Describe the structural adaptations of the mammalian heart to its function

• It has cardiac muscles which are myogenic and hence contract without nervous stimulation to pump blood;
• It is supplied by the vagus and sympathetic nerves; which controls the rate of heartbeat; (depending on the body’s physiological requirements)
• It has tricuspid valves and bicuspid valves; (between the atrium and ventricles) which prevent backflow of the blood into the right and left ventricles respectively.
• The presence of valve tendons attached to the walls of ventricles and to the atrium; to prevent atria-ventricular valves from turning inside out due to changes in the pressure in the ventricles;
• The heart is supplied by the coronary artery; which supplies food and oxygen to the cardiac muscle for their pumping action; the coronary vein in the heart removes metabolic wastes;
• The heart is enclosed by the pericardium membrane; which secretes pericardium fluid that lubricates it (reducing friction on the walls as it pumps);
• The heart is divided into two by the atrioventricular septum; which prevents the mixing of oxygenated blood and deoxygenated blood;
• The left ventricle has a thick muscular wall to pump blood at higher pressure to the distant body issues;
• The outer part of the pericardium is covered with a fatty layer; which acts as a shock absorber to keep the heart in position.
• The Sino Atrial Node (SAN), the pacemaker region which initiates the wave of contraction leading to contraction and relaxation of muscles;
• The atrioventricular node (AVN) in the heart spreads out waves of contraction throughout the heart creating the heart beat;