08a: Clinical and Misc Stuff

Question 1

In general, which CN nuclei found in midbrain?

Answer 1

III: Oculomotor, Edinger-Westphal
IV: Trochlear

Question 2

In general, which CN nuclei found in middle pons?

Answer 2

V: Chief sensory and motor

Question 3

In general, which CN nuclei found in lower pons?

Answer 3

VI: Abducens
VII: Facial
VIII: Cochlear and Vestibular

Question 4

In general, which CN nuclei found in medulla?

Answer 4

V: Spinal trigeminal nucleus
IX/X: Nucleus ambiguous
X: Dorsal and ventral motor nuclei of vagus
XII: Hypoglossal nucleus

Question 5

Descending excitatory projections from motor cortices to brainstem via (X) tract and SC via (Y) tract.

Answer 5

X = corticobulbar
Y = corticospinal

Question 6

Lower motor neurons are those that originate from:

Answer 6

Brainstem or SC

Question 7

When lower motor neurons lose inhibitory input from (X), they do what comes naturally, which is to:

Answer 7

X = upper motor neurons

Continuously fire action potentials

Question 8

A lower motor neuron with no inhibitory input will cause muscles to (X) and reflexes to (Y).

Answer 8

X = increase in contractions and tone
Y = be brisk

Question 9

Weakness of muscle is sign of (upper/lower) motor neuron dysfunction.

Answer 9

Either/both

Question 10

Segmental weakness of muscle is indicative of (upper/lower) motor neuron dysfunction.

Answer 10

Lower

Question 11

Spasticity, aka (X), is indicative of (upper/lower) motor neuron dysfunction.

Answer 11

X = increased tone;

Upper

Question 12

Hyporeflexia or areflexia is indicative of (upper/lower) motor neuron dysfunction.

Answer 12

Lower

Question 13

Flaccidity is indicative of (upper/lower) motor neuron dysfunction.

Answer 13

Lower

Question 14

Fasciculations is indicative of (upper/lower) motor neuron dysfunction.

Answer 14

Lower

Question 15

T/F: You’d see muscle atrophy in both upper and lower motor neuron dysfunction.

Answer 15

False - likely not upper

Question 16

As concentration of extracellular sodium decreases, the action potential curve changes in which way(s)? List the factors contributing to this change.

Answer 16

1. E(Na) decreases (lower amplitude)

2. DF(Na) decreases (smaller upward slope/slower depolarization)

Question 17

Ouabain is a specific inhibitor of:

Answer 17

Na/K pump

Question 18

T/F: At the peak of the action potential the driving force on Na+ ions is
0.

Answer 18

False

Question 19

T/F: During the overshoot of the action potential there is a slight excess
of positive charge on the inside of the membrane.

Answer 19

True

Question 20

T/F: At the resting potential, the current due to K+ ions is larger than that due to all other ions combined.

Answer 20

False

Question 21

Around what voltage does relative refractory period begin?

Answer 21

Threshold (-55 mV or so)

Question 22

In hyperkalemic periodic paralysis (HPP), there is an issue in:

Answer 22

Na channel inactivation

Question 23

T/F: At adrenergic nerve endings (varicosities), acetylcholine acts to
increase norepinephrine (NE) release.

Answer 23

False

Question 24

Autonomic nervous system has (nicotinic/muscarinic) ACh receptors.

Answer 24

Both