NURS 5357 NEUROBIOLOGY EXAM 3
ACTUAL TEST PAPER 2026 COMPLETE
QUESTIONS AND VERIFIED SOLUTIONS
GRADED A+
⩥ Mechanoreceptors.
Answer: Large, quick, pseudounipolar sensory neurons that change
physical energy in the form of pressure/stretch/vibration into neural
energy via transduction.
⩥ Dorsal Root Ganglia.
Answer: 1st-order mechanoreceptor cells.
⩥ Mechanoreceptor Pathway.
Answer: 1st-order cells enter SC --> ascend ipsilaterally w/o synapsing
in SC --> ascends in dorsal white matter of SC --> synapses w/ 2nd-
order cells in brainstem --> 2nd-order axons decussate --> synapses w/
3rd-order cells in thalamus --> projects to somatosensory cortex
(postcentral gyrus, sensory homunculus)
⩥ Sensory Homonculus.
Answer: Somatotopic map, topographically faithful representation of
body relationships, size of body structure reflects sensitivity.
,⩥ Pacinian Corpuscle.
Answer: Skin receptor that detects pressure and vibration; produces a
graded receptor/generator potential
⩥ Receptor/Generator Potential.
Answer: When a potential is big enough and the receptor reaches
threshold to generates an action potential (ex. amplitude converted into
action potential frequency by neurites --> signal intensity = frequency =
rate code)
⩥ Nociceptors.
Answer: Free, diffusely projecting nerve endings of small, slow,
myelinated/unmyelinated fibers that transport information regarding
noxious stimuli to the CNS; tissue damage depolarizes directly.
⩥ Nociceptor Pathway.
Answer: 1st-order cells enter SC --> synapses w/ 2nd-order cells in SC
dorsal horn (layers I, II, V) --> 2nd-order cells decussate and project to
brainstem --> synapses w/ 3rd-order cells in thalamus and RF -->
ascends in SC lateral white matter
⩥ Ascending Nociceptor System.
Answer: 1st-order DRG cells project into periphery have axons inserting
into SC dorsal horn --> mechanical damage depolarizes peripheral
,neurite and sends depolarizing signals to DRG cells --> tissue damage
causes release of H, BK, PG, 5HT --> inflammation that causes
tenderness or hyperalgesia --> SP released from sensory nerves causing
platelets to release 5HT and causes Mast cells to release H
⩥ Substance P.
Answer: Pain transmitter peptide located heavily in dorsal horn of SC,
specifically located within areas of C- and A-delta fiber synaptic
termination (ex. PIS caused by spinal SP depletion).
⩥ C-fibers and A-delta Fibers.
Answer: How nociception is carried to the SC; C-fibers are the only
unmyelinated ones, both terminate in superficial aspects of SC dorsal
horn and synapse immediately onto 2nd-order cells conveying pain info;
A-delta terminates more deeply and reflects instant/sharp pain while C-
fibers reflect constant/dull pain
⩥ Gate Control Theory of Pain.
Answer: The substantia gelatinosa integrates pain and non-painful
signals by gating pain processing; large-fiber touch activity closes the
gate while small-fiber pain activity opens it.
⩥ Descending Analgesia System.
, Answer: Electrical stimulation of a number of areas within the brainstem
will render an animal analgesic; PAG targets RVM that includes raphe
nuclei.
⩥ Endorphin.
Answer: Endogenous opiate-like molecule comprised of 31 AAs in
pituitary and brain.
⩥ Enkephalin.
Answer: Comprised of 5 AAs in SC and adrenal gland, co-localizes axo-
synaptically with SP in dorsal horn to produce pain control
presynaptically by inhibiting SP release and cutting off EPSPs to 2nd-
order cells.
⩥ Cornea and lens.
Answer: Refracts and focuses light to form an image.
⩥ Ciliary muscles.
Answer: Adjusts focus by changing shape of the lens.
⩥ Accomodation.
Answer: Process of focusing light to create a sharp image.
