NBCE Part 1- Physiology Exam Questions With
Accurate Answers 2025\2026 A+ Grade
Neurophysiology
- accurate answers-Neurophysiology
1. Which type of receptor does the parasympathetic nervous system activate
at an effector organ?
a. alpha-1
b. nicotinic
c. beta
d. muscarinic
- accurate answers-1. d. Acetylcholine is the most common neurotransmitter
released from parasympathetic postganglionic fibers. The parasympathetic
receptors on effectors are muscarinic. Nicotinic receptors are found at the
synapse between preganglionic and postganglionic neurons of the
sympathetic and parasympathetic nervous systems as well as at
neuromuscular junctions. Acetylcholine can have either an excitatory or
inhibitory effect depending on the type of receptor activated.
2. Which of the following must be activated sequentially for action potential
propagation?
a. peripheral membrane proteins
b. ligand-gated channels
c. voltage-gated ion channels
d. leak channels
- accurate answers-2. c. An action potential is a rapid but transient change in
membrane potential. Action potentials require specific sodium and potassium
voltage-gated ion channels that occur at regions of the cell membrane that are
electrically excitable. Threshold is the point at which the voltage-gated
channels will open.
3. What response would result from a subthreshold stimulus to a nerve cell?
a. action potential
b. graded response
c. no response
d. resting membrane potential
- accurate answers-3. b. A graded response is a local subthreshold response.
Receptor (generator) potentials, pacemaker potentials, postsynaptic
,membrane potentials, and end-plate potentials are some examples of graded
potentials.
4. What is generated if a graded potential should reach threshold?
a. receptor potential
b. pacemaker potential
c. IPSP
d. action potential
- accurate answers-4. d. Graded potentials have variable changes in the
magnitude of the potential. Graded potentials decrease in magnitude as they
move along the cell membrane but can function as signals over a very short
distance. If a graded potential reaches threshold, an action potential is
generated.
5. What is the origin of a receptor potential?
a. sensory neurons
b. neurons of the ANS
c. hypothalamic neurons
d. motor cortex neurons
- accurate answers-5. a. Sensory receptors respond to stimuli from
mechanoreceptors, thermoreceptors, nociceptors (pain), chemoreceptors, and
electromagnetic (vision) receptors. A graded potential caused by a stimulus is
called a receptor potential. If the graded potential reaches threshold, then an
action potential is generated and sensory input is transmitted to the spinal
cord and brain.
6. Which of the following describes why an action potential is propagated
without degradation?
a. it is replaced by graded potentials at specific points on the line membrane
b. it is generated at a very high voltage, which overcomes the capable
properties of the cell
c. it is constantly regenerated all along the membrane
d. it is reinforced by injection of a new ion species of similar change every few
millimeters of movement
- accurate answers-6. c. An action potential is a local event. Conduction with
decrement means the signal will die out in 5 mm. Action potentials are
propagated without decrement because an action potential at one location
acts as a stimulus for the production of an action potential at an adjacent
,region of the membrane. "New" action potentials are produced along the
length of the membrane.
7. Which organ receives preganglionic sympathetic fibers:
a. Pancreas
b. medulla of the adrenal gland
c. uterus
d. testis
- accurate answers-7. b. The chromaffin cells of the medulla of the adrenal
gland develop from neural crest cells which arc associated with the
sympathetic portion of the autonomic nervous system. These cells function
like into the sympathetic postganglionic neurons except that they secrete
catecholamines, mainly epinephrine and nor-epinephrine, into the
bloodstream. Thus they receive preganglionie sympathetic fibers.
8. You are sleeping peacefully when your alarm clock awakens you. What part
of your brain is associated with arousal?
a. peritricial plexus
b. sympathetic system
c. parasympathetic system
d. reticular formation
- accurate answers-8. d. The reticular formation is a diffuse network of fibers
running through the midbrain that is responsible for regulating consciousness
and unconsciousness. The peritricial plexus is the collection of nerve endings
around a hair follicle that allows for the sensation of touch when a hair is
touched.
