NURS 5357 NEUROBIOLOGY EXAM 3 FINAL
PAPER SOLVED QUESTIONS WITH
ACCURATE ANSWERS STUDY PACK
●● 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
Answer: An opening in the iris that controls how much light enters the
eye.
PAPER SOLVED QUESTIONS WITH
ACCURATE ANSWERS STUDY PACK
●● 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
Answer: An opening in the iris that controls how much light enters the
eye.
