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BSCI 201 Final Exam Study Guide 2024
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lOMoARcPSD|7293922BSCI 201 Final Exam Study Guide
2024
Format:
● 40 multiple-choice questions (2 points each) from mostly the Nervous system - you will put
your answer on scantron (bring pencils) (80 points)
● 40 True/false statement (2 points each) from all information covered - you will put your
answer on scantron (A for True; B for False) (80 points)
● 10 short answer/free response(50 points)
● 15 Matching statements (correct letters will form a sentence, as usual) (30 points)
● Total will be out of 220 points + 20 possible extra credit = up to 240 points can be earned
*************************************************************************************
The Nervous System
1. Why are neurons amitotic?
a. Neurons contain a nucleus and all other cytoplasmic organelles EXCEPT centrioles,
which are needed for cells to divide. Because centrioles function in cell division, the
fact that neurons lack these organelles is consistent with the amitotic nature of the cell.
Do primary brain tumors originate from neurons in the brain or the supporting cells (neuroglial
cells)? Explain your answer
b. Neuroglial cells -neurons are amitotic, they do not have centrioles needed to divide,
hence cannot replicate/proliferate; only supporting cells are capable of doing this,
because they have the capability to proliferate uncontrollably. The other way to have a
brain tumor would then be through metastasis of cancer from another part of the body
but this would be a secondary brain tumor.
2. Which part of a neuron is known as the:
a. biosynthetic center and why?
i. Cell body- all biosynthetic activities occur in the cell body
b. receptive center and why?
i. Dendrites - receive and convey electrical signals towards cell body
c. conducting region and why?
i. Axon-generates and transmits action potentials away from cell body
d. How many axons can each neuron have?
i. Only ONE
e. secretory region and why?
i. Axon terminals - release neurotransmitters into extracellular space
3. Define the following
a. Nissl body- well developed rough ER, involved in metabolic activity and oxygen
supply for neurons
b. Ganglion- cluster of neuron cell bodies in PNS
c. Nucleus- cluster of neuron cell bodies in the CNS
d. Tract- bundle of axons in CNS
e. Nerve- bundle of axons in PNS
f. Neurilemma- outermost nucleated cytoplasmic layer of schwann cells that surrounds
the axon of neurons in the PNS
g. Nodes of Ranvier- spaces between adjacent myelin sheaths (covering each Schwann
cell) that facilitate rapid electric conduction.
h. Endoneurium- connective tissue that covers each axon
, lOMoARcPSD|7293922
i. Perineurium- CT that covers fascicle
j. Epineurium- CT that covers bundle of perineurium covered fascicles
4. Describe the structural organization of a tract or nerve.*NEFPET/NEFPEN
(frOm innermOst → OutermOst)
NeurOn → endOneurium → fascicle → perineurium → epineurium → tract Or nerve
5. Name and describe the function of all 6 types of supporting cells
a. CNS-central nervous system
i. Astrocytes: involved in forming the blood-brain barrier and regulating
brain function, support and repair neurons
ii. Microglia-weak phagocytes, clean cell debris, less than macrophages
iii. Ependymal cells- line ventricles, beat cilia to move cerebrospinal fluid
iv. Oligodendrocytes- myelinate axons in brain + spinal cord
b. PNS-peripheral nervous system
i. Schwann cells-myelinate axons in pns, have neurilemma and divided along
axon by nodes of ranvier
ii. Satellite cells-supporting cells, act as a chemical barrier
c. Which type of supporting cells are involved in the formation of the Blood-Brain-
Barrier (BBB)?
Astrocytes
d. What is the function of the BBB?
Prevent blood and nerves/nerve cells touching (can cause schizophrenia, etc)
Prevents harmful substances from crossing into the vicinity of neurons in brain to
stop unwanted excitation
6. Explain why myelinated axons in the CNS do not regenerate when severed.
They have no regeneration tube as neurilemma is not present and they are amitotic so they cannot
replicate properly, and microglia cells clean up damaged areas poorly ; Presence of the growth
inhibiting proteins prevent overgrowth of the brain and spinal cord confined by the cranium and
vertebral column.
7. Explain why myelinated axons in the PNS can regenerate when severed.
Has regeneration tube formed by the neurilemma from the schwann cell and nuclei to replicate
8. Explain why impulses are conducted faster in a larger myelinated axon than in a
smaller unmyelinated axon.
a. Diameter of axon = larger axons transmit impulses at faster rate than smaller
axons because larger axons have larger diameter
i. Presents with less resistance in impulse transmission
ii. Resistance in smaller axons = higher which impeded/interrupts
impulse transmission
b. Degree of myelination = myelinated axons transmit impulses at faster rate
than unmyelinated axons
i. Myelinated axons use saltatory conduction = action potentials are generated
only at the Nodes of Ranvier
1. SO = impulse jumps from node to node down axon
ii. Unmyelinated axons use continuous conduction = action potentials
developed stepwise across entire axolemma
9. Describe the
a. Resting membrane potential-
i. resting state no movement, more Na+ ions outside and more K+ ions inside;
-70mv
b. depolarization phase of an action potential
, lOMoARcPSD|7293922
i. Na+ influx
ii. -70 to +30mv
c. repolarization phase of an action potential-
i. after AP, K+ efflux
ii. +30 to -70mv
d. hyperpolarization phase-
i. more K+ efflux,
ii. -70 to -90mv
iii. then return to RMP of -70mv
10. What are the absolute refractory period and relative refractory period of an action potential?
a. Absolute Refractory Period: Occurs when the sodium gates are still open
(depolarization phase) and the neuron is unable to initiate a new action potential
b. Relative Refractory Period: When the neuron is undergoing repolarization and
therefore the sodium gates are closed, an exceptionally strong stimulus can cause
initiation of another action potential
11. How do you tell the difference between a strong stimulus (such as an intense pain) and a
weak stimulus (such as a mild pain) that caused action potential generation?
a. If there are more frequent action potentials (more waves on the graph) that indicates
a strong stimulus. If there are less frequent action potentials (less/fewer waves on the
graph) then that indicates a weaker stimulus.
12. Name and describe the 3 structural classes of neurons-
a. Uni/pseudopolar- A single process extending from the cell body- divided into
peripheral and central processes (conduct impulses toward the CNS)
Bipolar- Two processes attached to the cell body- one dendrite, one axon (found only in
the eye, ear, and olfactory mucosa)
Multipolar- Many processes issued from the cell body- many dendrites, one axon (most
abundant type of neurons in the body)
b. which structural class is most abundant?
i. multipolar
13. Name and describe the 3 functional classes of neurons
a. Sensory (afferent) Neurons- Carry impulses from sensory receptors in skin, internal
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