ANATOMY

Detailed explanation-1: -Cardiac muscle differs from skeletal muscle in that it exhibits rhythmic contractions and is not under voluntary control. The rhythmic contraction of cardiac muscle is regulated by the sinoatrial node of the heart, which serves as the heart’s pacemaker.

Detailed explanation-2: -Smooth muscle cell contraction is slow and depends on the autonomic nervous system. Cardiac muscle cells are mononucleate striated cells, with fast, rhythmic, spontaneous contractions.

Detailed explanation-3: -Smooth Muscle The non-striated (smooth) muscle cell is spindle-shaped and has one central nucleus. Smooth muscle contracts slowly and rhythmically.

Detailed explanation-4: -The cardiac muscle is responsible for the contractility of the heart and, therefore, the pumping action. The cardiac muscle must contract with enough force and enough blood to supply the metabolic demands of the entire body. This concept is termed cardiac output and is defined as heart rate x stroke volume.

Detailed explanation-5: -The SA node starts the sequence by causing the atrial muscles to contract. That’s why doctors sometimes call it the anatomical pacemaker. Next, the signal travels to the AV node, through the bundle of HIS, down the bundle branches, and through the Purkinje fibers, causing the ventricles to contract.