Which of the following best describes the function of t-tubules?
a. transmit action potentials
b. store and release calcium ions
c. remove calcium ions from sarcoplasm
d. store and release neurotransmitter
e. all of the above

b. store and release calcium ions

Explanation:

The two major functions of the T - tubules are as follows -

1. the T - tubules propagates the action potential of the plasma membrane into the muscle cells interior through the voltage - gated Na ⁺ and K⁺ channels .

2. The cation potential which is carried by the T - tubules helps to regulate the opening and the closing of the calcium ion channels present in the sarcoplasmic reticulum . The resulting change in the cytosolic calcium ions concentration triggers the contraction of the myofibrils .