Body fluids and Circulation

Circulation is the transport of nutrients, oxygen, CO2 and excretory products to the concerned tissues or organs. For circulation, simple organisms (sponges, coelenterates etc) use water from their surroundings. Complex organisms use body fluids (blood & lymph) for circulation. CIRCULATORY PATHWAYS Circulatory system is 2 types- Open and Closed. § Open circulatory system: Here, the blood pumped by the heart passes...

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Excretory Products and their Elimination

Excretion is the elimination of metabolic wastes like ammonia, urea, uric acid etc. from the tissues. It is 3 types: 1.  Ammonotelism: Process of excretion of NH3. Ammonotelic animals: Aquatic invertebrates, bony fishes, aquatic amphibians, tadpoles, aquatic insects etc.NH3 is highly toxic. So excretion needs excess of water. 2.  Ureotelism: Process of excretion of urea. In liver, NH3 is converted into less toxic urea (for conservation of water). This is called Ornithine cycle.  For excretion...

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