Exam One - Pons/Mesencephalon

Question 1

What are the 2 regions of the pons?

Answer 1

• tegmentum
• basilar pons

Question 2

where is the basilar pons

Answer 2

• ventral portion

Question 3

What does the basilar pons contain?

Answer 3

-descending tracts: corticospinal, corticobulbar, and corticopontine (motor tracts)
-transversely oriented pontocerebellar tracts
-pontine nuceli

Question 4

What does the tegmentum contain?

Answer 4

• cranial nerve nuclei
• ascending sensory pathways
• reticular formation
• periaqueductal grey matter

Question 5

What is the one CN that crosses?

Answer 5

4

Question 6

rhomboid fossa

Answer 6

floor of the 4th ventricle, named after shape

Question 7

facial colliculus

Answer 7

swelling on the floor of the 4th ventricle, cause by CN 7 looping over CN 6 nucleus

Question 8

vestibular area

Answer 8

overlies the vestibular nuclei
- balance and coordination of eye and head movements

Question 9

sulcus limitans

Answer 9

groove in the floor of the 4th ventricle, separates motor and sensory nuclei

Question 10

gracile tubercle

Answer 10

swelling on the dorsal surface of the medulla formed by the gracile nucleus

Question 11

CN 6

Answer 11

• abducens nerve
• supplies somatic motor fibers to the lateral rectus muscle, which abducts the eye (turns it laterally)

Question 12

CN 7

Answer 12

-facial nerve
0 carries nerve fibers that control facial movement and expression
-also carries fibers involved in taste to the ant 2/3 of the tongue and produces tears
- has small branches involved in moderating sensitivity to noise volume (stapedius muscle)

Question 13

What supplies blood to the pons?

Answer 13

medial to lateral
branches of BA:
-paramedian
-short circumferential
- long cercumferential

Question 14

cranial nerve associated with the pons proper

Answer 14

5

Question 15

cranial nerves associated with the pontomedullary junction

Answer 15

6,7,8

Question 16

if CN5 is damaged

Answer 16

-trigeminal
-ipsilateral alteration of pain, temperature, light touch on the face

Question 17

if CN 6 is damaged

Answer 17

• abducens
• ipsilateral weakness of abduction (lateral movement of eye)

Question 18

if CN 7 is damaged

Answer 18

• facial
  -ipsilateral facial weakness

Question 19

if CN 8 is damaged

Answer 19

• auditory
• ipsilateral deafness

Question 20

The midbrain is the ______ segment of the brainstem

Answer 20

smallest

Question 21

the midbrain is continuous with the pons ________

Answer 21

caudally

Question 22

the midbrain is continuous with the diencephalon ________

Answer 22

rostrally

Question 23

tectum

Answer 23

• “roof” of midbrain
• contains superior and inferior colliculi

Question 24

crus cerebri

Answer 24

huge white masses, form the ventral surface (base) of the midbrain

Question 25

tracts of midbrain

Answer 25

corticopontine
corticobulbar
corticospinal

Question 26

substantia nigra

Answer 26

movement control center, sends dopaminergic fibers to the striatum
damaged in parkinson’s disease

Question 27

tegmentum

Answer 27

core of the brainstem

Question 28

superior colliculus

Answer 28

visual relay center

Question 29

inferior colliculus

Answer 29

auditory relay center

Question 30

______ changes orientation as it moves from the medulla to the VPL of the thalamus

Answer 30

medial lemniscus

Question 31

What artery supplies the midbrain?

Answer 31

basilar

Question 32

What specific branches off the basilar artery supply the midbrain?

Answer 32

• superior cerebellar a (SCA)
• posterior cerebral a (PCA) : also a branch of PCA called quadrigeminal artery (QA)
• posterior communicating a

Question 33

what are the 2 cranial nerves found in the midbrain?

Answer 33

3 and 4

Question 34

if CN3 is damaged

Answer 34

• oculomotor
• impaired adduction, supraduction and infraduction of the ipsilateral eye
• eye is turned out and slightly down

Question 35

if CN 4 is damaged

Answer 35

• trochlear
• contralateral
• the eye is unable to look down when trying to look towards the nose

Question 36

Where do CN 1&2 originate?

Answer 36

cerebrum

Question 37

What are the 3 basic organizational principles for brainstem neurological syndromes?

Answer 37

1 - normally subdivided into medial (motor) or lateral (sensory) syndromes based on blood supply patterns and structures found within these patterns.
2 - unilateral involvement of long ascending/long descending tracts result in contralateral sensory and motor deficits
3 - cranial nuclei and nerve involvement result in ipsilateral motor and sensory deficits (except CN4)