MUSCLE PHYSIOLOGY

Detailed explanation-1: -Myofibrils are long contractile fibres, groups of which run parallel to each other on the long axis of the myocytes (long single multinucleated cells that combine to form the muscle). The myocytes run parallel to each other on the long axis of the cell.

Detailed explanation-2: -The region between two Z membranes is called a sarcomere, which is regarded as the basic contractile unit. The regular arrangement of the myofilaments within the myofibrils is repeated across the muscle fibre, giving it its characteristic striated appearance under the microscope.

Detailed explanation-3: -Myofibrils are contractile units within the cell which consist of a regular array of protein myofilaments. Each myofilament runs longitudinally with respect to the muscle fiber. There are two types: the thick bands and the thin bands. Thick bands are made of multiple molecules of a protein called myosin.