How would you explain muscle cell contraction were there no

How would you explain muscle cell contraction were there no T tubules?

Solution

A T-tubule (or transverse tubule) is a deep invagination of the sarcolemma (plasma membrane of skeletal muscle and cardiac muscle cells). Function of T tubes is to spread the action potential across the muscle cell and down into it. As the action potential travels down the t-tubule it stimulates the terminal cisternae to release calcium ions that bind to the the troponin which changes shape moving the tropomyosin away from the myosin binding sites on the actin. This allows actin and myosin to bind and the muscle to contract. If there are no T tubules then muscles would experience \"complete tetany\", or total contraction without release, due to the lack of acetylcholine esterase. Muscle doesn\'t work so well anymore.