Neuro 3050 -Block 2-Final Exam and All
Correct Answers 2026 Updated.
Objectives regarding Internal/External Relationships of the brainstem or how to look at cross
sections of the brain
1) Where possible, correlate external BLANK on the gross brain with underlying BLANK or
BLANK tracts as described in this presentation
2) For each region of the brainstem, learn the location and relationships of BLANK as listed
3) Relate the relative location of cranial nerve nuclei with their functional components. For
example, nuclei that contain general somatic efferent neurons are located BLANK to the midline
whereas nuclei that receive general or special sensory information are located BLANK
4)The medulla, pons and midbrain have distinct appearances when viewed in cross sections.
Learn to identify different levels of the brainstem based on their cross sectional characteristics -
Answer 1) Protuberances, nuclei, fiber
2) nuclei
3) Immediately adjacent, laterally
Brainstem "functions"
1) Contain nuclei...
2) Integrative- Receive..
3) Conduit- BLANK and BLANK tracts - Answer 1) Related to cranial nerve function (Any nuclei
related to the cranial nerves are in the brainstem)
2) Ascending (sensation) and descending (movement) input; serve as relay
3) Ascending and descending
Many, but not all, internal structures (i.e nuclei, tracts) may be correlated with BLANK on the
surface of the brain. Without some type of BLANK, we wouldn't be able to distinguish anything
Images we look at are processed with BLANK stain, so: fiber tracts/bundles of axons will be
stained BLANK. Nuclei will be BLANK in color - Answer Bumps
Stain
Myelin
Black/dark blue
lighter
If you see a structure with lots of= dark blue/purple on it, those areas likely have a lot of fiber
tracts (lots of myelin)
,What is the obex? - Answer The distal, pointed end of 4th ventricle. Landmark for dividing
medulla into caudal and rostral portion.
BLANK-"closed medulla"- BLANK to obex
BLANK-"open medulla"- BLANK surface open to BLANK ventricle - Answer Caudally, Caudal (At
this point, the tissue has come together, we don't see 4th ventricle)
Rostrally, Dorsal
-Superior part of 4th ventricle is associated with the pons and the inferior part is associated
with rostral part of medulla
What is the space between cerebral peduncles (the two stalks really seen on dorsal surface of
brainstem that connect brainstem/specifically midbrain to the brain) called? - Answer
Interpeduncular fossa
Nuclei and/or tracts at the pontomedullary junction - Answer Cochlear nuclei
Spinal trigeminal tract and nucleus
Vestibular nuclei
Nuclei and/or tracts at the rostral medulla - Answer Dorsal motor nucleus X
Hypoglossal nucleus
Inferior olivary nucleus
Nucleus ambiguous
Solitary tract and its nucleus
Spinal trigeminal tract and nucleus
Vestibular nuclei
Nuclei and/or tracts right below rostral medulla and right above caudal medulla (at Obex) -
Answer Spinal trigeminal tract and nucleus
Nuclei and/or tracts at the caudal medulla - Answer Nuclei gracilis and cuneatus --> ML
Spinal trigeminal tract and nucleus pyramid
Nuclei and/or tracts at the spinomedullary junction - Answer Nucleus Gracilis
Pyramidal decussation
Spinal trigeminal tract and nucleus
,What does the anterior median fissure look like on a cross section; slice through the pyramid,
rostral to the pyramidal decussation (Dorsal side is top, ventral is bottom)?
Where is the inferior olive located? - Answer Ant. Median Fissure looks like decently wide slit
on ventral/bottom side of cross section
Lateral to the slit are very darkly stained areas, these are the pyramidal axons- axons going from
motor cortex to spinal cord. Elevations are due to these axon fibers.)
The Inferior olive appears white on the cross section (indicating cell bodies) and it is above the
pyramidal axons
Pyramidal axons - Answer Axons going from motor cortex to spinal cord
What do you notice when looking at the cross section through the pyramidal decussation (the
spino-medullary junction) - Answer -The anterior median fissure slit is appears as just a little
notch as opposed to the longer/wider slit seen when cut through pyramid (Mostly the entire
cross looks like a complete circle. Very round, looks like still in the spinal cord but not quite.
Transitioning from spinal cord to medulla)
-Less white parts (cell bodies) near inferior olive, more stained parts (myelinated fibers) visible.
