Intrinsic Regulation of blood flow - autoregulation

These mechanisms provide a more localized regulation and are particularly important in the kidney, brain and skeletal muscle. There are two types:

1. Myogenic Control describes the ability of vascular smooth muscle to respond to changes in blood pressure. For example if systemic pressure decreases cerebral vessels dilate to maintain blood flow to the brain. If systemic pressure rises, as in hypertension, cerebral vessels constrict to protect smaller more delicate vessels and prevent cerebral haemorrhage.


2. Metabolic Control. Small blood vessels respond to metabolites (vasoactive) released by surrounding tissues. In most cases these metabolites cause vasodilatation. Thus if blood flow is sluggish metabolites are not dispersed as effectively, they accumulate and increase blood flow by causing vasodilatation. Important promotors of vasodilatation are: decreased oxygen concentration; increased CO₂ concentration; decreased pH; release of adenosine or K⁺ from tissue cells.