Chapter 8 1c Excitation-Contraction Coupling, Contraction, Relaxation Flashcards
what does the sarcoplasmic reticulum in the muscle cell do?
stores calcium
What is the channel along the muscle cell that allows the action potential to enter the muscle cell?
t tubule
What does the t tubule cross through in the muscle cell?
the sarcoplasmic reticulum
what does the sarcoplasmic reticulum do when the action potential flows through the t tubule?
releases calcium all throughout the muscle cell
What does the calcium released from the sarcoplasmic reticulum after the action potential travels through the t tubule do?
activates the next phase of muscle physiology, excitation-contraction coupling
what covers the myosin binding sites on the thin (actin) filament when a muscle is at rest?
tropomyosin
What does the calcium released from the sarcoplasmic reticulum after the action potential travels through the t tubule do?
what is this phase of muscle physiology called?
binds to the troponin on the thin (actin) filament so the myosin binding sites open so the myosin can attach to the actin for muscle contraction
excitation-contraction coupling
which muscle is at rest and which one is contracting?
a at rest
b contracting
do the myosin and actin change shape during a contraction?
no, they just overlap
How does ATP perform in a muscle contraction?
ATP turns to ADP and a Phosphate
They bind to the myosin
Myosin binds to actin
Phasphate is released
ADP pushes the muscle for contraction
the same cycle happens to release the muscle from the contraction
What happens to the ACh in the relaxation phase of muscle contraction?
It is eaten up by acetylcholinesterase (AChE) and gets placed back in vessicles for future use
What happens to the calcium in the muscle cells in the relaxation phase of muscle contraction?
it gets moved back into the sarcoplasmic reticulum by active transport with ATP
