muscle physiology - action potentials to muscle contractions

Where does the message for muscle contraction come from

motor neurons at the neuromuscular junction

motor neurons release what, that binds to chemically grated sodium channels

acetylcholine (ACh)

what happens ACh binds to chemically grated sodium channels

sodium enters the muscle cell

where does an action potential travel across

the sarcolemma

how does an actional potential travel across the sarcolemma

using voltage grated sodium channels

what do action potentials rely on

the open and closing of voltage grated channel

what is an action potential

a change in membrane charges(positive or negative) that move across the membrane

what causes the membrane to depolarize

when the membrane charge goes up and voltage grated sodium channels open

what helps the membrane to repolarize (bring back to normal)

voltage grated potassium channels, allows potassium to flow out of the cell

how is calcium released

-after sodium depolarized the cell membrane

-allowing the action potential to enter the sarcolemma and travel down the t-tubules

-voltage sensitive proteins press on calcium release channels

-calcium is released from the sarcoplasmic reticulum

what are voltage sensitive proteins

t - tubules

what happens when calcium is released

it attaches to troponin

what happens to calcium during muscle relaxation

Calcium is pumped back into the sarcoplasmic reticulum

-this process requires ATP