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Question
Give reason:
Valves are present in the veins.
Solution
- The main function of the valves in veins is to prevent backflow of blood.
- They are thin walled with semilunar valves to prevent backward flow of blood.
- Blood in the arteries, after being pumped by the heart, are under much higher pressure than blood in veins so there is no need for valves in arteries to prevent back flow.
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RELATED QUESTIONS
The human body has an organ A which acts as a double pump. The oxygenated blood coming from the lungs through blood vessel B enters the upper left chamber C of the double pump. When chamber C contracts, then blood goes into the lower left chamber D. The contraction of chamber D forces the blood to go into a blood vessel E which supplies oxygenated blood to all the organs of the body (except the lungs). The deoxygenated blood coming out of the body organs is taken by a blood vessel F to the right upper chamber G of the pumping organ. Contraction of chamber G forces the deoxygenated blood into the right lower chamber H. And finally, the contraction of chamber H sends the deoxygenated blood into the lungs through blood vessel I.
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