Introduction to Transportation in animals and plants

The most purposeful function of the circulation is transport of nutrients to the tissues and removal of cellular excreta. Animal possess body fluids for this purpose. These fluids circulate throughout the body in order to perform their function. So circulatory system is a system of organs and structures which take part inflow of fluids for transport of materials inside an organism. The material transported through circulatory system include water, oxygen, carbon dioxide, nutrients, vitamins, hormones and waste products.

In the body of organisms flow of fluid takes place in definite directions to move the substances.

To perform this mechanical process Circulatory System operates in very systematic manner having following functional features :

• The mode and machinery may vary but the functions are same in all animals.
• To distribute water, nutrients, electrolytes and O₂ upto the cells or tissue and to collect the metabolic wastes (urea, CO₂ etc.) from there.
• To maintain homeostasis, uniformity of heat etc. all over the body.
• To act as the centre for defence system.
• To carry metabolic intermediates e.g. lactic acid (muscle to liver), information molecules    (hormones).
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