what happens to acetylcholine to stop muscle contraction? What happens to actin when calcium is gone?

What is the difference between a muscle organ, a muscle fiber, a myofibril, and a myofilament?

Hello, may I please get help with this physiology question? An explanation leading to the correct answer would be helpful! Scenario: Your friend Arnold S, who sometimes goes by "Dutch", has started lifting weights because he wants his muscles to get bigger. He's done a little bit of research, and he tells you that weight lifting is increasing the size of myofibrils. Arnie is getting huge, and so you are hesitant to correct him, but you know that what he's saying isn't quite right. The more likely explanation for Arnold's muscles getting bigger is...

What happens inside a muscle to cause that increase in strength to happen over time?

When curare, a neuromuscular poison, is dropped onto an isolated muscle-nerve preparation in a laboratory, the muscle does not contract when the nerve is stimulated, even though neurotransmitter is released from the nerve cell. Why does this happen? How might this action of curare be lethal to an individual who has been poisoned?

What contains troponin, is involuntary and intracellular calcium is necessary in muscle contraction? Multi-unit smooth muscle Unitary smooth muscle O Cardiac muscle fiber Red skeletal muscle fiber White skeletal muscle fiber

Why would a sprinter experience muscle fatigue before a marathon runner would?

What happens when the muscular action potential spreads through transverse (T) tubules of the sarcolemma?    The action potential in T tubules triggers the release of acetylcholine from the axon terminals of the motor neuron.   The action potential in T tubules triggers closing of sodium channels and opening of potassium channels, which enables myosin cross bridges to form.   The action potential in T tubules opens voltage-sensitive calcium channels in the T tubules, allowing calcium to flow into the sarcoplasm.   The action potential in T tubules causes a shape change in voltage-sensitive proteins that pull open calcium channels in the sarcoplasmic reticulum.

What two types of muscle cells need both extracellular and introcellular calcium to contract? Skeletal muscle and smooth muscle  Skeletal muscle and cardiac muscle  Smooth muscle and cardiac muscle

why does a rapid series of muscle twitches yield a stronger overall contraction than a single twitch?