Describe how the mammalian heart is structurally adapted to its function.

K.C.S.E Biology Q & A - MODEL 2016PP2QN08

Describe how the mammalian heart is structurally adapted to its function.

answers

•  Cardiac muscles which contract and relax continually without fatigue/myogenic
•  Cardiac muscles are interconnected / a synclination form of network of fibres to rapidly and uniformly spread the contractions
•  Divided into four chambers for Atria to receive blood and ventricles to pump blood out of the heart
•  Divided into two sides by a longitudinal septum to prevent mixing of oxygenated and deoxygenated blood / for double circulation
•  Ventricles have thicker walls to generate high prevention pressure to pump blood
•  Wall of the left ventricle is thicker than that of right ventricle to pump blood over a long distance.
•  Have valves to prevent back flow of blood
•  Cuspid valves have strands of connective tissues / tendinious codes / valve tendons to prevent turning in/out during systole / when ventricles contract
•  Has coronary artery to nourish / supply oxygen to the heart/muscles; has a coronary vein to remove metabolic wastes carbon(iv)oxide
•  Enclosed by a pericardium to keep it in position / prevent over dilation
•  Pericardium secretes pericardial fluid to reduce friction / absorbs shock
•  Has Sino Artrio Node (SAN) which acts as a pacemaker
•  Has Atrio Ventricular Node (AVN) which relays contraction waves from SAN to the puncinje tissues
•  Has puncinje tissue / bundle of HIS to relay waves from AVN to the ventricular myocardium
•  Cardiac muscles have numerous mitochondria to generate energy for the muscular contractions
•  Has venacava and pulmonary vein to supply blood to the heart.
•  Has aorta and pulmonary artery to transport blood away from the heart.