9. A number of significant clinical conditions involve abnormalities of
neurotransmitter release or reception at the myoneural junction. The
neurotransmitter associated with the motor endplate is:
a. Norepinephrine
b. Dopamine
c. Acetylcholine
d. myasthenia gravis
- accurate answers-9. c. Norepinephrine can be a motor neurotransmitter at
myoneural junctions of postganglionic sympathetic neurons, but the term
"motor endplate" is reserved for only skeletal muscles. Dopamine is a
neurotransmitter in the basal ganglia, which is part of the motor system but
nowhere near the myoneural junction. Myasthenia gravis. is a condition of
, impaired neurotransmitter reception at the motor endplate. which is not what
the question asked about.
10. Often, neurologic deficits can affect specific anatomical regions and not the
rest of the body. Such deficits can result from damage to peripheral nerves,
nerve roots, spinal tracts, or brain centers. Which is the tract responsible for
carrying vibration sense to the upper extremity?
a. rubrospinal tract
b. fasciculus cuneatus
c. fasciculus gracilus
d. anterior spinothalamic tract
- accurate answers-10. b. The rubrospinal tract is a motor tract from the
cerebellum. The fasciculus cuneatus carries vibration, proprioception, and
complex touch from the upper extremity and the fasciculus gracilus provides
the same functions for the lower extremity. The anterior spinothalamic tract
carries pain and temperature.
11. Changes in the membrane potential of excitable cells occur as rates of ion
movement across the cell membrane change. Increased permeability to
chloride causes an influx of chloride into cell, which results in which of the
following responses?
a. Repolarization
b. Hyperpolarization
c. Depolarization
d. plateau
- accurate answers-11. b. The influx of chloride as described is typical of the
IPSP (inhibitory postsynaptic potential).
12. There are a number of differences between nerve fibers that can have an
influence on the time required for the neural action potential in the peripheral
nervous system to travel from its site of origin to the next synapse. Which of
these factors has no influence on the time between the initial and secondary
synapse?
a. the nerve fiber is in an afferent pathway rather than an efferent pathway
b. differences in axon diameter
c. myelinated versus nonmyelinated
d. overall fiber length (anatomical length of nerve)
- accurate answers-12. a. While fiber length is not a factor in the velocity of
nerve transmission, it is a factor in the total time required for the signal to get
Accurate Answers 2025\2026 A+ Grade
Neurophysiology
- accurate answers-Neurophysiology
1. Which type of receptor does the parasympathetic nervous system activate
at an effector organ?
a. alpha-1
b. nicotinic
c. beta
d. muscarinic
- accurate answers-1. d. Acetylcholine is the most common neurotransmitter
released from parasympathetic postganglionic fibers. The parasympathetic
receptors on effectors are muscarinic. Nicotinic receptors are found at the
synapse between preganglionic and postganglionic neurons of the
sympathetic and parasympathetic nervous systems as well as at
neuromuscular junctions. Acetylcholine can have either an excitatory or
inhibitory effect depending on the type of receptor activated.
2. Which of the following must be activated sequentially for action potential
propagation?
a. peripheral membrane proteins
b. ligand-gated channels
c. voltage-gated ion channels
d. leak channels
- accurate answers-2. c. An action potential is a rapid but transient change in
membrane potential. Action potentials require specific sodium and potassium
voltage-gated ion channels that occur at regions of the cell membrane that are
electrically excitable. Threshold is the point at which the voltage-gated
channels will open.
3. What response would result from a subthreshold stimulus to a nerve cell?
a. action potential
b. graded response
c. no response
d. resting membrane potential
- accurate answers-3. b. A graded response is a local subthreshold response.
Receptor (generator) potentials, pacemaker potentials, postsynaptic
,membrane potentials, and end-plate potentials are some examples of graded
potentials.
4. What is generated if a graded potential should reach threshold?
a. receptor potential
b. pacemaker potential
c. IPSP
d. action potential
- accurate answers-4. d. Graded potentials have variable changes in the
magnitude of the potential. Graded potentials decrease in magnitude as they
move along the cell membrane but can function as signals over a very short
distance. If a graded potential reaches threshold, an action potential is
generated.
