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30 Cards in this Set
- Front
- Back
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Renal Blood Flow is dependent on:
A.Juxtaglomerular apparatus B.[Na+] at macula densa C.Afferent vasodilatation D.Arterial pressure E. Efferent vasoconstriction |
d. Broadly true – DEPENDENCE ???, but autoregulated 70 – 170 mmHg
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Factors not affecting Renal Blood Flow:
A. SNS B. Sodium flow past macula densa C.Afferent arteriolar vasodilation D.Arterial Pressure E.Efferent arteriolar vasoconstriction |
d.No, only at extremes of pressure (outside autoregulatory range) – between 80-180mmHg
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Renal Blood Flow:
a. 600 ml/min per kidney b. Is directly measured by infusing PAH c. Is increased by SNS tone |
a. about 1200 ml/minute total or 25% cardiac output
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Renal Blood Flow:
A.Greater per unit mass than cerebral blood flow B.greater in the medulla compared to the cortex C.Is closely related to tubular sodium reabsorption D.Only sympathetically mediated E.Some noradrenergic endings on JG complex and tubules |
A. Correct (Brain 50ml/min/100g) versus Kidneys 360 ml/min/100g
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Which has the greatest renal clearance?
A. PAH B. Glucose C. Urea D. Inulin E. Water |
ANSWER A
PAH (almost completely cleared - used to measure renal blood flow) |
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The ascending limb of the thick loop of Henle:
A. Impermeable to Na B. Active transport of K into the lumen C. Active transport of Cl out of the lumen D. Active transport of Na into the lumen E. Hypotonic at the top F. Actively transports water |
C. Active transport of Cl out of lumen (Na/K/2Cl transporter)
E. Henle's Loop absorbs more solute than water as a whole so the tubular fluid is hypoosmotic at exit |
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Regarding glucose handling in the kidney:
A. Reuptake is passive B. Tm is the same for all nephrons C. D-glucose more rapidly reabsorbed than L-glucose D. Reabsorption is inversely proportional to lipid solubility E. |
C. Yes. SGLT2 transporter has increased affinity for D-glucose isomer compared with L-glucose.
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Water filtration by the kidney:
A. 180 L/hr B. 125 ml/min C. Up to 95% Reabsorbed D. Most drugs have MW<600 and are freely filtered |
B. 125 ml/min
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Absorption of Urea takes place in:
A. Proximal Convoluted Tubule B. Distal Convoluted Tubule C. Ascending loop of Henle D. Juxtaglomerular apparatus E. Principle Cell |
ANSWER A. PCT (about half is reabsorbed in PCT)
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Glomerular capillary permeability is:
A. Less than in ordinary capillaries B. 50 times that of skeletal muscle capillaries C. |
B. 50 times that of skeletal muscle capillaries
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Which one of the following is not involved in the regulation of GFR?
A. Juxtaglomerular apparatus B. arterial pressure C. efferent arteriolar tone D. Na content in distal tubule E. afferent arteriolar tone |
B. No, autoregulation maintains GFR within normal limits, although pressure diuresis may occur
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With Regards to GFR
A. Autoregulation maintains Flow B. Afferent arteriolar pressure is the driving force C. Is equal for cationic and anionic molecules D. All cross if < 8 nm diameter E. |
A. Correct
B. ??? |
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The permability of glomerular capillaries:
A. Equals that of other capillaries B. Is much less than other capillaries C. Is equal for cationic/anionic molecules of equal size D. Approaches 100% for neutral molecules of 8 nm diameter E. Is about 50 times that of skeletal muscle capillaries |
E. Correct
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Regarding osmolality if urine:
A.maximum urine osmolality is 1200 mOsm/L B. Minimum urine osmolality is 100 mOsm/L C. Minimum urine osmolality is 20 mOsm/L |
A. Correct (or even up to 1400 mOsm/L)
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Significant tubular reabsorption does not occur with:
A. Phosphate B. Creatinine C. Urea D. Sulphate |
B. Creatinine
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Which of the following is involved in regulation of GFR?
A. Juxtaglomerular Apparatus B. Afferent arteriolar tone C. Efferent arteriolar tone D. Chloride transport at the macula densa E. All of the above |
E. All of the above
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The formula for GFR is:
A. GFR = Kf (Pg-Pb+Og-Ob) B. GFR = Kf(Pg-Pb-Og+Ob) C. GFR = Kf(Pg+Pb-Og+Ob) D. GFR =Kf(Pg+Pb-Og-Ob) E. GFR = Kf(Pg-Pb-Og-Ob) (Comment: HP is hydrostatic pressure, OP is oncotic pressure, G is glomerulus, B is Bowman’s capsule) |
B. GFR = Kf(Pg-Pb-Og+Ob)
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The effect of PTH on the kidney is to:
A. Increase Ca excretion and increase phosphate excretion B.Increase Ca excretion and decrease phosphate excretion C.Decrease Ca excretion and increase phosphate excretion D.Decrease Ca excretion and decrease phosphate excretion E.None of the above |
C.Decrease Ca excretion and increase phosphate excretion
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Maximal water reabsorption with ADH is?
