Lecture 16 - Lower Motor Neurons

Question 1

Keep in mind a Motor Neuron innervates muscle fibers of how many types?

Answer 1

One! (Either Type 1, Type 2A, or Type 2B)

Question 2

Type ____ muscle fibers are Slow twitch.

Type ____ are Fast twitch and Fatigue RESISTANT.

Type ____ are Fast twitch and Fatigable.

Answer 2

Type 1 Type 2a Type 2b

Question 3

Type 1 muscle fibers use _______ metabolism, and thus have many ______. Type 2 muscle fibers use _______, and thus have few ______.

Answer 3

Oxidative Mitochondria Glycolysis Mitochondria

Question 4

Fiber type _____ is characteristic of Reinnervation after neuronal damage.

Answer 4

Fiber Type Grouping (Muscle fiber types of the same kind group together rather than the pre-damaged Mosaic state).

Question 5

Trigeminal Nerve (CN V - Largest CN) innervate muscles of _______ (derived from the first Branchial arch).

Answer 5

Mastication

Question 7

On which side, ipsilateral or contralateral, do you expect to see facial paralysis in Lower Motor Neuron palsy (Bell’s Palsy) vs Upper Motor Neuron palsy?

Answer 7

Lower Motor Neuron (Bell’s) –> Ipsilateral

Upper Motor Neuron –> Contralateral with sparing of Frontalis

Question 8

Cranial Nerve X is the _____ nerve, and it innervates the striated muscles of the _____ and _____, EXCEPT for the ________ muscle, which is innervated by CN IX (Glossopharyngeal).

Keep in mind CN X exit the brainstem with CN IX through the _______ foramen.

Answer 8

Vagus

Pharynx

Larynx

Styloglossal

Jugular foramen

Question 9

CN XI (Spinal Accessory nerve) innervates the ________ and ________ muscles. It is strictly a _______ (ipsilateral or contralateral?) nerve.

Answer 9

Sternocleidomastoid

Trapezius

Contralateral

Question 10

CN XII is the Hypoglossal nerve, a somatic motor nerve that innervates the ______. It is a strictly _______ (ipsilateral or contralateral?) nerve.

Answer 10

Tongue