ANP muscle physiology

myofilaments

contractile proteins

sarcomere

repeating units of contractile proteins that creates striations

Z disc

anchor for thin filament

M line

holds myosin in place

what does the activation of a neuron cause

all muscle fibers of motor unit to contract

neuromuscular junction

connection between motor neuron and muscle fiber

excitation of muscle fiber

A nerve signal triggers an electrical signal to spread across a muscle fiber.

cross bridge

connection between actin and myosin

what happens when tropomyosin blocks myosin

no contraction

cross bridge cyclin in the contraction phase

myosin grabs actin, pulls it, lets it go, then resets

what happens in the sliding filament mechanism

myosin heads pull thin filament toward M line

what happens when thin and thick filaments slide over each other

muscle shortens and the filament length stays the same

what is required to break the cross bridge

ATP

length-tension relationship

Muscle tension depends on how much the filaments overlap at rest.

temporal summation

as stimulus frequency increases, more tension is produced in the muscle fiber

motor unit recruitment

increased muscle tension by activating motor units

concentric contraction

Muscle shortens as tension overcomes the load.

eccentric contraction

Muscle lengthens while producing tension.