# How does elastic recoil of arteries stop blood pressure going to zero?

1. Feb 10, 2010

### sameeralord

How does elastic recoil of arteries stop blood pressure going to zero and artey collapsing? Thanks

2. Feb 10, 2010

### zomgwtf

Elastic recoil is basically the tendency of some tissues and cells to return to their original shape after it has been deformed. If you think about this maybe you can come to an answer on your own if not then just post again and I'll help you out some more.

3. Feb 10, 2010

### sameeralord

Do you mean volume of the artery increases and then comes back to normal, so there is always some blood remaining? I'm really not sure please can you give me a straight forward answer. Thanks!!

4. Feb 10, 2010

### zomgwtf

Hmmm no...

If the blood pressure were totally dependent on the contractions of the heart then there would only be an increase of pressure when the heart contracts. Then pressure would go back to 0 really quickly until the next contraction. The elastic recoil of the arteries allows the artery to expand as normal but then exert an inward force to create blood pressure. The artery is slowly returning back to it's original shape which is continually 'maintaining' pressure. (because it's continually pressing inwards... the blood pressure is gradually lowering but pressure), this is why blood pressure fluctuates for a normal person between 70-120 mmHg.

To sum this up the inward pressure created by the elastic recoil of the arteries continues to apply pressure on the blood which forces the blood to continue to flow. If there was no pressure exerted on the blood then obviously blood pressure must be 0.

5. Feb 10, 2010

### Doug Huffman

Are you sure?

Someone else asked a question that led me to point them to a Wiggers Diagram that they didn't understand. I didn't feel capable of answering their follow-up questions but thought about it a bit.

Depending where blood pressure is measured, for instance, core volume provides a large determinant for BP. I started to analogize static head for a mechanical pump.

Anyway, look at a Wigger Diagram and note that nowhere does it plot precisely zero pressure. Aortic pressure is low but not zero, ventricle pressure is far from zero, as is arterial/aortic pressure.

6. Feb 10, 2010

### zomgwtf

Well A Wigger Diagram is based on human anatomy... which includes elastic recoil... Imagine that there was no elastic recoil how do you think that would effect this pressure causing flow of blood?

7. Feb 11, 2010

### sameeralord

Thanks Zom I got it. I can see that Doug is pointing something useful but at the moment I'll stick with your explanation.