PNB 2264 Exam 3 Test Questions and
Already Passed Answers 2026
Updated.
Chemical messengers that cross the synapse bind to _____ channels, which create _______
potentials.
a. Ligand gated; Action
b. Voltage gated; Graded
c. Ligand gated; Graded
d. Voltage gated; Action - Answer c. Ligand gated; Graded
An IPSP could be caused by opening a ________ channel or closing a ________ channel -
Answer potassium; sodium
Place the following events in the order they occur, starting with the depolarization of the axon
hillock: - Answer 1.) Voltage gated sodium channels open in an internode segment
2.) Voltage gated calcium channels in the axon terminal open
3.) Acetylcholine enters the synapse
4.) Sodium enters thru a ligand gated channel
5.) End plate potential develops
6.) Voltage gated sodium channels open on the sarcolemma
7.) Calcium levels in muscle increase
8.) Cross bridges form
During filament sliding, Z discs move towards the M line and:
a. The size of the A bands become smaller
b. The size of the I-bands become larger
c. The size of the H-zones become smaller
d. All of the above - Answer c. The size of the H-zones become smaller
The knee jerk reflex requires ____ synapse(s) to activate quadriceps contraction in response to
quick stretch of that muscle. The synapse(s) is/are found in the __ .
a. One; ventral horn
, b. One; dorsal horn
c. One; dorsal root ganglia
d. Two; ventral horn
e. One; ventral root - Answer a. One; ventral horn
The dorsal root contains _______.
a. A ganglion
b. Sensory axons
c. Motor and sensory axons
d. Both a ganglion and sensory axons
e. All of the above - Answer d. Both a ganglion and sensory axons
____ is required to inhibit the antagonistic knee flexors during the knee jerk reflex
a. Inhibitory transmitter released to the hamstrings
b. Inhibitory transmitter released in the spinal cord
c. Both of the above
d. Neither of the above - Answer b. Inhibitory transmitter released in the spinal cord
The reflex "wired" in this diagram is most accurately represents activation of muscle contraction
(and movement) for the:
a. Knee jerk reflex
b. Flexor withdrawal reflex - Answer b. Flexor withdrawal reflex
white matter - Answer axons
gray matter - Answer cell bodies and (usually) synapses. e.g. cerebral cortex
Tract - Answer Group of axons traveling together in the CNS
nerve - Answer Group of axons traveling together in the PNS - usually both afferent (sensory /
incoming) and efferent (motor / outgoing)
Already Passed Answers 2026
Updated.
Chemical messengers that cross the synapse bind to _____ channels, which create _______
potentials.
a. Ligand gated; Action
b. Voltage gated; Graded
c. Ligand gated; Graded
d. Voltage gated; Action - Answer c. Ligand gated; Graded
An IPSP could be caused by opening a ________ channel or closing a ________ channel -
Answer potassium; sodium
Place the following events in the order they occur, starting with the depolarization of the axon
hillock: - Answer 1.) Voltage gated sodium channels open in an internode segment
2.) Voltage gated calcium channels in the axon terminal open
3.) Acetylcholine enters the synapse
4.) Sodium enters thru a ligand gated channel
5.) End plate potential develops
6.) Voltage gated sodium channels open on the sarcolemma
7.) Calcium levels in muscle increase
8.) Cross bridges form
During filament sliding, Z discs move towards the M line and:
a. The size of the A bands become smaller
b. The size of the I-bands become larger
c. The size of the H-zones become smaller
d. All of the above - Answer c. The size of the H-zones become smaller
The knee jerk reflex requires ____ synapse(s) to activate quadriceps contraction in response to
quick stretch of that muscle. The synapse(s) is/are found in the __ .
a. One; ventral horn
, b. One; dorsal horn
c. One; dorsal root ganglia
d. Two; ventral horn
e. One; ventral root - Answer a. One; ventral horn
The dorsal root contains _______.
a. A ganglion
b. Sensory axons
c. Motor and sensory axons
d. Both a ganglion and sensory axons
e. All of the above - Answer d. Both a ganglion and sensory axons
____ is required to inhibit the antagonistic knee flexors during the knee jerk reflex
a. Inhibitory transmitter released to the hamstrings
b. Inhibitory transmitter released in the spinal cord
c. Both of the above
d. Neither of the above - Answer b. Inhibitory transmitter released in the spinal cord
The reflex "wired" in this diagram is most accurately represents activation of muscle contraction
(and movement) for the:
a. Knee jerk reflex
b. Flexor withdrawal reflex - Answer b. Flexor withdrawal reflex
white matter - Answer axons
gray matter - Answer cell bodies and (usually) synapses. e.g. cerebral cortex
Tract - Answer Group of axons traveling together in the CNS
nerve - Answer Group of axons traveling together in the PNS - usually both afferent (sensory /
incoming) and efferent (motor / outgoing)
