Venous return & Blood redistribution

• Venous return (VR) is the term used for the volume of blood that returns to the right side of the heart via the venules and veins.
• Starling’s Law

  A decrease in venous return =A decrease in stroke volume = a decrease in Q
• Starling’s Law

  An increase in Venous return = An increase in stroke volume which =A increase in Q
• Stroke volume is dependent on venous return.
• How an increase in Venous return affects ventricular contraction.

  1. Increase in blood to the right atrium , so it stretches the right atrium chamber.
  2. This increases the SA nose firing rate
  3. So HR increases
• At rest VR is sufficient to maintain SV and Q to meet demand for O2.
• Mechanisms aiding Venous return

  • Pocket valves
  • Muscle pump
  • Respiratory pump
  • Smooth Muscle
  • Gravity
• Pocket valve

  Prevents backflow of blood and directs it towards the heart