⩥ Pupil.
ACTUAL TEST PAPER 2026 COMPLETE
QUESTIONS AND VERIFIED SOLUTIONS
GRADED A+
⩥ Mechanoreceptors.
Answer: Large, quick, pseudounipolar sensory neurons that change
physical energy in the form of pressure/stretch/vibration into neural
energy via transduction.
⩥ Dorsal Root Ganglia.
Answer: 1st-order mechanoreceptor cells.
⩥ Mechanoreceptor Pathway.
Answer: 1st-order cells enter SC --> ascend ipsilaterally w/o synapsing
in SC --> ascends in dorsal white matter of SC --> synapses w/ 2nd-
order cells in brainstem --> 2nd-order axons decussate --> synapses w/
3rd-order cells in thalamus --> projects to somatosensory cortex
(postcentral gyrus, sensory homunculus)
⩥ Sensory Homonculus.
Answer: Somatotopic map, topographically faithful representation of
body relationships, size of body structure reflects sensitivity.
,⩥ Pacinian Corpuscle.
Answer: Skin receptor that detects pressure and vibration; produces a
graded receptor/generator potential
⩥ Receptor/Generator Potential.
Answer: When a potential is big enough and the receptor reaches
threshold to generates an action potential (ex. amplitude converted into
action potential frequency by neurites --> signal intensity = frequency =
rate code)
⩥ Nociceptors.
Answer: Free, diffusely projecting nerve endings of small, slow,
myelinated/unmyelinated fibers that transport information regarding
noxious stimuli to the CNS; tissue damage depolarizes directly.
⩥ Nociceptor Pathway.
Answer: 1st-order cells enter SC --> synapses w/ 2nd-order cells in SC
dorsal horn (layers I, II, V) --> 2nd-order cells decussate and project to
brainstem --> synapses w/ 3rd-order cells in thalamus and RF -->
ascends in SC lateral white matter
⩥ Ascending Nociceptor System.
Answer: 1st-order DRG cells project into periphery have axons inserting
into SC dorsal horn --> mechanical damage depolarizes peripheral
,neurite and sends depolarizing signals to DRG cells --> tissue damage
causes release of H, BK, PG, 5HT --> inflammation that causes
tenderness or hyperalgesia --> SP released from sensory nerves causing
platelets to release 5HT and causes Mast cells to release H
⩥ Substance P.
Answer: Pain transmitter peptide located heavily in dorsal horn of SC,
specifically located within areas of C- and A-delta fiber synaptic
termination (ex. PIS caused by spinal SP depletion).
⩥ C-fibers and A-delta Fibers.
Answer: How nociception is carried to the SC; C-fibers are the only
unmyelinated ones, both terminate in superficial aspects of SC dorsal
horn and synapse immediately onto 2nd-order cells conveying pain info;
A-delta terminates more deeply and reflects instant/sharp pain while C-
fibers reflect constant/dull pain
⩥ Gate Control Theory of Pain.
Answer: The substantia gelatinosa integrates pain and non-painful
signals by gating pain processing; large-fiber touch activity closes the
gate while small-fiber pain activity opens it.
⩥ Descending Analgesia System.
, Answer: Electrical stimulation of a number of areas within the brainstem
will render an animal analgesic; PAG targets RVM that includes raphe
nuclei.
⩥ Endorphin.
Answer: Endogenous opiate-like molecule comprised of 31 AAs in
pituitary and brain.
⩥ Enkephalin.
Answer: Comprised of 5 AAs in SC and adrenal gland, co-localizes axo-
synaptically with SP in dorsal horn to produce pain control
presynaptically by inhibiting SP release and cutting off EPSPs to 2nd-
order cells.
⩥ Cornea and lens.
Answer: Refracts and focuses light to form an image.
⩥ Ciliary muscles.
Answer: Adjusts focus by changing shape of the lens.
⩥ Accomodation.
Answer: Process of focusing light to create a sharp image.
⩥ Pupil.
