Page 1 of 1: physio : autoregulation

rsvv79 · Credits: 5404 My Scrapbook

autoregulation is seen in

1. liver
2. muscles
3. kidneys
4. brain

q no 94 pg 60 Salgunan 05 edn.ans given 2,3 and 4.i think it is all

decembermist · Credits: 41201 My Scrapbook

Only RxPG members can see links here! Register or Sign In!

gandalf · Credits: 8395 My Scrapbook

GANONG:

Autoregulation

The capacity of tissues to regulate their own blood flow is referred to as autoregulation. Most vascular beds have an intrinsic capacity to compensate for moderate changes in perfusion pressure by changes in vascular resistance, so that blood flow remains relatively constant. This capacity is well developed in the kidneys (see Chapter 38), but it has also been observed in the mesentery, skeletal muscle, brain, liver, and myocardium. It is probably due in part to the intrinsic contractile response of smooth muscle to stretch (myogenic theory of autoregulation). As the pressure rises, the blood vessels are distended and the vascular smooth muscle fibers that surround the vessels contract. If it is postulated that the muscle responds to the tension in the vessel wall, this theory could explain the greater degree of contraction at higher pressures; the wall tension is proportionate to the distending pressure times the radius of the vessel (law of Laplace; see Chapter 30), and the maintenance of a given wall tension as the pressure rises would require a decrease in radius. Vasodilator substances tend to accumulate in active tissues, and these "metabolites" also contribute to autoregulation (metabolic theory of autoregulation). When blood flow decreases, they accumulate and the vessels dilate; when blood flow increases, they tend to be washed away.

		Sign In New User? Sign Up Sign in to access your control panel and messenger!
				TechZone \| SpiderNevi \| HowTo? \| Scrapbook!