Term
sodium
-it gets pumped out via primary active transport using the Na/K+ pump to keep the sodium low in the cell |
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Definition
| what drives the transport of all other solutes in the nephron? |
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Term
sodium is transported into the cell using secondary active transport via the gradient created by the Na/K+ pump
it pumps other stuff into the cell along with it |
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Definition
| how does sodium get into tubular epithelial cells to begin with? |
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Term
glucose and amino acids
Cl- is cotransported paracellularly |
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Definition
| what substances are transported symport with Na+ in tubular cells? |
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Term
| H+, this is important for acid/base balance |
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Definition
| What substances are transported antiport with Na+ in tubular cells? |
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Term
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Definition
| which moves things quicker through a cell: facilitated diffusion or simple diffusion? |
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Term
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Definition
| the plasma CONCENTRATION at which transport maximum is exceeded in some nephrons. This is determined by the transporte maximum of the whole kidney |
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Term
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Definition
| when ions travel through the paracellular route is it active or passive transport? |
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Term
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Definition
| the maximum RATE or reabsorbtion of a substance |
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Term
usually threshold is met before the transport maximum is reached due to some nephrons having different Tmax's
basically some nephrons will start spilling glucose or whatever into the urine before the others have maxed out so the max concentration (threshold) is met |
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Definition
| is threshold higher or lower than transport maximum? |
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Term
| no, normally the filtered glucose load is reabsorbed |
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Definition
| does the kidney play a role in regulating blood glucose levels? |
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Term
| yes, because the transport maximum of phosphate is altered by dietary PO4- and PTH |
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Definition
| does the kidney regulate phosphate reabsorbtion? |
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Term
| paracellularly, the Na+ diffuses due to a concentration gradient then Cl- follows due to an electrochemical (& concentration) gradient |
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Definition
| how is Cl- cotransported with Na+? |
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Term
| to maximize SA for reabsorbtion (it does ~65% of the reabsorbtion) |
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Definition
| why does the proximal tubule have a brush border? |
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Term
| Na+, Cl-, HCO3-, K+, H2O, glucose, aa's |
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Definition
| what is reabsorbed in the proximal tubule? |
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Term
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Definition
| what is secreted into the lumen of the PCT? |
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Term
| the relative reabsorption of solutes compared to water |
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Definition
| what does the concentration of solutes in different parts of the tubule depend on? |
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Term
| the descending and ascending thin segments |
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Definition
| which part(s) of the LoH have thin epithelium with no brush border, few mitochondria, and low metabolic activity? |
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Term
thick ascending segment
this part is impermeable to water but has the tri-pump in it |
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Definition
| which part(s) of the LoH have thick epithelial cells with hight metabolic activity to facilitate resorption of Na, Cl, K+? |
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Term
the thin descending LoH is VERY permeable to water
the thick ascending loop is impermeable to water (so the filtrate is hypoosmotic here) |
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Definition
| what parts of the LoH are very permeable to water? which is not permeable? |
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Term
| the tri-pump in the thick ascending LoH |
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Definition
| what is the target of loop diuretics? |
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Term
| 1 Na, 2 Cl, and 1 K+ are all actively cotransported into the tubular cell from the lumen |
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Definition
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Term
it contains the macula densa, otherwise...
it is functionally similar to the thick ascending loop: impermeable to water and actively reabsorbs Na+, Cl-, K+, and Mg++ |
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Definition
| what is special about the early distal tubule? |
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Term
| early distal tubule. This is targeted(blocked) by thiazide diuretics, which inhibit sodium reabsorption |
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Definition
| where are sodium and chloride actively cotransported(symport) into tubular cells? what drugs target this? |
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Term
| not permeable to water, not very permeable to urea |
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Definition
| describe the characteristics of the early distal tubule |
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Term
permeability of H2O depends on ADH(argenine vasopressin)
also not very permeable to urea |
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Definition
| describe the characteristics of the late distal tubule/collecting tubule? |
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Term
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Definition
| what "special cells" in the late distal tubule and collecting tubules respond to aldosterone? |
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Term
| principal cells, passive sodium absorption and K+ secretion |
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Definition
| what cells are in the cortical collecting tubule that have 2 diuretic targets? what is special about them? |
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Term
| the sodium channels in the cortical collecting tubule (principal cells) |
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Definition
| what is the target of Na+ channel blockers such as amiloride and triamterene? |
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Term
they block aldosterone which prevents sodium retention and K+ secretion
overall get a sodium loss |
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Definition
| what is the target of aldosterone antagonists such as spironolactone and eplerenone? |
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Term
| cortical collecting tubule, have an H+/K+ ATPase pump and an H+ ATPase pump |
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Definition
| where are the intercalated cells located, and what is special about them? |
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Term
absorbed: HCO3-, Na+, Cl-, Urea, H2O(with ADH)
secreted: H+ |
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Definition
| what is reabsorbed in the medullary collecting tubules? what is secreted? |
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Term
2500mg (7.4 mg table salt, 1.25 tsp)
low sodium: 1500mg (3.5g table salt) |
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Definition
| what is the USDA reccomendation of sodium intake? what is a low sodium diet? |
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Term
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Definition
| how much salt is excreted per day if 8.8 g table salt is consumed? |
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Term
1) 65% in the PCT
2) 25% in the thick ascending loop (tri pump)
3) 7% in the DCT
4) 2.4% in the collecting tubule |
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Definition
| where is most of the sodium reabsorbed in the nephron? |
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Term
| peritubular capillary physical forces, especially oncotic pressure |
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Definition
| what is once of the main things regulating glomerulotubular balance? |
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Term
1)aldosterone
2)angiotensin 2
3)ADH
4)naturiuretic hormones (ANF)
5) parathyroid hormones |
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Definition
| what are the hormones that regulate tubular reabsorption? |
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Term
1) glomerulotubular balance
2) hormones
3) sympathetic nervous system
4) arterial pressure |
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Definition
| what 4 things regulate tubular reabsorption? |
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Term
| tubular reabsorption - it does not remain constant, instead it changes to maintain H2O/electrolye balance |
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Definition
| what increases with filtered load that has to do with glomerulotubular balance? |
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Term
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Definition
| what is the equation for tubular (filtered) load? |
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Term
| it maintains the ECFV (extracellular fluid volume) |
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Definition
| why is tubular reabsorption so important? |
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Term
the plasma lost 20% of the H2O in the glomurulus, so the protein concetration increases by 25% relatively, all the oposing forces (like colloid osmotic pressure)
you want to keep the water in the capillaries for the most part, so downstream the "concentrated" plasma picks water back up from the renal tubules |
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Definition
| why is there peritubular capillary reabsorbtion? |
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Term
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Definition
| to optimize GFR you want ___ glomerular capillary hydrostatic pressure and ___ interstitial pressure |
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Term
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Definition
| to optimize resorption in the peritubular capillaries, you want ___ interstitial hydrostatic pressure, __ capillary hydristatic pressure, and ___ capillary colloid osmotic pressure with ___ intersitial capillary colloid osmotic pressure |
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