GENERAL HISTOLOGY

Detailed explanation-1: -The individual cardiac muscle cell (cardiomyocyte) is a tubular structure composed of chains of myofibrils, which are rod-like units within the cell. The myofibrils consist of repeating sections of sarcomeres, which are the fundamental contractile units of the muscle cells.

Detailed explanation-2: -There are two major types of cardiac muscle fibers: myocardial contractile cells and myocardial conducting cells (pacemaker cells). The myocardial contractile cells constitute the bulk (99%) of the cells in the atria and ventricles and are responsible for contractions that pump blood through the body.