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Nervous System Study Guide: Ch. 12, 13, &14
1. Draw a neuron and label the dendrite, cell body, axon, axon terminal, axon hillock,
Schwann cells, and nodes of Ranvier.
2. List the 2 anatomical divisions of the nervous system and the organs or tissue they
contain.
3. Compare and contrast the afferent and efferent divisions of the PNS as well as the
somatic and autonomic nervous systems of the efferent division.
Afferent: Sensory
Efferent: Motor
Somatic: Skeletal Muscles are Effectors
Autonomic: Involuntary Muscles are Effectors
4. Describe each of the following structural classification of neurons. Circle the most
common.
a. Anaxonic: small and can’t distinguish axons from dendrites, not myelinated
b. Bipolar: one dendrite and one axon with a cell body in between, no myelin
c. Unipolar: the dendritic and axonal process are continuous, may be myelinated
d. Multipolar : most common several dendrites and a single axon, may be myelinated
5. List the four types of Neuroglial cells and their function:
a. Astrocytes-their functions include the following:
1) Producing neurotransmitters
2) Maintaining potassium levels in the CNS-this aids in the production of
nerve impulses.
3) These help to form the blood-brain barrier which regulates the entry of
materials into the brain.
4) Connects neurons and blood vessels together.
b. Oligodendrocytes-produce myelin sheaths in the CNS.
c. Microglia-phagocytic cells derived from monocytes (specialized leukocytes).
1) These protect the CNS by engulfing microbes and foreign debris.
d. Ependymal Cells-are epithelial cells.
1) Many of these are ciliated.
2) These cells line the ventricles (cavities) within the brain. Ependymal
cells are involved in the production of cerebrospinal fluid
6. Draw a synapse and label the presynaptic membrane, postsynaptic membrane,
mitochondrion, synaptic cleft, and vesicles.
7. Explain a cell membranes resting potential in terms of Na and K exchange as well as
internal and external membrane charges.
At rest Na+ is being pumped out of the cell and K+ is being pumped in. This creates an
negative internal and positive external membrane charge.
8. Define the following.
a. Graded potential-depolarizing or hyperpolarizing of membrane without a threshold
value, effect on membrane potential decreases with distance from site of
stimulation.
b. Depolarization-shift in transmembrane potential towards 0mV or above
c. Repolarization-restoring normal resting potential after depolarization
d. Hyperpolarization-a shift in resting potential that is increasingly negative
e. Action potential-changes in the transmembrane potential that spread across the
entire membrane
f. Threshold-the amount of stimulus required to activate an action potential
9. Create a line graph and label the above including resting potential in a typical action
potential generation.
10.What is the difference between continuous and salutatory propagation?
Continuous occurs in unmyelinated axons, salutatory occurs when the axons are
myelinated and the action potential must jump from node to node down the axon.
11.What is a neurotransmitter? What is the difference between an excitatory
neurotransmitter and an inhibitory neurotransmitter? Give an example of each?
A neurotransmitter is a chemical that is released at a synapse to propagate a nerve impulse
between cells.
Excitatory increases the action potential generation while inhibitory neurotransmitters cause
hyperpolarization and depress action potential generation.
12.Draw and label a cross section of a typical spinal cord segment. Label afferent and
efferent pathways.
13.List the layers of the spinal meninges from outside in.
Dura mater
Arachnoid mater
Pia mater
14.What is the difference between white matter and gray matter?
White matter is myelinated axons, white gray matter is unmyelinated cell bodies.
15.List the 4 nerve plexuses and the general body locations they innervate.
Cervical plexus - serves the head, neck and shoulders
Brachial plexus - serves the chest, shoulders, arms and hands
Lumbar plexus - serves the back, abdomen, groin, thighs, knees, and calves
Sacral plexus - serves the pelvis, buttocks, genitals, thighs, calves, and feet
16.Define and reflex and give the 5 components of a reflex arc.
Rapid automatic responses to stimuli. 1. Receptor 2. Sensory Neuron 3. Information
processing 4. Motor Neuron 5. Effector response
17.Describe the difference between a Somatic and Autonomic reflex and give an example of
each.
