Heart The human heart The heart is a muscular organ in most animals, which pumps blood through the blood vessels of the circulatory system.[1] Blood provides the body with oxygen and nutrients, as well as assists in the removal of metabolic wastes. In humans, the heart is located between the lungs, in the middle compartment of the chest.[3] In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right atria; and lower left and right ventricles.[4][5] Commonly the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart Continue reading →

Troponin, or the troponin complex, is a complex of three regulatory proteins (troponin C, troponin I, and troponin T) that is integral to muscle contraction[2] in skeletal muscle and cardiac muscle, but not smooth muscle. Discussions of troponin often pertain to its functional characteristics[3] and usefulness as a diagnostic marker[4] or therapeutic target[5] for various heart disorders, in particular as a highly specific marker for myocardial infarction or heart muscle cell death.[3] Troponin is attached to the protein tropomyosin and lies within the groove between actin filaments in muscle tissue. In a relaxed muscle, tropomyosin blocks the attachment site for the myosin crossbridge, thus preventing contraction. Continue reading →