The action potential generated travels deep into the cell by the aid of t-tubules, which are invaginations of the sarcolemma. When muscle is stimulated by Action Potential, the t tubules are triggered to release Ca2+ ions from the Terminal cristae of the Sarcoplasmic reticulum, which causes muscle contraction. They help spread the impulse so that the cell is able to contract at the same time.
- ↑ A.Fullick, J.Locke, P.Bircher. A level biology for OCR. Oxford University Press, Great Clarendon Street, Oxford, OX2 6DP, United Kingdom. 2015.