DESCRIBE THE FUNCTIONS OF VARIOUS PARTS OF THE MAMMALIAN HEART (20MKS)
Describe the functions of various parts of the mammalian heart (20mks)
Pericardial membrane – secretes a lubricating fluid.
- encloses and protects the heart.
- prevents over-dilation of the heart.
Fat layer – prevents mechanical shock/cushions the heart
Blood vessels – coronary artery supplies the heart muscles with oxygen and nutrients
- coronary vein carries away CO2 and waste products of metabolism
Valves – prevent backflow of blood into the auricles and into the ventricles
Valve tendons – prevents valves from turning inside out when systolic pressure is high.
Ventricles – are thick walled to pump blood out of the heart
S.A.N (Sino-Atrial Node) – acts as a pacemaker to set pace for heart to beat.
Cardiac muscles – contract and relax without fatigue
Vagus nerve parasympathetic branch – slows down the heartbeat
Vagus nerve sympathetic branch – speeds up the hear beat
(20mks)
Comments
Post a Comment