How mammalian heart is adapted for its function
The heart has atrioventricular/tricuspid and bicuspid valves and semi-lunar valves which allow blood to flow in one direction/prevent backflow of blood; valves have non-elastic chordae tendonea/ tendons which prevent atrioventricular valves from turning inside out into auricles during ventricular systole;
The heart has thick muscular walls which contract to pump and push blood; The heart is made of cardiac muscles which are myogenic/contract and relax without fatigue; the heart has sino-atrio node and atrio-ventricular node which initiate the cardiac muscles impulses; hence stimulate the contraction of the atria and ventricles respectively;
The heart is served with vagus and sympathetic nerves which regulate the rate of heart beat; (depending on the body’s physiological requirements) The cardiac muscles are served by coronary artery and coronary vein, coronary artery supplies oxygen/nutrients; to heart muscles whereas coronary vein remove metabolic wastes/carbon (iv) oxide;
The heart has specialized interconnected cardiac purkinje fibres which spread the wave of excitation throughout the heart muscles; the heart has four chambers which hold blood briefly before it is pumped to the lings and the rest of the body.
The heart has a septum wall that prevents mixing of oxygenated blood (on the left o the heart) from mixing with deoxygenated blood (on the right side of the heart) . The heart has venacava and pulmonary vein that transport blood to the auricles (from the rest of the body) and lungs respectively, The pulmonary artery and aorta transport blood to the lungs, and the rest of the body (respectively)
The heart is enclosed by pericardium memberane which prevents it from overstretching, the pericardium secretes the pericasdial fluid which lubricates the heart and reduce friction as the heart moves with the inner membrane; the pericardium is converted with a layer of fat that acts as shock absorber.
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