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43 Cards in this Set
- Front
- Back
What is the function of the nephron?
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To filter blood which then passes as fluid into a series of tubules.
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Tubules reabsorb most of the constituents of the fluid remaining after blood is filtered to produce what? Where is this sent?
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Urine, which is passed into the renal pelvis.
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T or F: The renal artery receives 25% of cardiac output.
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True.
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The renal artery takes blood to afferent arterioles. How so?
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Via interbolar and arcuate arteries.
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What are the 2 types of nephrons?
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1) Cortical nephron
-glomeruli originate in outer section of cortex and loop of Henle descends into the outer medulla 2) Juxtamedullary nephron -glomeruli originate in the inner cortex and loop of Henle descends into the inner medulla. |
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Which of the 2 types of nephrons plays a central role in production of concentrated urine?
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Juxtamedullary.
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What surrounds the glomerulus?
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Bowman's capsule.
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Of which of the following 4 items do fenestrated capillaries allow filttration of into Bowman's capsule? Plasma, blood cells, platelets, and dissolved solutes.
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Plasma & dissolved solutes
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What are the 3 barries plasma passes through during glomerular filtration?
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1) Capillary fenestrations
2) Glomerular basement membrane 3) Inner layer of Bowman's capsule consisting of podocytes |
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Podocytes wrap around capillaries with thousands of cytoplasmic extensions know as ______. (Slits between these extensions act as a barrier during glomerular filtration.)
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Pedicels.
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What is the fluid entering Bowman's capsule known as? What does this fluid consists of?
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Filtrate; consists of plasma and a small amount of plasma protein (albumin)
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T or F: Glomerular Filtration Rate (GFR) is the volume of filtrate produced by both kidneys per day.
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False. Glomerular Filtration Rate (GFR) is the volume of filtrate produced by both kidneys per minute.
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T or F: The total blood volume (5.5L) is filtered every hour.
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False. The total blood volume is filtered every 40 minutes.
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T or F: Vasoconstriction causes an increase in GFR.
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False: Vasoconstriction causes a reduction in GFR. Vasodilation causes an increase in GFR.
(more blood = more filtration) |
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T or F: The kidneys maintain a constant GFR regardless of changes in MAP.
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True
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Explain the myogenic response of the afferent arterioles.
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BP increases -->reflex constriction of a.a.
BP decreases--> reflex dilation of afferent arterioles |
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T or F: The tuboglomerular feedback system involves regulation of NaCl concentration levels.
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True.
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T or F: Macula Densa are the specialized cells in the descending loop of Henle which detect increases in [NaCl] of tubular fluid
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False. Macula Densa are the specialized cells in the ASCENDING loop of Henle which detect increases in [NaCl] of the tubular fluid.
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What do macula densa do in repsonse to high levels of NaCl in the tubular fluid?
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Release ATP, which triggers contraction of afferent arterioles...thereby reducing GFR.
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How is GFR regulated 'externally'?
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Renal sympathetic nerves release noradrenaline, which triggers constriction of afferent arterioles. A decreased urine production prevents reduction in blood vol. and BP.
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T or F: 99% of filtrate is reabsorbed in the nephron and is returned to the vasculature.
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True
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T or F: Reabsorption of the filtrate is carried out by epithelial cells lining the inner wall of the nephron.
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True.
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Reabsorption of ___ is the driving force for reabsorption of other filtrate constituents.
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Na+
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How is Na+ reabsorbed in the proximal tubule? (What type of transport?)
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Active transport;
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The energy released during movement of Na+ down a gradient also drives reabsorption of other molecules like glucose and amino acids. What type of transport is this?
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Co-transport.
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What molecules follow the movement of Na+, glucose, and amino acids? (Using passive transport)
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Cl- and H2O
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What does glomerular filtrate consist of?
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Plasma minus plasma proteins
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T or F: Glomerular filtrate is isosmotic with plasma.
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True. Both = 300 mOsm.
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Because salt and water transport are ______, filtrate exiting the PT is still isosomtic with plasma and is 300 mOsm.
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coupled
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T or F: The loop of Henle determines the osmolarity of tubular fluid using countercurrent multiplier system (CMS).
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False. The loop of Henle determines the osmolarity of URINE using the CMS.
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Briefly describe the countercurrent multiplier system.
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Dehydration- low vol, [ ]ed urine is produced
Excess hydration- high volume, dilute urine is produced |
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Where is the site of urine concentration determination?
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The collecting duct.
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T or F: The CMS achieves the need to keep the osmolarity of interstitial fluid high and the osmolarity of tubular fluid to be low.
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True.
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T or F: The absorption of NaCl and H20 is coupled.
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False. Only the transport of these two molecules is coupled. Because there are no aquarporins in the ascending limb of the loop of Henle, there is NO H20 TRANSPORT.
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T or F: After reabsorption, the tubular filtrate is "salty" and the medulla is diltue.
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False. After Na+ reasborption, the tubular fluid becomes dilute and the MEDULLA becomes "salty".
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T or F: Vasa Recta are long blood vessels that parallel the loop of Henle
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True
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T or F: Fluid leaving the collecting duct is urine.
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True/
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As the abundance of AQP2 increases, the rate of water absorption decreases.
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False as AWP2 increases, H20 absorption also increases.
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T or F: As urine volume increases,it's osmolarity decreases.
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True.
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T or F: ADH triggers the insertion of AQ2 into the apical membrane to increase reabsorption.
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True.
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T or F: Aldosterone stimulates an increase in Na+ reabsorption.
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True.
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T or F: Alkalosis is a decrease in pH.
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False. Acidosis is a drop in pH. Alkalosis is an increase in pH.
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T or F: Glycosuria is a sign of diabetes mellitus.
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True. Glucose should not normally exist in the urine.
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