2007-03-20 17:51:45 · 5 answers · asked by Vanny 1 in Science & Mathematics ➔ Biology
Our arteries takes the flow of our blood from the heart so they need to withstand the direct pressure of the pumping heart. In fact, when you take your pulse rate at your wrist or on your neck, you are feeling the arteries "pulse" from the pressure.
On the other hand, our veins carry the flow of blood going back to the heart on the way to the lungs to be re-oxygenated. This force is only a secondary flow so there is no real direct pressure.
2007-03-20 18:06:02 · answer #1 · answered by shaboom2k 4 · 1⤊ 0⤋
The arteries are thicker so they can stand up to the huge preassure of blood from the hear, but by the time the blood gets to the veins its a lot slower and have very little preassure. I think the thinness also lessens resistance to the weak blood flow. The veins have valves to stop the blood flowing backwards.
2007-03-20 18:00:21 · answer #2 · answered by Anonymous · 0⤊ 0⤋
The thicker walls of the arteries and arterioles serve two purposes. One, they absorb the pulsatile flow from the heart and transmit the flow more continuously. Second, the arteries and arterioles have smooth muscle that surrounds them and that allow the arteries to constrict when necessary- like when you need to increase blood pressure to vital organs, or if you're hemorrhaging, or if your blood pressure is too low. These vessels can also dilate if need be in other circumstances.
2007-03-20 18:08:06 · answer #3 · answered by misoma5 7 · 0⤊ 0⤋
More blood pressure. It would be correct to understand that even smaller veins withstand similar pressures, and the reason they are thicker are not only because there is more pressure, but there is more blood in these areas as well.
2007-03-20 18:18:51 · answer #4 · answered by Anonymous · 0⤊ 0⤋
To stand up to the pressure created by the pumping action of the heart.
2007-03-20 17:55:42 · answer #5 · answered by Loulabelle 4 · 2⤊ 0⤋