REGULATION OF WATER AND ELECTROLYTE LEVELS IN PLASMA AND INTERSTITIAL FLUID Flashcards
What is the Law of capillaries?
the control mechanism for water exchange between plasma and interstitial fluid consists of four pressures
Law of capillaries - the control mechanism for water exchange between plasma and interstitial fluid consists of four pressures. What are the four pressures?
blood hydrostatic and colloid osmotic pressures on one side of the capillary membrane and interstitial fluid hydrostatic and colloid osmotic pressures on the other side; two of the pressures form a vector in one direction and the other two in the opposite direction
Blood hydrostatic pressure (BHP) What does it do?
forces fluid out of capillaries into interstitial fluid (IF)
Blood colloid osmotic pressure (BCOP) What does it do?
draws fluid from IF into capillaries
Blood colloid osmotic pressure (BCOP) What does it do?
draws fluid from IF into capillaries
Interstitial fluid hydrostatic pressure (IFHP) What does it do?
forces fluid out of IF into capillaries
Interstitial fluid colloid osmotic pressure (IFCOP) What does it do?
draws fluid from capillaries to IF
The rate and direction of fluid exchange between capillaries and interstitial fluid are determined by what?
the hydrostatic and colloid osmotic pressures of the two fluids
The rate and direction of fluid exchange between capillaries and interstitial fluid are determined by what?
the hydrostatic and colloid osmotic pressures of the two fluids
Some principles about transfer of water between blood and interstitial fluid. What are they? (there are 4)
- No net transfer of water occurs as long as (BHP + IFCOP) = (IFHP + BCOP)
- A net transfer of fluid occurs when (BHP + IFCOP) does not equal (IFHP + BCOP)
- Fluid shifts out of blood into interstitial fluid whenever (BHP + IFCOP) > (IFHP + BCOP)
- Fluid shifts out of interstitial fluid into blood whenever (BHP + IFCOP)