Ultrafiltration Flashcards
Ultrrafiltration?
Filtration of small molecules from the blood plasma to the lumen of the nephron under high pressure
Another name for the lumen of the nephron?
Bowman’s capsule, this is where ultrafiltration occurs
What causes high pressure at the glomerulus 2
High hydrostatic pressure in renal artery caused by LV systole
Difference in diameter of afferent and efferent lumens
A greater than E, increased H.P
What are the 3 layers through which small molecules have to pass to move from the blood plasma to the outside of the glomerulus
Endothelium of the glomerulus capillaries
Capillary basement membrane of collagen
Podocytes
Podocytes?
Kidney cells which wrap around the glomerulus capillaries
They have arm like extensions called pedicels
Name for pores in endothelium
Fenestrae
How does the basement membrane behave in ultrafiltration
Selective barrier, acts as a molecular sieve only allowing passage of very small molecules
How can the blood leaving the glomerulus through the efferent arteriole be described, why
Low water potential bc retained all plasma proteins and WBC, RBC, platelets (=high conc) but lost alot of water
What is the filtrate , and components
Solution forced from blood plasma during ultrafiltration
Contains H2O
amino acids
urea
glucose
ions (Na+)
vitamins
What type of epithelial cells are podocytes
squamous
Name for large gaps between pedicels
filtration slits
Glomerular filtration rate?
Rate fluid passes from blood in glomerular capillaries to lumen of Bowman’s capsule~ 125 cm3 min-1
Overall what causes ultrafiltration
Net affect of high hydrostatic pressure and low solute potential in the lumen of the Bowman’s capsule
What is the size of molecules that can pass out of the capillaries
Less than 68000 RMM