This is because at the pyramidal decussation, the axons cross over and move from ventral to
dorsal
This is the official transition from spinal cord to brainstem (spino-medullary junction)
Spinal nucleus of V is visible (dorsal part, lateral white circles)
What and where are the three tubercles on the dorsal medulla? - Answer Gracile tubercle-
most medial, looks like a dancer with their legs close together
Cuneate tubercle- Highest tubercle of dorsal medulla (in the middle of other two)
Trigeminal tubercle- Lowest and most lateral tubercle
The dorsal funiculus (Dorsal columns) are lateral/bilateral? What size diameter processes of
dorsal root ganglia neurons (large or small?) - Answer Bilateral (on both sides)
Large (Heavily Myelinated)
Dorsal funiculus in the spinal cord continues to BLANK and maintain this position in the caudal
medulla.
There are two fasciculi present: BLANK and BLANK
, Carry BLANK information from DRG neurons to medulla - Answer -Ascend
-Fasciculus Gracilis (medial)-Touch information from lower limb (relates to Gracile tubercle)
-Fasciculus Cuneatus (lateral)- touch information from upper limb
Sensory
Very important, carrying touch and proprioception info from body
Fasciculus Gracilis - Answer Medial-touch and proprioceptive information from lower limb
(relates to Gracile tubercle)
Carries information from body areas innervated by spinal segments BELOW T6 (i.e lower trunk
and lower limb)
Fasciculus Cuneatus - Answer Lateral-Touch and proprioceptive information from upper limb
(relates to Cuneate tubercle)
Carries information from body areas innervated by spinal segments above T6 (Upper trunk,
Upper limb, neck)
Regarding the Dorsal column of the spinal cord, input from T6-S5 (lower limb) forms BLANK -
Answer Fasciculus Gracilis (Latin for slender)
Regarding the dorsal column of the spinal cord, input from C1-T5 (upper limb) forms BLANK -
Answer Fasciculus Cuneatus (Latin for Wedge) (these are more lateral than FC, which is
medial. Makes sense as the Gracile tubercle is very medial/slender)
As axons enter from the upper limb to form the fasciculus cuneatus, those present in fasciculus
gracilis from the lower limb are shifted BLANK - Answer Medially (pushed in)
BLANK and BLANK relay fine touch, proprioception, etc. from the body. BLANK relays pain and
temperature from the face - Answer Nucleus gracilis and nucleus cuneatus
SP V (spinal nucleus and tract of cranial nerve V)
Structurally related, functionally VERY DIFFERENT
T or F: the Nucleus gracilis, nucleus cuneatus, trigeminal cuneatus, and SP V can be seen from a
cross section straight through the pyramidal decussation - Answer All true except the
trigeminal cuneatus is not a thing so not that
Correct Answers 2026 Updated.
Objectives regarding Internal/External Relationships of the brainstem or how to look at cross
sections of the brain
1) Where possible, correlate external BLANK on the gross brain with underlying BLANK or
BLANK tracts as described in this presentation
2) For each region of the brainstem, learn the location and relationships of BLANK as listed
3) Relate the relative location of cranial nerve nuclei with their functional components. For
example, nuclei that contain general somatic efferent neurons are located BLANK to the midline
whereas nuclei that receive general or special sensory information are located BLANK
4)The medulla, pons and midbrain have distinct appearances when viewed in cross sections.
Learn to identify different levels of the brainstem based on their cross sectional characteristics -
Answer 1) Protuberances, nuclei, fiber
2) nuclei
3) Immediately adjacent, laterally
Brainstem "functions"
1) Contain nuclei...
2) Integrative- Receive..
3) Conduit- BLANK and BLANK tracts - Answer 1) Related to cranial nerve function (Any nuclei
related to the cranial nerves are in the brainstem)
2) Ascending (sensation) and descending (movement) input; serve as relay
3) Ascending and descending
Many, but not all, internal structures (i.e nuclei, tracts) may be correlated with BLANK on the
surface of the brain. Without some type of BLANK, we wouldn't be able to distinguish anything
Images we look at are processed with BLANK stain, so: fiber tracts/bundles of axons will be
stained BLANK. Nuclei will be BLANK in color - Answer Bumps
Stain
Myelin
Black/dark blue
lighter
If you see a structure with lots of= dark blue/purple on it, those areas likely have a lot of fiber
tracts (lots of myelin)
,What is the obex? - Answer The distal, pointed end of 4th ventricle. Landmark for dividing
medulla into caudal and rostral portion.
