fiber ______ that connect it with the thalamus, cerebellum and
__________ oblongata (MO)
2. Nuclei of the pons function with those of the MO to regulate _________
E. ___________ oblongata – between the pons and spinal cord
1. _______ matter contains somatosensory and corticospinal tracts
a. _____________ (pyramidal) descending nerve tracts (from the ______ cortex) crossover (decussate) in the medulla oblongata; thus the right brain controls the _____ side
of the body and the left brain controls the ________ side
b. Somato__________ ascending nerve tracts pass through the medulla, pons, and
midbrain on their way to the ___________, then to the somatosensory cortex
2. ______ matter include nuclei that function as ____________ motor centers for the
control of visceral function, such as
a. ________ center – adjusts the force and rate of the heartbeat
b. ____________ center - sends impulses via the SC and spinal nerves to _________
walls, causing them to constrict and elevate BP
c. ____________ center - controls the rate and depth of breathing
d. Other MO nuclei are involved in sneezing, coughing, salivation, swallowing, sweating,
and ___________
F. ____________ activating system – a functional network of nuclei and nerve tracts in the
brain stem; functions include
1. Somatic _____ control- helps the cerebellum to maintain muscle tone and produce
coordinated contractions of skeletal ________
2. ___________ control – includes the cardiac center and vasomotor center of the MO
3. _______ modulation – origin of descending analgesic pathways of the reticulospinal
tracts
4. Sleep & ___________ – has projection tracts to the thalamus and cerebral cortex; acts
as a “gatekeeper” that decides what ________ information comes to our conscious
attention
VIII. _______________ (little brain) - second largest brain structure
A. The main function of the cerebellum is to ____________ skeletal muscle contractions and
process sensory impulses from proprioceptors within muscles, tendons, and joints
B. _________ input comes from neurons in the cerebral cortex
C. Also receives __________ input from receptors for balance and equilibrium in the inner
_____
IX. Higher Brain Functions involve complex activities, such as sleep, memories, cognition,
emotion, sensation, motor control, and language
A. Brain _______ & sleep
1. Brain waves are rhythmic changes in voltage that can be recorded on an
electroencephalogram (____).
2. Four types of brain waves are
a. _____ waves occur in the parieto-occipital area when a person is ______ and resting
with the eyes closed; also during _____ (rapid eye movement) sleep
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b. ______ waves occur in the frontal to parietal regions during mental ____________
and sensory stimulation
c. ________ waves are found in normal children and sleeping adults; in awake adults
they suggest brain abnormalities
d. _______ waves are seen in infants when awake and adults during _____ ______; in
awake adults, they indicate brain damage
B. _________ – includes awareness, perception, thinking, knowledge, and memory.
1. Brain ________, or local brain injuries, caused by infection, trauma, cancer, and
stroke, lead to damage in association areas of the brain, such as
a. _________ lobe lesions can cause people to become unaware of body parts on one
side of the body
b. Temporal lobe lesions may cause _________, the inability to recognize, identify,
and name familiar objects
c. Frontal lobe lesions can alter a person’s ___________
2. In general, _________ areas of the above lobes are responsible for different areas of
cognition
a. Parietal – perceives ___________ stimuli
b. Temporal – identifies the stimuli (via __________)
c. Frontal – plans and initiates the __________ to the stimuli
C. ____________ is the ability to retain and recall information
1. The physical basis of a memory is a pathway through the brain called a memory ______,
in which new synapses form or existing synapses are modified
2. Two types of memory include
a. ______-term memory – lasts from seconds to hours and is limited to a few bits of
information; processed in the ______ lobe
1) _________ memory allows us to keep an idea in memory long enough to carry out
an action (e.g., calling on the phone)
2) Short-term memory will disappear unless an effort, such as __________, is made to
put them into long-term memory
b. ______-term memory lasts up to a lifetime, and often involves the physical
remodeling of __________ or the formation of new ones through the growth and
branching of axons and dendrites
X. CNS Disorders
A. Cerebral _______ – muscular incoordination due to damage to the motor areas of the
brain during fetal development; caused by measles exposure, drugs, radiation, oxygen
deficiency, hydro________ (water on the brain)
B. ___________ – symptoms include massive discharge of neurons (seizures), resulting in
convulsions, sensory and psychic disturbances, and often impaired consciousness
C. ____________ – brain damage due to a blow, often with loss of consciousness, blurred
vision, and sometimes short-term amnesia
D. Stroke (_____) – occurs when blood circulation to a brain area is blocked and the brain
tissue dies
E. _________ disease – mental dementia caused by the development of β-amyloid protein
_________ around degenerated neurons and neurofibrillar (tau) __________ within
neuron cell bodies