Brain Stem: Pons Flashcards Preview

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Flashcards in Brain Stem: Pons Deck (35)
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1
Q

describe the gross anatomy of the pons

A
  1. basilar pons = ventral surface
  2. pontine tegmentum = dorsal surface and floor of 4th ventricle
2
Q

where are ascending sensory tracts generally found in the pons?

A

tegmental area (dorsal surface)

3
Q

where are descending motor tracts generally found in the pons?

A

basilar area (ventral surface)

4
Q

list the fiber tracts that are found in the basilar pons

A
  1. transverse pontine (pontocerebellar)
  2. corticospinal fiber tract
  3. corticobulbar fiber tract
5
Q

what type of info is carried by the transverse pontine (pontocerebellar) tract?

A

relayed afferent signals to cerebellum via middle cerebellar peduncle

6
Q

what type of fibers is the transverse pontine (pontocerebellar) tract made up of?

A

commissural and afferent fibers

7
Q

where are the corticospinal and corticobulbar fiber tracts?

A

run longitudinally through basilar pons

8
Q

what type of info is carried by the corticobulbar tract?

A

somatomotor from precentral gyrus to the head

9
Q

what type of info is carried by the corticospinal tract?

A

somatomotor from precentral gyrus prior to decussation of pyramids heading to the body

10
Q

what nuclei are found in the basilar pons?

A

deep pontine nuclei

11
Q

list the fiber tracts that are found in the tegmental pons

A
  1. facial colliculus
  2. S/M/I cerebellar peduncle
  3. medial lemniscus
  4. medial longitudinal fasciculus
  5. spinothalamic
  6. trigeminothalamic
  7. lateral lemniscus
  8. rubrospinal tract
  9. tectospinal tract
  10. spinal nucleus tract of CN 5
  11. descending limbic and hypothalamic fibers
12
Q

what type of info is carried by the facial colliculus

A

facial nerve CN7 fibers

13
Q

what type of info is carried by the superior cerebellar peduncle?

A

efferent fibers from cerebellum to brain stem and cortex

14
Q

what type of info is carried by the middle cerebellar peduncle?

A

afferent fibers from cortex to cerebellum

15
Q

what type of info is carried by the inferior cerebellar peduncle?

A

afferent fibers from medulla and spinal cord to cerebellum

16
Q

what type of info is carried by the medial lemniscus at the level of the tegmental pons?

A

touch, pressure and proprioception from the entire body ascending to the cortex

17
Q

what type of info is carried by the spinothalamic tract in the tegmental pons?

A

somatosensory (pain and temperature) from body

18
Q

what type of info is carried by the trigeminothalamic tract in the tegmental pons?

A

afferent somatosensory from head to cortex

19
Q

what type of info is carried by the lateral lemniscus in the tegmental pons?

A

auditory relay circuit to inferior colliculus for auditory reflex movement of head

20
Q

what type of info is carried in the rubrospinal tract?

A

efferent motor signals to the arms

21
Q

what type of info is carried by the tectospinal tract?

A

efferent somatomotor signals to muscles of neck and shoulders (head turning reflex)

22
Q

what type of info is carried by the spinal nucleus tract of CN 5?

A

pain and temperature sensation from head

this transitions into the trigeminothalamic tract (in the medulla)

23
Q

what type of info is carried by the descending limbic and hypothalamic fibers of the tegmental pons?

A

info that is carried to autonomic control centers in medulla and spinal cord

24
Q

list the nuclei that are located in the caudal portion of the tegmental pons

A
  1. facial nucleus CN 7
  2. abducens nucleus CN 6
  3. spinal trigeminal nucleus CN 5
  4. superior olivary nucleus (not pictured below)
  5. trapezoid body
  6. M/I vestibular nucleus
  7. superior salvatory nucleus
25
Q

what does the facial nucleus of CN 7 control?

A

muscles of facial expression

26
Q

what does the abducens nucles of CN 6 control?

A

eye muscles (lateral rectus)

27
Q

what do the superior olivary nucleus and trapezoid body do?

A

they are relays in the auditory pathway

28
Q

what does the superior salvatory nucles do?

A

fibers are part of CN7 to lacrima, submandibular, and sublingual salivary glands

29
Q

list the nuclei that are located in the rostral pons

A
  1. main sensory nucleus of CN5
  2. motor nucleus of CN 5
  3. mesencephalic nucleus CN5 (not pictured below)
  4. S/L vestibular nucleus
  5. locus ceruleus
  6. raphe nuclei
30
Q

what is the main sensory nucleus of CN 5?

A

continuation of spinal trigeminal nucleus (light touch from face via trigeminal ganglion synapses here)

31
Q

what does the motor nucleus of CN 5 supply?

A

somatomotor

to muscles of mastication

32
Q

what does the mesencephalic nucleus of CN 5 do?

A

proprioception of jaw (from trigeminal ganglion)

33
Q

what is the locus ceruleus?

A

part of reticular formation (NE)

involved in pain modulation

34
Q

what is the raphe nucleus?

A

part of reticular formation (serotonin)

involved in pain modulation

35
Q

what tracts merge together in the rostral pons to form a single tract to the postcentral gyrus?

A

medial lemniscus

spinothalamic

trigeminothalamic

lateral lemniscus

all merge together into the medial lemniscus