CH 17 Skeletal Muscle System

X is the basis for all human movement.

Muscle contraction

X pulls on boney levers to cause movement.

Muscle shortening (contraction)

Functions of skeletal muscle

• locomotion

• body posture

• venous return

• thermogenesis

Irritability

ability to receive and respond to stimuli

Extensibility

ability to be lengthened or stretched

Elasticity

ability to return to resting length after being stretched

Contractility

ability to respond to stimuli by shortening

Thick filaments

Myosin

Thin filaments

• actin

• troponin

• tropomyosin

All or none principal

motor neuron is stimulated, all the muscle fibers in that motor unit contract to their fullest extent or they do not contract at all

Muscle fibers

• SR and T tubules

• myofibrils and myofilaments

• sarcomeres

t tubules

sarcoplasmic reticulum

muscle contraction occurs when

actin contains

sarcomeres are separated by

longitudinal muscle classification

fusiform muscle classification

radiate muscle classification

unipennate muscle classification

Bipennate muscle classification

circular muscle classification