Brain Stem

Question 1

The ____ ____ ____ of the trigeminal is to the face what the ____ ____ ___ in ventral horn are for the body (voluntary control of skeletal muscle.

Answer 1

The main motor nucleus (trigeminal motor nucleus) of the trigeminal is to the ace what the alpha motor neurons in the ventral horn are for the body (voluntary control of skeletal muscle).

Question 2

The ____ ____ ____ of the trigeminal is to the face what the ____ __ ____ is for the body (find touch, vibration, pressure).

Answer 2

The principal sensory nucleus of the trigeminal is to the face what the NG or NC is for the body (fine touch, vibration, pressure).

Question 3

The mesencephalic nucleus of the trigeminal is to the face what the ____ is for the body (proprioception).

Answer 3

DRG

-mesencephalic n. is derived from neural crest cells and innervates proprioceptors on the gums and jaw

Question 4

The spinal nucleus of the trigeminal is to the face what the ____ is for the body (pain and temp).

Answer 4

N. Proprius

-spinal carries pain/temp

Question 5

Jaw Jerk Reflex

-afferent and efferent

Answer 5

• downward tapping of the jaw causes bilateral contraction of the masseter
  afferent: mesencephalic nucleus of the trigeminal (V)
• efferent: main motor nucleus of the trigeminal (V)

Question 6

Corneal Reflex

-afferent and efferent

Answer 6

• afferent: Spinal Nucleus of V

- efferent: Motor Nucleus of VII

Question 7

Pupillary Light Reflex

-afferent and efferent

Answer 7

• afferent: Optic Nerve

- efferent: Parasympathetic division of III (Edinger Westphal Nucleus to Ciliary Ganglion)

Question 8

Gag Reflex

-afferent and efferent

Answer 8

• afferent: glossopharyngeal nerve, 9 (sensory fibers)

- efferent: vagal division of nucleus ambiguous, 10 (nucleus ambiguous)

Question 9

Corticospinal Tract

Answer 9

• upper motor nerve fibers that travel from the cerebral cortex to the spinal cord
• pyramidal tract
• if cut= spastic paralysis
• decussates at the level of the spino-medullary junction (base of medulla) arising from the medullary pyramids

Question 10

Medial Lemniscus

Answer 10

• ascending bundle of myelinated nerve fibers that decussates in the medulla
• composed of axons from nucleus gracilis and nucleus cuneatus
• dorsal column
• if cut= loss of 2 pt discrimination, find touch, proprioception
• decussates: mid-medulla

Question 11

Spinothalamic Tract

Answer 11

• sensory pathway from skin to thalamus
• pain and temp
• anterolateral system
• if cut= loss of pain and temp
• decussates: at level of spinal cord

Question 12

Corticobulbar Tract

Answer 12

-upper motor nerve fibers that travel from the cerebral cortex to the brainstem
-pyramidal tract
-if cut= spastic paralysis
-decussation: medulla
-

Question 13

Colliculi

Answer 13

-located in midbrain

Question 14

Crus Cerebri

Answer 14

• cerebral peduncles

- forms the ventral border of the midbrain and marks the exit point for oculomotor nerve (CN3)

Question 15

Cerebral Aqueduct Location

Answer 15

-midbrain

Question 16

4th Ventricle Location

Answer 16

-pons and rostral (mouth end) medulla

Question 17

Cerebral Peduncle

Answer 17

• input: cerebrum

- output: spinal cord, pons, CN nuclei

Question 18

Spinal Trigeminal Tract & Nucleus

Answer 18

• if cut= loss of pain and temp for head
• descending trigeminal tract
• carry pain and temp info for head

Question 19

Cranial Nerves of Midbrain

Answer 19

3, 4, edinger westphal nucleus

Question 20

Cranial Nerves of Pons

Answer 20

5 (mesncephalic n., primary motor n., main sensory n., spinal.) , 6, 7, 8 (cochlear n. and vestibular n.)

Question 21

Cranial Nerves of Medulla

Answer 21

9 (solitary n.), 10 (solitary n., dorsal motor n. of vagus, ventral motor n of vagus aka n. ambiguous), 11, 12 (hypoglossal n., spinal n. of V)

Question 22

Medial Longitudinal Fasiculus

Answer 22

• coordinates eye movements with head movements

- CN 3, 4, 6, 8

Question 23

Dorsal Motor Nucleus of 10

Answer 23

-preganglionic parasympathetic vagal neurons to heart and thoracic and abdominal viscera

Question 24

Nucleus Ambiguous

Answer 24

• motor vagal neurons to muscles of pharynx, larynx, stylopharyngeus
• CN 9, 10, 11
• brachiomotor nucleus

Question 25

Solitary Nucleus

Answer 25

• vagal
• special sensory (taste) from 7, 9, 10
• visceral sensory info (taste, baroreceptors, gut distention)

Question 26

Paralysis of Half of Face Below Eyebrow

Answer 26

-upper motor neuron lesion

Question 27

Paralysis of Half of Face

Answer 27

• lower motor neuron lesion

- Bell’s Palsy

Question 28

Pupillary Light Reflex

Answer 28

• afferent: optic nerve

- efferent: parasym

Question 29

What structure lies ventral to the rostral part of the 4th ventricle

Answer 29

-basis pontis

Question 30

Combined deficit of which two tracts indicates a medullary lesion?

Answer 30

Pyramidal and MLS (medial lemniscal system) deficits (motor + proprioception) together indicate a medullary lesion because in the medulla these structures are very close to eachother.

Question 31

Combined deficit of which two tracts indicates a midbrain lesion?

Answer 31

• anterolateral system and medial lemniscal system
• spinothalamic (ALS, pain/temp) and MLS deficits indicates a midbrain lesion because these two structures are very close together at this level.