Medulla

Question 1

Hypoglossal Nerve (CN12) @ level of sensory Decussation

Answer 1

1) Involved in Tongue Movement (GSE fiber)
2) LMN for ipsilateral tongue muscles
- receives Bilateral Input from UMN (EXCEPT genioglossal muscle)
3) Genioglossus muscle
- subpopulation of neurons for hypoglossal nucleus
- contraction sticks tongue out
- receives contralateral UMN innervation
- LMN problem w/CN12=deviate towards side of lesion
- UMN problem w/CN12=deviate away from side of lesion

Question 2

Level of Vagus Nerve:

Answer 2

1) Posterior Spinal Cerebellar tracts located in Restiform Body
2) Medial Lemniscus
- Anterior End=LE (Gracilis)
- Posterior End= UE (Cuneate)
3) Pyramidal Tracts-somatotropic arrangement
- Lateral=LE
- Middle=body/trunk
- Medial=UE
4) MLF
5) Hypoglossal nucleus
- moves from medial to more posterior
6) Posterior Longitudinal Fasciculus (PLF)
7) Central Tegmentum Tract
8) Arcuate Nucleus
9) Area Postrema
10) Reticular Formation
11) Inferior Olivary Nucleus

Question 3

Reticular Formation

Answer 3

1) Cardiacs and respiratory function

Question 4

MLF

Answer 4

Medial Longitudinal Fasciculus

-eye movement

Question 5

PLF

Answer 5

Posterior Longitudinal Fasciculus

-connects hypothalamus w/other brainstem nuclei

Question 6

Central Tegmentum tract

Answer 6

1) Connects reticular Formation w/motor cortex

- ascending and descending

Question 7

Arcuate Nucleus

Answer 7

1) Associated with pyramidal tracts
- receives input from corticospinal tracts
- projects to inferior cerebellar peduncle->Cerebellum== Stria Medullaris of 4th ventricle

Question 8

Sulcas Limitans

Answer 8

1) Border that separates the alar and basal plates of developing brainstem

Question 9

Area Postrema

Answer 9

1) AKA vomit center
2) Leaky BBB
3) nausea response to anesthesia

Question 10

Vagus Nerve: 3 nuclei

Answer 10

1) Doral MOtor nucleus of Vagus (DMV)
- parasympathetic (GVE fibers)
- give rise to preganglionic parasympathetic fibers w/vagus
2) Nucleus Ambiguus
- motor function (SVE fibers)
- receives bilateral input from UMN
- LMN innervate skeletal muscle of neck: Phonation(speaking), swallowing, intrinsic muscles of larynx and pharynx
3) Nucleus Solitarius
- Sensory Function–> Visceral Sensory
- receives non conscious sensory from body cavity

Question 11

Level of Vestibulocochlear and Glossopharyngeal

Answer 11

1) Widest part of 4th ventricle
- Roots of : Glossopharyngeal, vestibulocochlear
- ROOTS OF FACIAL NERVE NOT HERE:located closer to medulla/pons junction
- No hypoglossal Nucleus or Vagus nerve
2) Nucleus Propositus
3) Paramedian Pontine Reticular Formation (PPRF)
4) Central Tegmentum
5) CN 9 (glossopharyngeal nerve)
6) Vestibulocochlear Nerve (CN8)
7) Inferior Olivary Nucleus

Question 12

Nucleus Propositus

Answer 12

1) Eye movement

Question 13

PPRF

Answer 13

1) Paramedian Pontine Reticular Formation

- eye movement

Question 14

Glossopharyngeal Nerve: 3 nuclei

Answer 14

1) Nucleus AMbiguus
- LMN
- continuous with vagus nuclei
2) Inferior Salivatory Nucleus
- Continuous w/dorsal motor nucleus of Vagus
- parasympathetic motor function
3) Solitarius Nucleus
- visceral sensory nucleus
- continuous with solitaires nucleus of vagus

Question 15

Vestibulocochlear Nerve (CN8)

Answer 15

1) 2 functions
- vestibular- sense of balance from inner ear
- Cochlear- auditory from inner ear

Question 16

Inferior Olivary Nucleus

Answer 16

1) 3 parts
- principle (or primary)
- Medial accessory
- dorsal accessory

Question 17

Accessory Nerve (CN11) Function

Answer 17

1) innervate Trapezius and sternocleidomastoid muscle
- voluntary skeletal muscle
- not same neurons talking to both
2) Sternocleidomastoid:
- UbMN-Bilteral
- head turn toward side of paralyzed muscle
3) Trapezius
- UMN innervation=mostly contralateral (some bilateral)
- shoulder drop
2) Nuclei located in C1-C5
- enter posterior cranial fossa via foramen magnum
- exit via jugular foramen (w/vagus nerve)
3) LMN
4) GSE fibers)

Question 18

Level of Vagus: Function

Answer 18

1) Nucleus Ambiguus

- innervates Levator Veli Palatini Muscle=holds up arch of posterior roof of mouth