Question

What is the triad system? Where is it located?

Answer 1

Hint: A triad is the structure which is formed by the transverse tubules with a sarcoplasmic reticulum known as the terminal cisterna on either side. Each skeletal muscle fibre has many thousands of triads.

Complete answer:
Triad is a three element complex called a triad. A single T-tubule and the 2 terminal Cisternae form a triad. The number of triads per sarcomere depends on the species for example, in frog muscle there is one triad per sarcomere and in mammalian muscle there are two triad per sarcomere. The triad visible in muscle fibres that have been sectioned longitudinally.
Triads consist of two terminal cisterns of the L-system associated with a central transverse tubule segment. The main function of the triad system is to translate the action potential from the plasma membrane to the sarcoplasmic reticulum and triad allows releasing of $C{a}^{2+}$ when the muscle fibre is excited.
Triad system is located in the skeletal muscles and the triad is an essential skeletal muscle structure. Transverse tubules form the part of the muscle fibres. Only striated muscle and cardiac muscles have triads. Smooth muscles do not contain T-tubules.

Note: There are three types of muscles present in the human body: cardiac muscle, smooth muscle and cardiac muscle. Triad system is only found in the skeletal muscles. The transverse tubules and cisterns are the components of the sarcotubular system.