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MHD2 Neuro > Motor Systems > Flashcards

Flashcards in Motor Systems Deck (22):
1

When we speak of an upper motor neuron legion, we usually mean a problem with which tract?

Lateral CST

2

Lower motor neurons

Neurons in spinal cord/ brainstem which innervate skeletal muscle

Located in the ventral/anterior horns of the gray mater

3

Organization of lower motor neurons based on innervation

Medial- innervate axial muscles

Lateral- distal muscles

Neurons for extensors are located ventrally

Flexors are located dorsally

4

Motor Units associated with LMN's

S-Units: Slow, for things you do all day long (Red muscle fibers)

FF-units- Fast and fatigable (White muscle fibers)

FR-units- Fast and Resistant to fatigue (White muscle fibers)

5

The ventral horn gets ______ as they're more muscles to innervate

Fatter

6

As you go from S to FF, the anterior horn cell becomes...

Bigger and the amount of force which can be generated becomes larger.

7

Main descending pathway of interest for motor activity

Corticospinal tract (lateral)- all excitatory

8

Basic characteristics of the CST

CORTICALSPINAL TRACT

-There are many non-motor fibers which run through this tract-- sensorimotor integration

-As a result, it has multiple origins

-Only 50% of their fibers come from motor cortex

9

Betz cells

Concentrated in CST and have some control of hand and leg movement-- likely have a large role in walking.

10

Most of the anterior spinal tract descends in the...

Posterior limb of the internal capsule

11

Corticobulbar tract fibers are located where?

Genu of internal capsule

12

Legion in the posterior limb if internal capsule mostly affect what?

Those fibers going to body or limbs on OPPOSITE side of the body.

13

Corticalspinal tract from the pyramids become...

Lateral corticospinal tract

14

Corticospinal tract is generally responsible for...

Fine motor movements of our hand

15

The layers which control motor function ultimately...

Drive lower motor neurons

16

Primary motor cortex

Location where the motor fibers are concentrated-- NOT where learning occurs.

17

Lesion of anterior horn cell will give...

Lower motor neuron syndrome.

Weakness, twitches, atrophy of muscles

18

Legion of upper motor neurons wills give

Upper motor neural syndrome

Often affiliated with a stroke
Causes spasticity and some atrophy (but no twitches and minimal weakness)

19

Issue in cerebellum, association cortex or basal ganglia would cause...

Motor problem but no weakness

20

Oculomotor, trochlear and abducens nuclei receive what type of innervation from corticobulbar neurons?

NO DIRECT INNERVATION

They're controlled by other collections of neurons in the brainstem

21

Cranial nerve nuclei associated with upper motor neurons

XII, V (mostly to opposite side)

VII (some bilateral, some opposite)

IX, X (bilateral)

22

Cranial nerve VII and its crossing over pattern

Cut of VII will cause facial paralysis on one side-- Bell's palsy

Stroke in cerebrum--- Upper face would be spared on both sides. Opposite lower face would be paralyzed.