Vascular shunt mechanism

Vascular shunt mechanism

1. Definition.

   • the redistribution of cardiac output around the body from rest to exercise which increases percentage of blood flow to the skeletal muscles.

2. At rest

   • high percentage of cardiac output (Q) distributed to organs
   • arterioles to the organs vasodilate increasing blood flow while arterioles to the muscles vasoconstrict to limit blood flow
   • pre-capillary sphincters dilate, opening up the capillary beds to allow more blood flow to organ cells while constricting closing the capillary beds to the muscle cells

3. During exercise

   • High percentage of cardiac output (Q) is distributed to skeletal muscles.
   • Arterioles and pre-capillarty sphincters serving the capillary beds surround in muscle cells dilate
     • This maximises blood flow, nutrient and gaseous exchange
   • Arterioles and pre-capillary sphincters vaso-constrict around the organs.