Flashcards in 08a: Clinical and Misc Stuff Deck (24)
In general, which CN nuclei found in midbrain?
III: Oculomotor, Edinger-Westphal
In general, which CN nuclei found in middle pons?
V: Chief sensory and motor
In general, which CN nuclei found in lower pons?
VIII: Cochlear and Vestibular
In general, which CN nuclei found in medulla?
V: Spinal trigeminal nucleus
IX/X: Nucleus ambiguous
X: Dorsal and ventral motor nuclei of vagus
XII: Hypoglossal nucleus
Descending excitatory projections from motor cortices to brainstem via (X) tract and SC via (Y) tract.
X = corticobulbar
Y = corticospinal
Lower motor neurons are those that originate from:
Brainstem or SC
When lower motor neurons lose inhibitory input from (X), they do what comes naturally, which is to:
X = upper motor neurons
Continuously fire action potentials
A lower motor neuron with no inhibitory input will cause muscles to (X) and reflexes to (Y).
X = increase in contractions and tone
Y = be brisk
Weakness of muscle is sign of (upper/lower) motor neuron dysfunction.
Segmental weakness of muscle is indicative of (upper/lower) motor neuron dysfunction.
Spasticity, aka (X), is indicative of (upper/lower) motor neuron dysfunction.
X = increased tone;
Hyporeflexia or areflexia is indicative of (upper/lower) motor neuron dysfunction.
Flaccidity is indicative of (upper/lower) motor neuron dysfunction.
Fasciculations is indicative of (upper/lower) motor neuron dysfunction.
T/F: You'd see muscle atrophy in both upper and lower motor neuron dysfunction.
False - likely not upper
As concentration of extracellular sodium decreases, the action potential curve changes in which way(s)? List the factors contributing to this change.
1. E(Na) decreases (lower amplitude)
2. DF(Na) decreases (smaller upward slope/slower depolarization)
Ouabain is a specific inhibitor of:
T/F: At the peak of the action potential the driving force on Na+ ions is
T/F: During the overshoot of the action potential there is a slight excess
of positive charge on the inside of the membrane.
T/F: At the resting potential, the current due to K+ ions is larger than that due to all other ions combined.
Around what voltage does relative refractory period begin?
Threshold (-55 mV or so)
In hyperkalemic periodic paralysis (HPP), there is an issue in:
Na channel inactivation
T/F: At adrenergic nerve endings (varicosities), acetylcholine acts to
increase norepinephrine (NE) release.