Theories Of Autoregulation

Th e capacity of tissues to regulate their own blood fl ow 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 fl ow remains relatively constant. Th is capacity is well developed in the kidneys (see Chapter 37 ), 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 fi bers that surround the vessels contract. If it is postulated that the muscle responds to the tension in the vessel wall, this theory …show more content…
Vasodilator substances tend to accumulate in active tissues, and these
“metabolites” also contribute to auto-regulation (metabolic theory of autoregulation). When blood fl ow decreases, they accumulate and the vessels dilate; when blood fl ow increases, they tend to be washed