Why are valve present contained by vein but not contained by arteries?
Veins need valve to create pressure to pump the blood to the heart. Blood flows away from the heart and, therefore, the pressure is not required.
Simplistically, ruminate of the effort it take to run up a hill, and and how much easier it is to run down it.
Why is not a virtuous question to ask surrounded by science. The answer will always be because it IS!
As you know Arteries move blood away from the heart and vein bring the blood back after going through the capillary.
However the reason for valve in the vein is because it assists in the oneway upward movement of blood from the lower portion of the body, because zilch is forcing it to return to the heart except for body movements and the values.
There is no need for values within the arteries once it gets out of the heart because the blood pressure created by the heart pumping is what cause its movement.
valves contained by your veins are the coolest things ever. your blood have to fight gravity to attain back to your heart.
one entity happening is that your muscles contained by your legs (for example) constrict and relax as you walk - the constricting muscle pushes the blood up your vein - the valves close astern the gush of blood to keep the blood from flowing stern down again.
This process is repeated and your blood inches it's way posterior to your heart (although I think it moves faster than "inching").
So, if you enjoy a damaged spout, the blood keeps flowing subsidise down into your foot (for example) and then your foot swells.
The most coolest piece is to have a Doppler study done of your vein. If you have bring the chance, ask the Dr to place the wand on one of your valve - and then on edge your stomach muscles. Your valve will shut and block the blood. It is really amazing... everyone should try.
Theoretical venous pump pressure change with posture and tone of muscles.. So vein need valve to prevent regurgitation.
Arteries supply blood with systemic blood pressure. So arteries do not necessitate valves.
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