The arterial supply of the heart is built from the right and left coronary arteries, which arise from the aorta.
The cardiac muscle is composed by specialized cells: cardiac myocytes. Kumar et al. (2005) describe five major components in the myocytes: cell membrane (sarcolemma) and T-tubules; sarcoplasmic reticulum; contractile elements; mitochondria; and nucleus. The sarcolemma and T-tubules enable impulse conductions, and the sarcoplasmic reticulum is a calcium reservoir needed for contraction. Mitochondria are crucial components, since they are involved in cardiac contraction by providing a constant supply of ATP to the sarcomeres. Mitochondria are abundant in cardiac tissue, constituting 20% to 40% of cellular volume in energy-demanding zones (Marin-Garcia 2005).
Cardiac muscle is composed of sarcomeres, which are the contractile units with an arrangement of thin and thick myofilaments. The myocytes are composed of many parallel myofilaments arrays of sarcomeres in series, which are responsible for the striated appearance (Kumar 2005). ...Show more