Somatic effector is skeletal muscle like in the patellar reflexes
Autonomic the effector is smooth muscle as in the pupillary reflex.
18.What are the 2 possible processing sites for a reflex?
Brain or Spinal Cord
19.Give an example of a Monosynaptic reflex.
Only one synapse as in the knee jerk patellar reflex
20.Give an example of a Polysynaptic reflex.
More than one synapse as in a withdrawal reflex.
21.Compare and contrast a contralateral and ipsilateral reflex.
Ipsilateral reflex is a reflex that effects the same side of the body where as a contralateral
reflex effects the opposite side of the body. Like when you step on a tack and have to
balance on the opposite leg when your injured leg pulls back.
22. What is the difference between a sulcus and a fissure?
A sulcus is a depression in the cerebrum where as a fissure are deeper grooves that
Indicate the separate of lobes of the brain.
23. List the 4 major regions of the brain.
Cerebrum, Cerebellum, Diencephalon(thalamus, hypothalamus, and pituitary), and Brain
Stem(mesencephalon, pons, and medulla oblongata)
24.Describe the 3 protection mechanisms of the brain.
Cranium
Cerebrospinal Fluid
Meninges
25.What is a ventricle and where would you find them in the brain?
Chambers formed during brain development (2 lateral ventricles in corpus collusum, 3 rd
ventricle between hemispheres, and 4th ventricle between cerebrum and cerebellum)
26.What is the blood brain barrier and why is it important?
The Blood-brain barrier (BBB) is composed of a network of vessels that form a structural
and chemical barrier between the brain and systemic circulation. Limited BBB permeability
also protects the brain from exposure to molecules that are harmless to peripheral organs but
toxic to neurons in the brain.
27.List the functions of the following (you also need to know locations)
a. Medulla Oblongata- brain stem relays sensory info to the thalamus regulates heart
rate and force of contraction, links the brain with the spinal cord, and sets
respiration rate.
b. Pons- midbrain, relays sensory information and issues somatic motor commands,
relays sensory info to the cerebellum, adjusts activities of respiratory rhythmicity
c. Cerebellum- coordination and balance, posterior/inferior to cerebrum
d. Mesencephalon-integrates visual information and reflex responses to visual
stimuli, subconscious control of upper limbs
e. Diencephalon
i. Thalamus-relays sensory information to the hypothalamus, filters sensory
info going to the hypothalamus
ii. Hypothalamus-thirst, hunger, body temperature, circadian rhythm
f. Limbic System (functional grouping)- establishes emotional states, links conscious
and unconscious functions of the brain stem, long term memories, behavior
g. Corpus Callosum- communication between hemispheres
h. Frontal Lobe-voluntary control of skeletal muscles
i. Parietal Lobe-touch, pressure, pain, vibration, taste, and temperature
j. Temporal Lobe-conscious perception of auditory and olfactory stimuli
k. Occipital Lobe-perception of visual stimuli
l. Hippocampus-storage and retrieval of new long term memories
m. Pituitary gland- master control gland
n. Cerebral Cortex-conscious thought and intellectual function
28.What is Cerebrospinal Fluid? Where is it formed? Where is it found? And how is it
circulated?
Fluid that surrounds the nerve chord and brain and helps protect it. It is formed in the
choroid plexus of the lateral ventricles. It is stored in the ventricles of the brain and it is
circulated in the nerve chord and brain and reabsorbed by venous circulation at the
arachnoid villi.
29.List the 12 pairs of cranial nerves and what they innervate.
30.Give the functions of the following Motor and Sensory areas of the cerebral cortex
a. Primary motor cortex-voluntary movement
b. Primary sensory cortex-receptors for touch, pressure, vibration, taste, and
temperature
c. Association areas-regions of the brain that interpret data and send out a motor
response
d. General Interpretive Areas-integrates sensory information with visual or auditory
memories (Wernicke’s Area)
e. Speech center- Broca’s Area regulates the pattern of breathing and vocalization
needed for speech
f. Prefrontal Cortex-coordinates info relayed from the association areas of the entire
cortex and helps to make predictions.