A&P 1 Aranda Exam 3 (UTA) question
and answer
Absolute Refractory Period - correct answer ✅period
associated with the opening of the Na+ channels until
they begin to reset to their original resting state. (Neuron
can NOT respond to another stimulus)
relative refractory period - correct answer ✅follows the
absolute refractory period, most Na+ channels have
returned to their resting state, some K+ channels are still
open, and repolarization is occurring. (Requires
exceptionally strong stimulus to open channels)
A neuron will not respond to a second stimulus of equal
strength to the first stimulus to which it has already
responded because - correct answer ✅because the
neuron is in the relative refractory period.
Group A fibers - correct answer ✅Largest diameter, are
mostly somatic and sensory fibers serving the skin,
skeletal muscles, and joints. Thicc myelin sheaths and
conduct at speeds up to 150 m/s
Group B Fibers - correct answer ✅Intermediate
diameter, lightly myelinated fibers
Transmit at 15 m/s
,A&P 1 Aranda Exam 3 (UTA) question
and answer
Group C Fibers - correct answer ✅Smallest diameter,
unmyelinated ANS fibers
Transmit at 1 m/s
Excessive potassium efflux as a result of relatively slower
closure of the potassium gates corresponds to what part
of an action potential curve? - correct answer ✅The
hyperpolarization phase of an action potential
Which of the following could cause a graded
depolarization?
A. K+ leaving the cell through leakage (nongated)
channels
B. Na+ entering the cell through chemically gated
channels
C. K+ leaving the cell through voltage-gated channels
D. Na+ entering the cell through voltage-gated channels -
correct answer ✅B. Na+ entering the cell through
chemically gated channels
, A&P 1 Aranda Exam 3 (UTA) question
and answer
FEEDBACK: Depolarizing graded potentials are small
deviations in voltage across the membrane that make the
membrane potential more negative. The diffusion of Na+
into the cell through chemically gated channels would
make the inside of the cell less negative. In other words,
the influx of Na+ causes a depolarizing graded potential.
The sodium-potassium ion pump will __________. - correct
answer ✅pump three sodium (Na+) ions out of the cell
for every two ions of potassium (K+) it brings into the cell
(3 Na+ in, 2 K+ out)
How would an increased extracellular K+ concentration
affect K+ diffusion at leakage (nongated) channels and
the membrane potential? - correct answer ✅A
decrease in the electrochemical gradient would reduce
K+ leak so cells would be less negative (more
depolarized).
FEEDBACK: Potassium ions normally diffuse out of the cell
along their concentration gradient from higher
intracellular concentration to lower extracellular
concentration. K+ flowing out of the cell causes the cell
to become more negative inside. If extracellular K+ is
increased, the concentration gradient across the
membrane is decreased and therefore K+ is less likely to
and answer
Absolute Refractory Period - correct answer ✅period
associated with the opening of the Na+ channels until
they begin to reset to their original resting state. (Neuron
can NOT respond to another stimulus)
relative refractory period - correct answer ✅follows the
absolute refractory period, most Na+ channels have
returned to their resting state, some K+ channels are still
open, and repolarization is occurring. (Requires
exceptionally strong stimulus to open channels)
A neuron will not respond to a second stimulus of equal
strength to the first stimulus to which it has already
responded because - correct answer ✅because the
neuron is in the relative refractory period.
Group A fibers - correct answer ✅Largest diameter, are
mostly somatic and sensory fibers serving the skin,
skeletal muscles, and joints. Thicc myelin sheaths and
conduct at speeds up to 150 m/s
Group B Fibers - correct answer ✅Intermediate
diameter, lightly myelinated fibers
Transmit at 15 m/s
,A&P 1 Aranda Exam 3 (UTA) question
and answer
Group C Fibers - correct answer ✅Smallest diameter,
unmyelinated ANS fibers
Transmit at 1 m/s
Excessive potassium efflux as a result of relatively slower
closure of the potassium gates corresponds to what part
of an action potential curve? - correct answer ✅The
hyperpolarization phase of an action potential
Which of the following could cause a graded
depolarization?
A. K+ leaving the cell through leakage (nongated)
channels
B. Na+ entering the cell through chemically gated
channels
C. K+ leaving the cell through voltage-gated channels
D. Na+ entering the cell through voltage-gated channels -
correct answer ✅B. Na+ entering the cell through
chemically gated channels
, A&P 1 Aranda Exam 3 (UTA) question
and answer
FEEDBACK: Depolarizing graded potentials are small
deviations in voltage across the membrane that make the
membrane potential more negative. The diffusion of Na+
into the cell through chemically gated channels would
make the inside of the cell less negative. In other words,
the influx of Na+ causes a depolarizing graded potential.
The sodium-potassium ion pump will __________. - correct
answer ✅pump three sodium (Na+) ions out of the cell
for every two ions of potassium (K+) it brings into the cell
(3 Na+ in, 2 K+ out)
How would an increased extracellular K+ concentration
affect K+ diffusion at leakage (nongated) channels and
the membrane potential? - correct answer ✅A
decrease in the electrochemical gradient would reduce
K+ leak so cells would be less negative (more
depolarized).
FEEDBACK: Potassium ions normally diffuse out of the cell
along their concentration gradient from higher
intracellular concentration to lower extracellular
concentration. K+ flowing out of the cell causes the cell
to become more negative inside. If extracellular K+ is
increased, the concentration gradient across the
membrane is decreased and therefore K+ is less likely to
