What Is the Physiological Basis of an Efficient Perfusion of Internal Organs or Hind-limbs?
After sudden or slowly progressing stenosis of a major artery, the survival of ischemic limbs or internal organs like heart and brain can be guaranteed only if relatively large blood volumes per unit of time are made available to perfuse the ischemic territories. Taking the law of Ohm into account, blood pressure, resistance, and blood flow are closely linked to each other. The bigger the diameter of a vessel, the lower the resistance and hence the higher the blood flow. Preexisting collateral anastomoses, for instance, have the ability to conduct, after adaptive growth, relatively large blood volumes per unit of time. In many cases, collateral arteries can minimize or even prevent the fatal consequences of sudden arterial obstruction.16 17 This protective role of collateral arteries depends largely on their ability to increase their vessel diameter in a very short period of time by active proliferation. In the rabbit hindlimb, for example, collateral arteries increase their lumen 20-f
