PNB 2264 Final Cumulative UPDATED Exam Questions and CORRECT Answers
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Course
PNB 2264
Institution
PNB 2264
PNB 2264 Final Cumulative UPDATED
Exam Questions and CORRECT Answers
During contraction of the sarcomere:
A. The size of the I band decreases
B. The size of the A band decreases
C. The size of the H zone increases
D. Both A & B are correct - CORRECT ANSWER- A. The size of the I band decreases
PNB 2264 Final Cumulative UPDATED
Exam Questions and CORRECT Answers
During contraction of the sarcomere:
A. The size of the I band decreases
B. The size of the A band decreases
C. The size of the H zone increases
D. Both A & B are correct - CORRECT ANSWER- ✔✔A. The size of the I band decreases
The concentration of sodium ions inside the cell is 10mM, and the extracellular concentration
is 100mM. The equilibrium potential for sodium under these conditions is +58mV. If the
extracellular concentration of sodium was changed to 500mM, equilibrium potential:
a. Would become more positive
b. Would become more negative
c. Would remain the same
d. Cannot be determined with the information provided - CORRECT ANSWER- ✔✔a.
Would become more positive
The regions of the central nervous system which contain synapses, dendrites, and cell bodies
(soma) are classified as:
a. White matter
b. Gray matter
c. Glia
d. Nodes - CORRECT ANSWER- ✔✔b. Gray matter
All of the following prevent the release of Acetylcholine from Alpha Motor Neurons
EXCEPT:
a. Tetrodotoxin (A Voltage Gated Sodium Channel Inhibitor) Poisoning
b. Guillaine-Barre Syndrome
c. Myasthenia gravis
d. Lambert Eaton Syndrome - CORRECT ANSWER- ✔✔c. Myasthenia gravis
,Adult muscle fibers are created from the fusion of muscle precursor cells called:
a. Myoblasts
b. Satellite Cells
c. Myofibrils
d. Myosomes
e. Sarcosomes - CORRECT ANSWER- ✔✔a. Myoblasts
The action potential is initiated at the __________________ because it contains the highest
concentration of ____________________ channels.
a. Axon; Ligand gated sodium
b. Axon; Voltage gated sodium
c. Axon hillock (initial segment); Ligand gated sodium
d. Axon hillock (initial segment); Voltage gated sodium
e. Dendrites; Ligand gated sodium - CORRECT ANSWER- ✔✔d. Axon hillock (initial
segment); Voltage gated sodium
Excitation-contraction coupling refers to:
a. The sequence of events that lead to the muscle action potential
b. The hydrolysis of ADP on the myosin head that leads to the powerstroke
c. Events that happen in between opening the voltage gated sodium channel and crossbridge
formation
d. All of the above - CORRECT ANSWER- ✔✔c. Events that happen in between opening the
voltage gated sodium channel and crossbridge formation
Which of the following is TRUE about neurons?
a. Neurons expend very little ATP
b. Neurons are mitotic
c. Neurons usually outlive many other cells inside the body.
d. In adults, the CNS contains a fixed amount of neurons for the duration of an individual's
life.
e. All of the above are true - CORRECT ANSWER- ✔✔c. Neurons usually outlive many
other cells inside the body.
, Ion X is negatively charged. Its concentration outside the cell is 200mM, and its
concentration inside the cell is 50mM. The cell is permeable to ion X. The equilibrium
potential for this ion:
a. Would be positive
b. Would be negative
c. May be positive or negative
d. Would be zero - CORRECT ANSWER- ✔✔b. Would be negative
Internodes:
a. Are unmyelinated regions of the axon
b. Contain relatively higher numbers of voltage gated ion channels than other regions of the
axon
c. May be created by Schwann cells
d. Are regions where presynaptic and postsynaptic neurons communicate - CORRECT
ANSWER- ✔✔C. May be created by Schwann cells
Which of the following is not a glial cell of the central nervous system?
a. Astrocytes
b. Ependymal cells
c. Oligodendrocytes
d. Microglia
e. Satellite cells - CORRECT ANSWER- ✔✔e. Satellite cells
During the depolarization phase of the action potential:
a. A positive feedback loop is triggered
b. Local currents inhibit the sodium potassium pump
c. Leaky potassium channels close
d. All of the above - CORRECT ANSWER- ✔✔a. A positive feedback loop is triggered
According to the length tension relationship:
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