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Cardiovascular Physiology
The Microcirculation
1. What are the transcapillary exchange mechanisms?
What is diffusion?
  • The movement of solutes occurs down a concentration gradient utilizing micropores or clefts between adjacent endothelial cells in the capillary wall
  • What is pinocytosis?

  • It is the main route for the flow of plasma proteins into the interstitium since capillary pores are too small to allow their passage. Pinocytosis involves the invagination of the capillary endothelial cell membrane to form an intracellular vesicle that contains plasma including plasma proteins. These vesicles cross the capillary endothelial cell from the blood stream side to the interstitial fluid side. The vesicles fuse with the outer membrane of the capillary endothelial cells and discharge their contents into the interstitial space.
  • What is ultrafiltration?

  • Involves the movement of fluid as determined and discussed previously under the influence of Starling Forces.
  • 2. Identify the components of the microcirculation
  • The small arteriole
  • The capillary
  • The venule
  • The microcirculation is the site of gas, nutrient and metabolite exchange
  • production