NURS 5357 NEUROBIOLOGY EXAM 4
PRACTICE EVALUATION 2026 QUESTION BANK
FULL SOLUTION SET
◉ 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.
PRACTICE EVALUATION 2026 QUESTION BANK
FULL SOLUTION SET
◉ 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.
