muscle contraction

sliding filament theory

myosin and actin filaments are slide past each other when muscles contract/relax

actin filament

anchored by their + sides to the Z disc

• thin filament

Z disk

dividers between one portion of actin and myosin

contraction

space gets smaller without shortening any filaments

• caused by the myosin heads walking towards the + end of actin

T/F: neuronal signal to muscles stims an action potential which then goes to the sarcoplasmic reticulum and then a voltage gated Ca2+ channel opens

true

troponin

controls skeletal muscle contraction

• when Ca2+ binds to it, this molecule moves the tropomyosin (tropomyosin would otherwise block the interaction of actin with myosin heads)

Na/K pump

• plays key role in membrane transport in animals - active transport

• 3Na+ into cell = coupled with the movement of other molecules across the membrane

• 2K+ out of cell = maintaining proper functioning of the nervous system