Redistribution of blood

• The process of redistributing cardiac output is called the vascular shunt mechanism
• At rest -

  - only 15-20% resting cardiac output is supplied to the muscles

  • the remaining 80-85% supplies body organs
• during exercise -

  - 80-85% of cardiac output is supplied to the working muscles

  • 15-20% is supplied to the body organs
• the vasomotor control centre -

  chemoreceptors

  • detect an increase in blood acidity and co2 levels

  vasomotor control centre

  • uses the sympathetic nervous system to decrease sympathetic impulses

  this causes the arterioles and pre capillary sphincter to vasodilate

  this results is an increased blood supply to the muscle
• baroreceptors

  • detect and increase in blood pressure

  vasomotor control centre

  • uses the sympathetic nervous system to increase sympathetic impulses

  this causes the arterioles and pre capillary sphincters to vasoconstrict

  this results in a decreased blood supply to the main organs