5. What is the origin of a receptor potential?
a. sensory neurons
b. neurons of the ANS
c. hypothalamic neurons
d. motor cortex neurons
- accurate answers-5. a. Sensory receptors respond to stimuli from
mechanoreceptors, thermoreceptors, nociceptors (pain), chemoreceptors, and
electromagnetic (vision) receptors. A graded potential caused by a stimulus is
called a receptor potential. If the graded potential reaches threshold, then an
action potential is generated and sensory input is transmitted to the spinal
cord and brain.
6. Which of the following describes why an action potential is propagated
without degradation?
a. it is replaced by graded potentials at specific points on the line membrane
b. it is generated at a very high voltage, which overcomes the capable
properties of the cell
c. it is constantly regenerated all along the membrane
d. it is reinforced by injection of a new ion species of similar change every few
millimeters of movement
- accurate answers-6. c. An action potential is a local event. Conduction with
decrement means the signal will die out in 5 mm. Action potentials are
propagated without decrement because an action potential at one location
acts as a stimulus for the production of an action potential at an adjacent
,region of the membrane. "New" action potentials are produced along the
length of the membrane.
7. Which organ receives preganglionic sympathetic fibers:
a. Pancreas
b. medulla of the adrenal gland
c. uterus
d. testis
- accurate answers-7. b. The chromaffin cells of the medulla of the adrenal
gland develop from neural crest cells which arc associated with the
sympathetic portion of the autonomic nervous system. These cells function
like into the sympathetic postganglionic neurons except that they secrete
catecholamines, mainly epinephrine and nor-epinephrine, into the
bloodstream. Thus they receive preganglionie sympathetic fibers.
8. You are sleeping peacefully when your alarm clock awakens you. What part
of your brain is associated with arousal?
a. peritricial plexus
b. sympathetic system
c. parasympathetic system
d. reticular formation
- accurate answers-8. d. The reticular formation is a diffuse network of fibers
running through the midbrain that is responsible for regulating consciousness
and unconsciousness. The peritricial plexus is the collection of nerve endings
around a hair follicle that allows for the sensation of touch when a hair is
touched.
9. A number of significant clinical conditions involve abnormalities of
neurotransmitter release or reception at the myoneural junction. The
neurotransmitter associated with the motor endplate is:
a. Norepinephrine
b. Dopamine
c. Acetylcholine
d. myasthenia gravis
- accurate answers-9. c. Norepinephrine can be a motor neurotransmitter at
myoneural junctions of postganglionic sympathetic neurons, but the term
"motor endplate" is reserved for only skeletal muscles. Dopamine is a
neurotransmitter in the basal ganglia, which is part of the motor system but
nowhere near the myoneural junction. Myasthenia gravis. is a condition of
, impaired neurotransmitter reception at the motor endplate. which is not what
the question asked about.
10. Often, neurologic deficits can affect specific anatomical regions and not the
rest of the body. Such deficits can result from damage to peripheral nerves,
nerve roots, spinal tracts, or brain centers. Which is the tract responsible for
carrying vibration sense to the upper extremity?
a. rubrospinal tract
b. fasciculus cuneatus
c. fasciculus gracilus
d. anterior spinothalamic tract
- accurate answers-10. b. The rubrospinal tract is a motor tract from the
cerebellum. The fasciculus cuneatus carries vibration, proprioception, and
complex touch from the upper extremity and the fasciculus gracilus provides
the same functions for the lower extremity. The anterior spinothalamic tract
carries pain and temperature.
11. Changes in the membrane potential of excitable cells occur as rates of ion
movement across the cell membrane change. Increased permeability to
chloride causes an influx of chloride into cell, which results in which of the
following responses?
a. Repolarization
b. Hyperpolarization
c. Depolarization
d. plateau
- accurate answers-11. b. The influx of chloride as described is typical of the
IPSP (inhibitory postsynaptic potential).
12. There are a number of differences between nerve fibers that can have an
influence on the time required for the neural action potential in the peripheral
nervous system to travel from its site of origin to the next synapse. Which of
these factors has no influence on the time between the initial and secondary
synapse?
a. the nerve fiber is in an afferent pathway rather than an efferent pathway
b. differences in axon diameter
c. myelinated versus nonmyelinated
d. overall fiber length (anatomical length of nerve)
- accurate answers-12. a. While fiber length is not a factor in the velocity of
nerve transmission, it is a factor in the total time required for the signal to get
