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50 terms

tubular reabsorption and secretion

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peritubular capillaries
reabsorption occurs into what
peritubular capillaries
secretion occurs from what
ureters and bladder
excretion occurs where
inulin
this substance is freely filtered but not reabsorbed
urea
this substance is freely filtered but part of the filtered load is reabsorbed back in the blood
glucose
this substance is freely flitered but is not excreted in the urine bc all the filtered substance is reabsorbed from the tubules in the blood
acids and potassium
this substance is freely filtered and is not reabsorbed but is secreted from the peritubular capillary blood into the renal tubules
creatinine
what is freely filtered across the glomerulus and is to a first approximation not reabsorber secreted or metabolized by the neprhon, the amount filtered is the same as excreted
inulin
what is the perfect wat to check renal clearance
creatinine
what is a good way to watch renal progression
renal clearance
what is the rate at which substances are removed (cleared) from the urine and is the ratio of urinary excretion : plasma excretion
clearance (GFR)
what = (urinary conc x urine flow) /plasma conc
creatinine clearance
what is the std test to estimate GFR
twice
dec the GFR by 50% will inc the plasma creatinine to what of normal if creatinine production by the body stays constant
glucose, aa, electrolytes
what 3 main things are reabsorbed and indicate that the tubule is highly selective
urea and creatining
waste products such as what are not actively reabsorbed
saturation of receptors
the transport maximum of tubular reabsorption is based on what
transport maximum
what is the maximum rate at which glucose can be reabsorbed from the tubules
reabsorption
what is when filtered water and solutes go from the tubular lumen across the tubular epithelial cells through the renal interstitium and back into the blood
passive diffusion or active transport
solutes are transported via the transcellular path by what
diffusion
solutes are transported via the paracellular path btwn cells by what
osmosis
water is transported thru the cells and btwn the tubular cells by what
ultrafiltration
transport of water and solutes from the interstitial fluid into the peritubular capillaries occurs by what that is also called bulk flow
sodium-potassium pump
what transports sodium from the interior of the cell across the basolateral memb, creating alow intracellular sodium conc and a neg intracellular electrical potential
sodium
the low intracellular sodium conc and the neg electrical potential cause what ions to diffuse form the tubular lumen into the cell thru the brush border
SGLT transporter
what type of secondary active reabsorption transporter lets glucose and sodium be co-transported down their electrical gradient
sodium-hydrogen exchanger
there is secondary active reabsorption via what counter transporter
proximal tubule
what is made up of highly metabolic cells w extensive brush border where 65% of sodium is reabsorbed, also Cl HCO3 K H2O glucose aa, and secretes H+ organic acids bases
descending loop
what part of the loop of henle is highly permeable to water
ascending loop
what part of the loop of henle is impermeable to water and the thick part reabsorbs 25% sodium, also Cl K HCO3 Mg and secretes H+
furosemide (lasix)
what is a loop diuretic in the distal part of the loop of henle that inhibits the 1-sodium, 2-chloride, K+ cotransporter
furosemide
the end result of what diuretic is that it binds to the chloride receptor and causes sodium, potassium, and chloride, to be excreted causing low amounts
thiazide diuretic
what is a diuretic that works in the distal tubule by binding to the chloride of the NaCl cotransporter and blocks it so inhibits NaCl reabsorption
early distal tubule
what reabsorbs sodium, chloride, calcium, magnesium, but is virtually impermeable to water and urea
late distal tubule and collecting tubule
what are made of two distinct cell types the principal and intercalated cells
prinicpal cells
what cells are in the late distal tubule and collecting tubule and reabsorb sodium from the lumen and secrete potassium ions into the lumen
intercalated cells
what cells are in the late distal tubule and collecting tubule and reabsorb potassium and bicarb ions from the lumen and secrete hydrogen ions into the lumen
aldosterone antagonists (spironolactone and eplerenone)
what compete with aldosterone for binding sites in the late distal tubule and collecting tubular cells and therefore inhibit the effects of aldosterone to stimulate sodium reabsorption and potassium secretion.
sodium channel blockers (amiloridde and triamterene)
what directly inhibit the entry of sodium into the sodium channels in the late distal and collecting tubular cells
medullary collecting ducts
what actively reabsorb sodium and secrete hydrogen ions and are permeable to urea, which is reabsorbed in these tubular segments. The reabsorption of water here is controlled by the concentration of ADH
aldosterone
what is made in the adrenal cortex in response to angiotensin II or hyperkalemia
aldosterone
what acts in principal cells of the collecting duct to stim sodium-potassium pump
conn's syndrome
what is when an adrenal tumor overproduces aldosterone, causes hypertension and hypokalemia
ADH
what increases the water perm of the distal tubule, collecting tubule, and collecting duct epithelial, helps the body to conserve water in cricumstances such as dehydration
ADH
w/o what the permeability of the distal tubule and collecting ducts to water is low, causing the kidney to excrete large amounts of dilute urine
V2 receptors
ADH binds to specific what in the late distal tubules, collecting tubules, and collecting ducts, inc the formation of cAMP and activating protein kinases, the molecules of AQP-2 cluster together and fuse w the cell memb by exocytosis to form water channels that permit rapid diffusion of water thru the cells
ANP
Specific cells of the cardiac atria, when distended because of plasma volume expansion, secrete what that inhibits the reabsorption of sodium and water by the renal tubules, especially in the collecting ducts.
ANP
what also inhibits renin secretion and therefore angiotensin II formation, which in turn reduces renal tubular reabsorption. This dec sodium and water reabsorption increases urinary excretion, which helps to return blood volume back toward normal.
ANP
what levels are elevated in congestive heart failure when the cardiac atria are stretched bc of impaired pumping of the ventricles. The inc levels helps to attenuate sodium and water retention in heart failure. Brain Naturetic peptide (BNP) is another serum marker for CHF
sympathetic system
activation of what if severe, can decrease sodium and water excretion by constricting the renal arterioles, thereby reducing GFR. Even low levels dec sodium and water excretion by inc sodium reabsorption in proximal tubule, thick ascending limb of the loop of Henle, and maybe more distal parts of renal tubule. occurs by activation of α-adrenergic receptors on the renal tubular epithelial cells.also inc renin release and angiotensin II formation, which adds to overall effect to inc tubular reabsorption and dec renal excretion of sodium