• Question: During the process of vasodilation is it just the blood capilleries in the skin that open to allow increased blood flow or is it all of the blood vessels?

    Asked by daleawh to Helen, Jenni, Mark, Martin, Stu on 23 Jun 2011.
    • Photo: Helen O'Connor

      Helen O'Connor answered on 23 Jun 2011:

      I’m sorry I don’t know the answer to that one – I dont know much about the biology and physiology of the human body – my main area of interest is the brain and what we think and feel. I am sure another scientist in another zone would be able to help (maybe microbiology zone?)

    • Photo: Mark Burnley

      Mark Burnley answered on 23 Jun 2011:

      Vasodilation, or vasodilatation in British scientific journals, is a complex and not fully understood process. You can easily do a PhD in this subject and not even scratch the surface of the issues. What we do know is that the most important blood vessels for the control of tissue blood flow are the arterioles (blood vessels between the main arteries and the capillaries). They have smooth muscles wrapped around them which relax when stimulated by things like lactate, nitric oxide, CO2, hydrogen ions and (in particular) increased blood flow. This increased flow causes the blood to rub against the wall of the arteriole, which seems to cause the smooth muscle to relax. The technical term for this is “shear stress”. So it is mainly the arterioles that cause vasodilatation.

Comments