A. 93% B. 94% C. 99% D. 99.4% E. 99.9% |
D.99.4%
99.9% would be too much to excrete the minimum solute/day so can never be correct |
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Resistance to renal blood flow is chiefly determined by?
A. Renal artery B. Afferent & efferent arterioles C. Interlobular & arcuate arteries D. Peritubular capillaries |
B. Afferent & efferent arterioles
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Tubuloglomerular feedback:
A. Increased solute delivery to macula densa causes decreased GFR B. Is a dull subject best studied after several beers C. Relates to regulation of Magnesium D. Got we'll be pissed after exams |
A. Increased solute delivery to macula densa causes decreased GFR
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For renal clearance of a substance to exceed inulin's?
A. There must be an increase in GFR B. The substance must be secreted by the PT or DT C. The subtance must have a lower MW than inulin D. The substance must be actively reabsorbed |
B. The substance must be secreted by the PT or DT
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If a substance with the same plasma concentration is found in the urine at higher concentration than Inulin:
A. It must be filtered more B. It must be secreted C. It must be reabsorbed less D. It must be positively charged E. It must be negatively charged |
B. It must be secreted
Inulin is freely filtered substance that is not reabsorbed nor actively secreted, making this useful for calculation of glomerular filration rate (GFR). i.e. The renal clearance of inulin equals GFR. |
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Water excretion by the kidney is due to:
A. Osmosis B. Active transport into the lumen C. Passive secretion in the collecting tubules D. Solvent drag E. Facilitated diffusion F. Paracellular movement |
A. Osmosis
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Angiotensin 2 causes:
A. Increases proximal tubular reabsorption of Na & H2O and increases secretion of K+ B. Increases distal tubular reabsorption of Na & H2O & decreases secretion of K+ C. Decreases distal tubular reabsorption of Na & H2O D. Increases excretion of Na & H2O |
A. Increases proximal tubular reabsorption of Na & H2O & increases secretion of K+ – Correct (the effect on K is a distal tubule event). Ganong 22nd Ed page 723
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Glomerulotubular balance:
A. Involves afferent arteriole feedback loop B. Involves efferent arteriole feedback loop C. Juxtaglomerular complex D. Ability to increase tubular absorption in response to an increase in filtered load E. None of the above F. Tubular resorption is matched to GFR |
D. Ability to increase tubular absorption in response to an increase in filtered load
Glomerulotubular balance refers to the kidney's ability to increase the reabsorption of solutes (predominantly in the proximal tubule) in response to an increase in GFR. This ensures that the proportion of solute reabsorbed remains constant. D is the best answer, but if F appeared in the absence of D it is also correct in that a constant proportion means that it is matched |
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The kidneys produce:
A. Erythropoeitin B. ADH C. Angiontensin 2 D. ANP E. Cholecalciferol |
A. Erythropoeitin
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Renal sympathetic nervous stimulation:
A. Causes increased Na reabsorption from the PT B. Inhibits Renin release C. Increased GFR D. Vasodilation of efferent arteriole E. Mesangial cell dilation |
Answer A: Renal SNS activity causes a graded response
1. incr sensitivity of JG cells to non-neural stim for renin release (B1) 2. incr renin secretion by direct affect on JG cells (B1) 3. incr Na resorption by direct NA action on renal tubular cells (PCT, DCT, asc LOH) via A1 & B1 4. renal vasoconstriction efferent then afferent arterioles RBF > GFR (thus FF incr) 5. reduces GFR by causing mesangial cell contraction |
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Water Reabsorption by the kidney:
A. 90% in PT B. 60% in DT C. By active transport D. None of the above |
D. None of the Above
• Most texts quote 65% of H2O resorption in PCT, 10% reabsorbed in the Descending thin limb of Henle, and the remaining proportion in the collecting duct system (5% during water loading, >24% during dehydration). • The DCT is impermeable to H2O • No H2O is actively transported |
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GFR:
A. Is independent of the size of the capillary bed B. Depends only on the hydrostatic and osmotic pressure differences across the capillary C. Is determined by the same forces governing filtration across all other capillaries D. Depends only on the permeability of the capillary E. Requires active transport |
C. Is determined by the same forces governing filtration across all other capillaries - Correct
GFR: • decreases with decrease in the size of the capillary bed (decrease in filtration surface area)- so A is wrong • depends on capillary permeability and surface area, not just the net pressure gradient - so B is wrong • depends on factors other than the permeability of the capillary - see Starling's hypothesis - so D is wrong • No active transport is involved in (ultra)filtration - so E is wrong. |
