Diuretics-Duan Flashcards
What are some important things that the kidneys secrete? An important extra fcn of kidney?
secretes: erythropoietin, renin, activates vit D, prostaglandin
extra fcn: gluconeogenesis
What is the equation for net filtration pressure @ the glomerulus?
NFP = (Favoring force) – (Opposing force)
Favoring Force: Capillary Blood Pressure (BP)
Opposing Force: Blood colloid osmotic pressure (COP)
Capsule Pressure (CP)
What is the equation for GFR?
GFR=urine conc’n X urine flow/plasma conc’n
What is a good estimate of GFR?
creatinine clearance
What would the following do to GFR?
Renal Blood flow up
Plasma protein down
hemorrhage
Renal Blood flow up: GFR up
Plasma protein down: GFR up, + edema
hemorrhage: BV down, GFR down
What are 3 forms of GFR regulation?
- renal autoreg
- neural reg
- hormonal reg
Where are cortical nephrons found? Juxtamedullary nephrons?
Cortical: found in the renal cortex (70-80% of all nephrons). loop only a little into the medulla
Juxtamedullary: found w/ glomerulus in bottom of cortex, & loop of Henle into the medulla
What is the osmolarity of the cortex & the medulla of the kidney?
Cortex: isoosmotic w/ the blood 300 mOsm
Medulla: hyperosmotic, acts to concentrate urine
Describe reabsorption in the kidney.
A two-step process beginning with the active or passive extraction of substances from the tubular fluid into the renal interstitium (the connective tissue that surrounds the nephrons); then these substances are transported from the interstitium into the bloodstream . These transport processes are driven by Starling forces, passive diffusion, and active transport.
What happens in the PCT? What are 2 important exchangers found here?
65% of water reabsorbed here
bicarb pumped back into the blood
Na+/H+ exchanger
carbonic anhydrase found here
The Loop of Henle faces a concentration gradient. Which part of the loop is permeable for water reabsorption? Which part is impermeable?
15% of water reabsorption happens in the loop
Descending: permeable
Ascending: impermeable–diluting portion
What happens in the thick ascending limb of the loop of Henle?
x
How does the gradient of the urine change throughout the loop of Henle?
water is reabsorbed in the beginning. Hyperosmotic by the bottom.
ascending reabsorbs ions, but not water.
urine bcomes hypo osmotic before becoming the DCT.
What happens in the DCT?
relatively impermeable to water, continue to dilute urine
transports Na+ & Cl- back via Na+/Cl- cotransporter
calcium is actively reabsorbed here, which is regulated by PTH
What are the 2 important cell types found in the collecting tubule?
- principal cells
2. intercalated cells-alpha & beta cells participate in acid base homeostasis
