Guyton chapter 7 | Excitation-contraction coupling | T-tubules | sarcoplasmic reticulum | lecture 42 скачать в хорошем качестве

Guyton chapter 7 | Excitation-contraction coupling | T-tubules | sarcoplasmic reticulum | lecture 42

Excitation contraction coupling is a process through which, excitation of muscles is combined with contraction of the muscles. The excitation process is completed with the help of #T-tubules, which is a system of tubules to takes action potential deep inside a muscle fiber. The nerve fibre can activate the muscle fiber membrane, but the T-tubule or transverse tubules takes the impulse deep inside the muscle fiber. Once the impulse reach inside the cell, it activates the #sarcoplasmicreticulum. Sarcoplasmic reticulum has two parts, a cristae and tubules. The cristae of sarcoplasmic reticulum is attached with T-tubule, and it gets excited by the incoming impulse.  Once excited, the sarcoplasmic reticulum secrets Alot of calcium ions, the calcium combines with heads of the cross Bridges of the myosin filaments and cause contraction.  Once the contraction of actin and myosin filaments has occurred,  the calcium ions are taken up again into the sarcoplasmic reticulum.  With uptake of calcium the process of excitation contraction coupling comes to an end.