The food which enters through the mouth is digested mainly in the
intestine and oxygen which enters through nose is present in lungs. Both are
far away from the site of the activity e.e cell or tissue. Therefore, it needs
to be carried to or transported to its final destination. At the same
time, waste products and cabondioxide have to be carried away from the
cells or tissues and removed from the body, as they are poisonous and harmful.
Both these functions are performed by the Blood Vascular System which
acts as the circulating medium in humans. the circulatory system has two major
components - a pulsatile pump (the heart) and a system of tubes or
channels (the blood vessels).
Structure
Heart is four -chambered organ made up of two upper chambers -right and left atria and
two lower chambers -right and left ventricles. The two atria and ventricles
are separated from each other by a partition -the inter-atrial septum or inter-ventricular
septum, respectively. However, the atrium and ventricle of either side
communicate with each other through valves. The right atrium and ventricle are
connected through tricuspid valve ("Tri" means 'three') with three
flaps or cusps and left chambers are joined through bicuspid valve with
two flaps or cusps.
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