Neuromuscular Fundamentals

Chapter 2 Exam 1

muscles provide:

protection, joint stability, postural support, thermoregulation

muscles are named based on

appearance, location, function

excitability

ability of muscle to respond to chemical/electrical/mechanical stimuli

contractility

ability of muscle to contract and develop tension against resistance

extensibility

ability to be stretched beyond resting length

elasticity

ability of muscle to return to its original shape after being stretched

fascia

sheet or band of fibrous connective tissue that separates or binds together muscle groups, organs, and other soft tissue structures

concentric contraction

muscle shortens under tension

eccentric contraction

muscle lengths under tension

isometric contraction

tension develops in muscle with no change in joint angle

stabilizer/fixator

surrounds joint and contracts to stabilize the area. enables another limg segment to exert force and move

synergistic

help another muscle to facilitate the same motion

neutralizer

counteracts the action of another muscle to prevent undesired movement

force couples

two muscles contract to create a force that pulls in different directions on an object that creates rotation around an axis

CNS

the gateway of movement

cerebral cortex

highest level of control

basal ganglia

posture, learned movements, equilibrium

cerebellum

sensory impulses, biofeedback

brainstem

arousal and waking state

spinal cord

pathway between CNS and PNS, most specific control, reflexes

divisions of PNS

sensory and motor

dermatome

defined area of skin supplied by a specific spinal nerve

myotome

muscle/group of muscles supplied by a specific spinal nerve

all or none principle

all muscle fibers in a unit will either fire maximally or not at all

muscle length/tension relationship

max ability of a muslce to develop tension and produce force varies depending on the length of the muscle during contraction

optimal degree of stretch for force generation

100-130% of resting length

reciprocal inhibition

antagonist muscles must relax to allow agonist muscles to contract

angle of pull

the angle between the line of pull of muscle and the bone on which that muscle inserts

rotary component

component of muscular force that acts perpendicular to long axis of bone/lever

nonrotary component

stabilizing OR dislocating component depending on if the angle of pull is greater or less than 90 degrees

angle of pull less than 90 degrees

the force is STABILIZING, directs the bone towards joint axis

angle of pull greater than 90 degrees

the force is DISLOCATING, directs the bone away from joint axis

uniarticular

muscles cross and act directly on the joint they cross

biarticular

muscles cross and act on two different joints

multiarticular

muscles act on 3+ joints due to line of pull btwn origin and insertion crossing multiple points

active insufficiency

when the muscle becomes shortened to the point it cannot generate anymore tension

passive insufficiency

the opposing muslce becomes stretched the point it can no longer length and allow movement