arterioles

• What is the diameter of an arteriole?


  Under 100 micrometres
• What do arterioles do?


  Arterioles regulate blood flow and control blood pressure.
• where do arterioles arise from?


  Arise from an arterial branch to link small arteries and capillaries
• What are arterioles lined with?


  smooth muscle (less elastin), which allows their diameter to be controlled by nerves and hormones
• Why do they constrict or dilate?


  To control blood flow
• Why does the smooth muscle contract?

  •vasoconstriction

  •increases resistance

  •increases pressure