Muscle Function (Analysis + Demo) Flashcards
agonists
primary mover, functional muscle group. responsible for specific action at a joint
antagonists
oppose or reverse action of prime mover
synergists
assist prime mover in its actions
how do muscle pairs work together for max efficiency, speed and control?
increase tone in prep for full activation, antagonist prepares to slow down/stop, and muscle pair coordinates ctxn to avoid muscle injury
MUAP (motor unit action potential)
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
motor unit
axon + all of the muscle fibers it innervates
innervation ratio
of muscle fibers innervated by a single axon/motor neuron (fine motor = low, gross motor = high)
sensory nerve action potential
onset latency, peak latency
compound muscle AP
latency
size principle
recruited smaller first, then med then larger. de-recruit in same order
nerve conduction studies
test motor, sensory, mixed nerves
electromyography tests
tests skeletal muscle fibers. needle type tests type 1 muscle fibers
types of contraction
isometric (contracts w/ no movement), concentric (contraction), eccentric (elongation)
upper motor neuron syndrome
lesion of upper motor neuron in central nervous system (brain, spinal cord)
positive sign for upper motor neuron syndrome
overactivity, hyperreflexia, spasticity
negative sign for upper motor neuron syndrome
weakness, underactivity no inherent muscle atropy
spasticity
velocity-dependent increase in tonic stretch reflex (muscle tone), hyperexcitability of stretch reflex.
botulinum neurotoxin
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
Botulinum toxin mech
local, temporary. blocks SNAP 25, no fusing of ACh vesicles, no release of ACh into post-synaptic membrane.