When Ach enters the synaptic cleft (gap) it open chemically gated sodium channels that starts an action potential spreading through the sarcolemma of the myofibril. This action potential spreads down the T-tubules and "shocks" the sarcoplasmic reticulum into releasing calcium ions.
When an influx of Na+ produces end-plate potential in a muscle fiber, voltage-sensitive receptors cause channels on the sarcoplasmic reticulum (SR) to open. This releases stored Ca2+ inside the SR out into the cytosol.
Hope this helps!
~w
The sarcoplasmic reticulum (SR) releases calcium ions into the cystosol when the action potential travels down the t-tubules that border the SR.
The action potential spreading along the muscle cell causes calcium gates in the sarcoplasmic reticulum to open and to release calcium ions almost immediately.
After ATP powers the release of the myosin head from the actin molecule, the calcium is pumped back into the sarcoplasmic reticulum via active transport.
arrival of a action potential
CALCIUM ions
an action potential
It is pumped by active transport.
vbh
calcium released by sarcoplasmic reticulum.
The Ca2+ ion concentration of the sarcoplasmic reticulum will be greater in a resting muscle
sarcoplasmic reticulum
sarcoplasmic reticulum
One major function of the sarcoplasmic reticulum is the regulate the intracellular levels of CA2+ for contractions and relaxation for muscles. Sarcoplasmic Reticulum is a storage organelle with calcium ion pumps on membrane and use ATP to fuel pumps to get calcium ion inside it's cell and holds it. When contraction of muscle is needed calcium ion is then dumped into cytoplasm to cause contraction.
The sarcoplasmic reticulum is known for its storage of calcium ions in muscle cells.
in the sarcoplasmic reticulum of a muscle fiber/cell.
Sarcoplasmic reticulum
The sarcoplasmic reticulum is a special type of smooth endoplasmic reticulum. It releases calcium ions during muscle contraction and absorbs them during relaxation.
sarcoplasmic reticulum
sarcoplasmic reticulum
Calcium (Ca+2)
In the sarcoplasmic reticulum (smooth er).
calcium released by sarcoplasmic reticulum.
The Ca2+ ion concentration of the sarcoplasmic reticulum will be greater in a resting muscle
sarcoplasmic reticulum
Terminal Cisternae