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60 Cards in this Set
- Front
- Back
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in the proximal tubule how is Na reabsorbed
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countertransport with H+ (Na+/H+ exchange)
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what is the mechanism for Na reabsorption in the thick ascending limb
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Na, K, 2Cl cotransport
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where is Na and Cl cotransported
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early distal convoluted tubule
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where is the only place that Na is brought in by itself
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late distal convoluted tubules
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does water reabsorption require energy
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always passive
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does water reabsorption occur transcellularly or paracellularly
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both!
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what is chloride reabsorption always linked to either directly or indirectly
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Na
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what portion of the loop of henle is permeable to water
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descending
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what is the descending limb of henle impermeable to
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na and cl
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what is the ascending limb of the henle impermeable to
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water
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what occurs at the thick segment of the ascending loop of henle
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active na, k, 2cl cotransport
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what occurs at thin segment of the ascending loop of henle
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passive nacl reabsorption
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what is the site of physiological control of salt and water
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collecting duct
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what does aldosterone do in collecting duct
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stimulates na reabsorption k secretion and h secretion
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what does atrial naturiuretic peptide do in the collecting duct
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inhibits na reabsorption
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what does the antidiuretic hormone do in the collecting duct
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stimulate water reabsorption
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how does aldosterone increase the na reabsorption in the collecting duct
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increases na channels in the luminal membrane and na k atpase in basolateral membrane
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do you see effects of aldosterone immediately and why or why not
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no, it is a steroid. it works via making the proteins needed for na channels
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in dehydrated individuals what occurs at the collecting duct
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it is highly water permeable and water is reabsorbed and low volume urine is excreted
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how does ADH increase water permeability in the late distal tubule, collecting duct
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via cAMP it increases the amounts of aquaporins on the luminal side
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what portion of the kidney has a greater solute concentration
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the inner medulla
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what is the countercurrent multiplier mechanism
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concentrates solute in the medullary interstitium; enables kidneys to conserve water during periods of dehydration
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what are the 3 components of the countercurrent multiplier
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vasa recta, loop of henle and collecting duct
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what is action of the vasa recta in the countercurrent multiplier
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exchanger
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what is action of the loop of henle in the countercurrent multiplier
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multiplier
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what is action of the collecting duct in the countercurrent multiplier
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osmotic equilibrator
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where is urea concentrated in the nephron by 50%
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pct
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what promotes the urea absorption from the inner medullary collecting duct
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adh
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what makes the collects duct epithelium highly permeable to water
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adh
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where is the highest osmolarity of the blood?
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vasa recta
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what is the minimum urine excretion to eliminate wastes per day
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500 mL
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if urine osmolarity is less than plasma osmolarity then clearance of water is positive or negative
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positive
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when clearance of water is positive then water is retained or cleared
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cleared
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what was the clearance equation
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u*v/p
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what does the vasa recta maintain
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the solute gradient
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angiotensin 2 stimulates the efferent or afferent constriction
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efferent
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what happens to adh in response to a2
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secretion from posterior pit
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what happens to aldo in response to a2
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secretion from adrenal cortex
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where does a2 cause na reabsorption
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proximal tubule
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what is aldosterone's action in the collecting duct
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sodium reabsorption
k secretion h secretion |
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what 3 factors control aldo secretion
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increased k conc
increased acth conc increased angiotensin II conc |
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what does anp do to gfr
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increase
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how does anp act : afferent and efferent
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dilates afferent
constricts efferent |
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what does anp do to na
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inhibits reabsorption
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what does anp do to renin
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suppresses it
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what does anp do to aldo secretion
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suppresses it
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what does anp do systemically
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vasodilate
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what does anp do to adh secretion
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suppress it
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where does anp come from
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cardiac atria
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where is urodilatin secreted
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in the dct and collecting duct
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what does urodilatin do systemically
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no effect
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what does intrarenal prostaglandins do to na
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they suppress reabsorption in the thick ascending limb of cortical collecting duct and therefore increase na excretion
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what does intrarenal prostaglandins to gfr
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dilate renal arterioles
increase gfr |
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what controls the adh secretion
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aortic baroreceptors -> supraoptic nucleus
hepatic osmoreceptors -> hypothalamic osmoreceptors |
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what happens to adh in response to plasma osmolality
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increases linear relationship
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what happens to adh in response to blood volume depletion
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small changes do not change adh but large changes in volume cause a dramatic adh
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if a person has a 15% decrease in blood volume/pressure and has low plasma osmolality, what is the response of adh
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it is steeper than normal it responds faster
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if a person has a 15% increase in blood volume/pressure and has high plasma osmolality, what is the response of adh
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there is a volume expansion, it responds much slower than normal
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what is the renal response to increase nacl intake
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decreased renin and therefore increased nacl excretion
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hemorrhage leading to decreased arterial blood pressure, what is the renal response
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decreased baroreceptor firing, and increased adh secretion, leading to h2o reabsorption from collecting duct and thus the maintenance of bp
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