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The kidneys need to be functioning to produce _________ urine.
concentrated OR dilute (non-functioning-isosthenuria)
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The deeper you go into the medulla, ...
the more conc the interstitium gets
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As UF moves down the descending loop of henle, water moves __________ from _________ to _________.
passively; lumen; conc interstitium
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Concentration of UF _________ as it moves down the loop of henle.
increases
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The ascending loop of henle is impermeable to _________; it has the _________ to actively pump _________ from ________ to _________.
water; Na+K+2Cl- pump; sodium; the lumen; the interstitium
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Concentration of UF __________ as it moves up the loop of henle.
decreases (water trapped, sodium actively pumped out)
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What 2 pathways can be taken to alter urine conc in the cortical collecting tubule?
impermeable to water, pump out sodium, dilute urine; open water channels for water to passively leave the lumen to conc interstitium, concentrate urine
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With the countercurrent multiplier, UF enters the proximal tubule--> in ascending LoH, _____________--> more UF enters proximal tubule--> _____________--> ongoing to produce ____________
solutes actively pumped to interstitium, concentrating it; water leaves proximal tubule, pulled into conc interstitium; electrochemical concentrating gradient
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The vasa recta travels alongside the _________.
descending and ascending LoH
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The vasa recta has _______ flow; flow that is too _______ may cause...
sluggish; rapid; wash out of the solutes and decrease concentrating ability.
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As blood goes down the vasa recta, ________ from the interstitium diffuses into the blood and _________ diffuses out.
solutes; water
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As blood goes up the vasa recta, ________ enters the blood and ________ exit it.
water; solutes
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Why is urea important to urine concentration?
uea provides half the concentration gradient; therefore, decreased urea--> decreased conc gradient--> decrease concentrating ability
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Urea is ________ at the glomerulus; it is _________ in the proximal tubule.
freely filtered; passively reabsorbed
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As water is reabsorbed from the cortical collecting duct, urea concentration __________; at the UF moves through the medullary collecting duct, urea moves into the _________ through urea transporters, helping to create the _________.
increases; interstitium; conc gradient
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How is urea from the medullary interstitium recycled?
interstitial urea diffuses into the thin loop of henle when urea conc is low--> urea is carried up the loop of henle and goes back through the system
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Give 3 examples of circumstances that may impair urine concentrating ability.
increased blood flow in vasa recta, decreased urea, hyponatremia
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ADH is made in the _________ of the _________.
supraoptic nucleus; hypothalamus
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Osmoreceptors in the brain are outside of the __________, making it easy for them to....
BBB; monitor blood osmolality.
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Stimuli for ADH release. (6)
osmoreceptors detect minor changes in blood osmolality, baroreceptors sence large changes in blood volume/pressure,nausea, pain, anxiety, morphine
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Effects of ADH. (5)
vasoconstriction, aquaporins inserted in luminal membrane of collecting duct, more water reabsorbed from lumen, increased urine SG, lower urine volume
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When ADH is absent... (4)
no aquaporins, waters trapped in lumen of collecting duct, low urine SG, high urine volume
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Excess ADH causes __________.
volume retention
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Low ADH causes __(2)__.
dilute urine, hypernatremia
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Diuretic inhibit _________ in the renal tubule, leading to...
sodium reabsorption; solute and water loss.
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What are the two classes of diuretics?
chemical diuretics (affect pumps), osmotic diuretics
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Furosemide is a __________; it works in the _________.
loop diuretic; loop of henle
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Furosemide is secreted by the _________ and reaches the _______ side of the ________ by tubular flow; it binds to ____________, and inhibits it.
proximal tubule; luminal; loop of henle;Cl- site of Na+K+Cl- pump
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Furosemide keeps __(4)__ in the _______.
Na+, K+, Cl-, water; tubular lumen
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Side effects of furosemide. (4)
hypokalemia, hypovolemia, metabolic alkalosis, ototoxicity (deafness)
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Thiazide diuretics impair the __________ in the __________.
Na+Cl- cotransporter; distal tubule
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Thiazide diuretics are considered ___________, meaning minimal drug is needed to reach maximal effect.
low ceiling
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Thiazide diuretics are used to ___________ in ___________ patients.
decrease excretion of calcium; stone-forming
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Spironolactone is a ___________; it works by preventing...
aldosterone antagonist; aldosterone from inserting Na+ and K+ channels, preventing the reabsorption of Na+ and secretion of K+
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Substances that are freely filtered at the glomerulus and increase the osmolality of the ultrafiltrate.
osmotic diuretics
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What kind of diuretic is used to dilate the tubules and expels casts?
osmotic diuretics
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How do you adjust the drug dosage of a drug with a long half-life and conc does not have to be sustained to continue having an effect?
lengthen dosing interval; new interval= old interval (patient cre/normal cre)
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How do you adjust the dosage of a drug for a time-dependent drug and when the minimum drug conc is important?
decrease the dose; new dose= old dose (normal cre/patient cre)
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What substances are excreted? (5)
K+, H+, ammonium, urate, organic acids and bases
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The vast majority of potassium is located ___________.
inside cells
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Factors that shift K+ into cells. (2)
insuline, aldosterone
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Diseases that shift K+ out of cells. (2)
diabetes, addison's
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Hyperkalemia causes ________________.
life-threatening arrhythmias
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The principal cells reabsorb ___________ and secrete __________ under the influence of __________.
sodium; potassium; aldosterone
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Factors controlling K+ secretion. (3)
activity of Na+K+ATPase pump, electrochemical gradient from blood to lumen, permeability of luminal membrane to K+
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Intercalated type A cells __________ K+.
reabsorb
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Lack of aldosterone, _________, can cause severe _________.
addison's disease; hyperkalemia
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An increase in K+ secretion is due to... (3)
increase in extracellular [K+], increased aldosterone, increased distal tubular flow
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An increase in serum potassium conc increases excretion in 3 ways:
increase in activity of the Na+K+ATPase pump, increased interstitial conc compared to inside cells, direct stimulation of aldosterone secretion
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Increased aldosterone increases the ________________.
activity of the Na+K+ATPase pump
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Aldosterone _______ K+; K+ _________ aldosterone.
decreases; increases
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When flow through the distal tubule is relatively slow, K+ _________ in the _________; the gradient b/w the cell interior and lumen diminishes, slowing ____________.
accumulates; lumen; K+ leaking into the lumen
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When flow through the distal tubule is fast, K+ is continuously ____________, maintaining a ____________.
washed downstream; large gradient for diffusion
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Acute acidosis _______ the ____________, thus __________ K+ secretion.
slows; Na+K+ATPase pump; decreasing
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K+ is required for...
repolarization of the membrane of an excitable cells.
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With hypokalemia, cell membranes are ___________; therefore, ______ K+ leaking should take place to reach threshold and generate an action potential; this can cause __________.
hyperpolarized; more; weakness
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With hyperkalemia, initially the cell is __________, but with more severe hyperkalemia, _________ potential is less than _________ potential, making the cells unable to ________.
hyperexcitable; resting; threshold; repolarize
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Organic acids and bases are secreted by...
non-specific acid and base carriers in the proximal tubule.
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What 2 defects in Dalmatians make them susceptible to urate stones?
decrease proximal tubule uric acid reabsorption, increase distal tubular urate secretion----> urolithiasis
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