Muscle Function (Analysis + Demo)

Question 1

agonists

Answer 1

primary mover, functional muscle group. responsible for specific action at a joint

Question 2

antagonists

Answer 2

oppose or reverse action of prime mover

Question 3

synergists

Answer 3

assist prime mover in its actions

Question 4

how do muscle pairs work together for max efficiency, speed and control?

Answer 4

increase tone in prep for full activation, antagonist prepares to slow down/stop, and muscle pair coordinates ctxn to avoid muscle injury

Question 5

MUAP (motor unit action potential)

Answer 5

depol of all fibers in a motor unit creates MUAP, analysis of these and assessment of baseline electrical signal @ rest = foundation of electromyography. monitored by surface or needle electrode

Question 6

motor unit

Answer 6

axon + all of the muscle fibers it innervates

Question 7

innervation ratio

Answer 7

of muscle fibers innervated by a single axon/motor neuron (fine motor = low, gross motor = high)

Question 8

sensory nerve action potential

Answer 8

onset latency, peak latency

Question 9

compound muscle AP

Answer 9

latency

Question 10

size principle

Answer 10

recruited smaller first, then med then larger. de-recruit in same order

Question 11

nerve conduction studies

Answer 11

test motor, sensory, mixed nerves

Question 12

electromyography tests

Answer 12

tests skeletal muscle fibers. needle type tests type 1 muscle fibers

Question 13

types of contraction

Answer 13

isometric (contracts w/ no movement), concentric (contraction), eccentric (elongation)

Question 14

upper motor neuron syndrome

Answer 14

lesion of upper motor neuron in central nervous system (brain, spinal cord)

Question 15

positive sign for upper motor neuron syndrome

Answer 15

overactivity, hyperreflexia, spasticity

Question 16

negative sign for upper motor neuron syndrome

Answer 16

weakness, underactivity no inherent muscle atropy

Question 17

spasticity

Answer 17

velocity-dependent increase in tonic stretch reflex (muscle tone), hyperexcitability of stretch reflex.

Question 18

botulinum neurotoxin

Answer 18

can be given intra-muscularly to reduce focal muscle overactivity. affects both intrafusal and extrafusal muscle. may affect nociceptor pathways via C and A delta fibers & substance P. can also block salivary and sweat gland. treats dystonia, spasticity, eye, GI/GU, skin and pain

Question 19

Botulinum toxin mech

Answer 19

local, temporary. blocks SNAP 25, no fusing of ACh vesicles, no release of ACh into post-synaptic membrane.