The Structural Adaptations of the mammalian heart to its Functions

It is a muscular/ has cardiac muscles; which are myogenic (do not need nervous stimulation) to pump blood.

It is supplied with vagus and sympathetic nerves; which control the rate of heart beat depending on the body requirements.

It has tricuspid and bicuspid valves between atrium and ventricles; which prevent the back flow of blood to the wrong direction

It has semilunar valves at the base of the pulmonary artery and the aorta; which prevent the back flow of the blood into the right and the left ventricles respectively.

The presence of the valve tendons attached to the atria-ventricular walls; to prevent the atria-ventricular valves from turning inside out due to the changes in the pressure in the ventricles.

The heart is supplied with the coronary artery; which supplies food and Oxygen to the cardiac muscles for their pumping action; the coronary vein in the heart draws away metabolic waste materials.

The heart is enclosed with the pericardial membrane; that secretes a fluid which lubricates it reducing the friction on its walls as it pumps. The pericardial membrane is lined with a layer of fat in the inner wall that act as a shock absorber and holds the heart in position and checks over dilation of the heart.

The heart is divided into two by the atria-ventricular septum; that prevents mixing of oxygenated and Deoxygenated blood.

The left ventricle has a thick muscular wall to pump blood at a higher pressure to the distant body tissues.

The Sino-Atria-Node (S.A.N-the pacemaker region) at the base of the right atrium wall initiates a wave of excitation leading to contraction and relaxation of cardiac muscles.

The Atria-Ventricular Node (AVN) in the heart spreads out the wave of excitation throughout the heart.