Fluid Compartments and Physiology Flashcards
(27 cards)
what % of BW is TBW?
60%
what % of TBW is ICF?
2/3
what % of TBW is ECF?
1/3
what % of ECF is interstitial fluid?
75%, 3/4
between the ICF and ECF compartments, why does fluid move?
because of osmotic forces
what determines movement of fluid between ECF and ICF?
osmolality
what is the main component of osmolality?
Na+
what does hydrostatic pressure cause?
fluid leakage out of the vessel: heart pumping and pushing blood forward
capillary hydrostatic pressure is primarily dependent on
venous pressure
arterial pressure is not translated across precapillary sphincter
venous stasis will increase capillary pressure
how does venous stasis affect capillary pressure?
it increases it
oncotic pressure causes fluids to go
INTO the vessels: keeps fluid INTO the vessels
what pressure makes fluids go INTO the vessels?
oncotic pressure
what does oncotic pressure depend on/
proteins!! # particles = concentration/molecular weight
primarily 70-80% due to albumin
what is Kfc?
filtration coefficient: tight junctions
what does Kfc depend on?
- capillary surface area: large surface area will increase Kfc
- hydraulic conductivity (leakiness) of the vessels: endothelial community
T/F: the liver and kidney have relatively tight vessels
False, they have leaky vessels: have a large net movement of fluid out of blood vessels in these organs
the brain and muscle have tight vessels!
why does the liver and kidney have leaky vessels?
have a large net movement of fluid out of blood vessels in these organs
what organs have tight vessels?
brain and muscle
what is the reflection coefficient? σ
relative permeability of the capillary bed to protein
reflection = bouncing back of the protein against the endothelial cells = how much the barrier resists passage of solute
depends on tissue: low in liver, high in kidney
lungs have low Kfc and high σ: relatively non leaky
is σ (reflection coefficient) high or low in the liver and kidney?
low in liver: ie the liver capillary bed is very permeable to proteins
high in kidney: ie the kidney is resistant to proteins
do the lungs have high or low Kfc and σ?
high σ
low Kfc
relatively non leaky
what is the endothelial surface layer?
mesh-like gel matrix layer covering the luminal aspect of blood vessels/endothelial cells: creates a physical barrier between the blood flow and the endothelial cells: protects cells
the ESL is comprised of
- structural scaffold
- endothelial glycocalyx (EG)
- associated molecules: albumin, fibrinogen, oromucosoid
what is the 4th starling force?
lymphatic drainage
