Capillary Filtration And Lymph Flow Flashcards
What do caps allow for
Exchange of cargo between blood and tissues such as nutrients, oxygen, electrolytes, wastes, CO2 out
Small stuff, fluid portion of blood
What does the endothelial allow for in caps
Diffusion of small solutes and water, usually no proiteins or cells because they are too big
What does filtered fluid become
The interstitial fluid (intercellular)
How do non-permeable things get across endothelium
Cross between the pore, PARACELLULAR
How do larger things get across the endothelium
Diffuse across the endothelial cells if permeable- TRANSCELLULAR
Where are there small pore sizes in the endothelium
Brain and eye
Where are there large pore sizes in the endothelium
Kidney and liver
What determines how selective the endothelium is?
Pore size
Thickness of the walls of lymphatic
Thin walled
Where are lymphatic found
Tissue surrounding cap beds
What serves as drains for interstitial fluid
Lymphatics
Where does lymph drain back into
Subclavian vein
What are the drain pipes for the interstitial fluid
Lymphatic
Process by which blood plasma is filtered across the capillary membrane to make the interstitial fluid
Ultrafiltration
Same process for making CSF, aqueous humor, urine, just modified
What does ultrafiltration depend on
4 factors and permeability of endothelium are responsible for formation
What are the 4 factors that determine ultrafiltration
- Capillary pressure (BP inside caps) Pc
- Plasma colloid osmotic pressure (albumin inside caps) Pi(c)
- interstitial fluid pressure (essentially 0) P(tis)
- interstitial fluid colloid osmotic pressure (usually 0) pi (tis)
Filtration coefficient, similar to diffusion coefficient. How permeable the caps are
Filtration =Kf*net filtration pressure
What determines how much fluid moves
Net filtration pressure
Pc
Hydrostatic pressure inside the capillaries
P(tis)
Hydrostatic pressure inside the tissue
PI(c)
Osmotic pressure inside the caps
PI(tis)
Osmotic pressure inside the tissue
What pressures favor filtration
Capillary pressure (Pc) and interstitial fluid colloid osmotic pressure
Fluid leaving the cell
What pressure favor reabsorption
Plasma colloid osmotic pressure and interstitial fluid pressure
Fluid coming in
Increasing which of the following would increase interstitial fluid formation (cap filtration)
Capillary hydrostatic pressure
Pressure in vessel pulling fluid towards it
Administration of an alpha 1 receptor antagonist (blocker) would _______ filtration by increasing __________
Increase; capillary hydrostatic pressure
How do you increase hydrostatic pressure
Block lymphatics, build up of fluid
If hydrostatic pressure and on otic pressures in the body is the same, why does the liver produce more interstitial fluid than the brain
Liver capillaries have an increased Kf (bigger holes)
Increase filtration
Increase interstitial fluid formation
Increasing Pc (Capillary pressure) does what to filtration
Increases it
Dilate arterioles, constrict venules, increase CVP
What does increasing tissue osmotic pressure do to filtration
Increases it
Block lymphatics, increase permeability to proteins
What does decrease in capillary osmotic pressure do to filtration
Increases it
Liver failure, starvation
What does decreasing tissue pressure do to filtration
Increases it
Increase lymph drainage (not really possible)
What does increasing Kf do to filtration
Increases it
Burns, inflammation
Increases permeability
Changes in _________ resistance affects filtration more than _______
Venous
Arteriolar
What side is mroe important in cap flow
Venous
What does a decrease in capillary pressure do to filtration
Decreases it
Constrict arterioles, dilate venules, decrease CVP, hemorrhage
Decrease filtration
Reduce interstitial fluid formation
What happens to filtration when you decrease tissue osmotic pressure
Decreases it.
More lymph drainage
Rid of protein that got out
What happens when tou increase osmotic cap pressure to filtration
Decreases filtration
Dehydration, some cancers, hemolytic anemia
What happens to filtration when you increase pressure of tissue
Decreases it
Edema, physical compression of tissue
What happens to filtration when you decrease Kf?
Decreases filtration
Thickening of vessel walls, fibrosis
All solutes move across the cap by ______
Diffusion
Cap pores slow large solutes
What is diffusion of small or soluble molecules limited by
Blood flow
What is flow (perfusion) limited
Diffusion of small or soluble things
Equibrialtes qucikly
Large or insoluble molecule are limited by
Pore size
What is diffusion limited
Large or insoluble model veils
Equibrilates slowly or not at all
Distance to cell matters
To increase tissue concentration of flow limited molecules, you must increase what
Bloodflow
To increase concentration of diffusion limited molecules you must increase
Diffusion rate
A patient has a chronic pulmonary artery hypertension, reduces cardiac hypertension, and peripheral edema. Which of the following is the most direct cause of the edema
Increased venous cap pressure (favors filtration)
What is the difference between left and right heart failure
Left heart failure
- lungs get fluid
Right hear failure
-fluid in periphery