BLANK-"closed medulla"- BLANK to obex
BLANK-"open medulla"- BLANK surface open to BLANK ventricle - Answer Caudally, Caudal (At
this point, the tissue has come together, we don't see 4th ventricle)
Rostrally, Dorsal
-Superior part of 4th ventricle is associated with the pons and the inferior part is associated
with rostral part of medulla
What is the space between cerebral peduncles (the two stalks really seen on dorsal surface of
brainstem that connect brainstem/specifically midbrain to the brain) called? - Answer
Interpeduncular fossa
Nuclei and/or tracts at the pontomedullary junction - Answer Cochlear nuclei
Spinal trigeminal tract and nucleus
Vestibular nuclei
Nuclei and/or tracts at the rostral medulla - Answer Dorsal motor nucleus X
Hypoglossal nucleus
Inferior olivary nucleus
Nucleus ambiguous
Solitary tract and its nucleus
Spinal trigeminal tract and nucleus
Vestibular nuclei
Nuclei and/or tracts right below rostral medulla and right above caudal medulla (at Obex) -
Answer Spinal trigeminal tract and nucleus
Nuclei and/or tracts at the caudal medulla - Answer Nuclei gracilis and cuneatus --> ML
Spinal trigeminal tract and nucleus pyramid
Nuclei and/or tracts at the spinomedullary junction - Answer Nucleus Gracilis
Pyramidal decussation
Spinal trigeminal tract and nucleus
,What does the anterior median fissure look like on a cross section; slice through the pyramid,
rostral to the pyramidal decussation (Dorsal side is top, ventral is bottom)?
Where is the inferior olive located? - Answer Ant. Median Fissure looks like decently wide slit
on ventral/bottom side of cross section
Lateral to the slit are very darkly stained areas, these are the pyramidal axons- axons going from
motor cortex to spinal cord. Elevations are due to these axon fibers.)
The Inferior olive appears white on the cross section (indicating cell bodies) and it is above the
pyramidal axons
Pyramidal axons - Answer Axons going from motor cortex to spinal cord
What do you notice when looking at the cross section through the pyramidal decussation (the
spino-medullary junction) - Answer -The anterior median fissure slit is appears as just a little
notch as opposed to the longer/wider slit seen when cut through pyramid (Mostly the entire
cross looks like a complete circle. Very round, looks like still in the spinal cord but not quite.
Transitioning from spinal cord to medulla)
-Less white parts (cell bodies) near inferior olive, more stained parts (myelinated fibers) visible.
This is because at the pyramidal decussation, the axons cross over and move from ventral to
dorsal
This is the official transition from spinal cord to brainstem (spino-medullary junction)
Spinal nucleus of V is visible (dorsal part, lateral white circles)
What and where are the three tubercles on the dorsal medulla? - Answer Gracile tubercle-
most medial, looks like a dancer with their legs close together
Cuneate tubercle- Highest tubercle of dorsal medulla (in the middle of other two)
Trigeminal tubercle- Lowest and most lateral tubercle
The dorsal funiculus (Dorsal columns) are lateral/bilateral? What size diameter processes of
dorsal root ganglia neurons (large or small?) - Answer Bilateral (on both sides)
Large (Heavily Myelinated)
Dorsal funiculus in the spinal cord continues to BLANK and maintain this position in the caudal
medulla.
There are two fasciculi present: BLANK and BLANK
, Carry BLANK information from DRG neurons to medulla - Answer -Ascend
-Fasciculus Gracilis (medial)-Touch information from lower limb (relates to Gracile tubercle)
-Fasciculus Cuneatus (lateral)- touch information from upper limb
Sensory
Very important, carrying touch and proprioception info from body
Fasciculus Gracilis - Answer Medial-touch and proprioceptive information from lower limb
(relates to Gracile tubercle)
Carries information from body areas innervated by spinal segments BELOW T6 (i.e lower trunk
and lower limb)
Fasciculus Cuneatus - Answer Lateral-Touch and proprioceptive information from upper limb
(relates to Cuneate tubercle)
Carries information from body areas innervated by spinal segments above T6 (Upper trunk,
Upper limb, neck)
Regarding the Dorsal column of the spinal cord, input from T6-S5 (lower limb) forms BLANK -
Answer Fasciculus Gracilis (Latin for slender)
Regarding the dorsal column of the spinal cord, input from C1-T5 (upper limb) forms BLANK -
Answer Fasciculus Cuneatus (Latin for Wedge) (these are more lateral than FC, which is
medial. Makes sense as the Gracile tubercle is very medial/slender)
As axons enter from the upper limb to form the fasciculus cuneatus, those present in fasciculus
gracilis from the lower limb are shifted BLANK - Answer Medially (pushed in)
BLANK and BLANK relay fine touch, proprioception, etc. from the body. BLANK relays pain and
temperature from the face - Answer Nucleus gracilis and nucleus cuneatus
SP V (spinal nucleus and tract of cranial nerve V)
Structurally related, functionally VERY DIFFERENT
T or F: the Nucleus gracilis, nucleus cuneatus, trigeminal cuneatus, and SP V can be seen from a
cross section straight through the pyramidal decussation - Answer All true except the
trigeminal cuneatus is not a thing so not that
