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Question 1
Incorrect
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The interstitium of the kidney is most hypertonic in the:
Your Answer: Juxtaglomerular apparatus
Correct Answer: Papillary tip of the medulla
Explanation:The medullary interstitium is the tissue surrounding the loop of Henle in the renal medulla. It functions in renal water reabsorption by building up a high hypertonicity, which draws water out of the thin descending limb of the loop of Henle and the collecting duct system. This hypertonicity, in turn, is created by an efflux of urea from the inner medullary collecting duct.
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This question is part of the following fields:
- Medicine
- Renal
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Question 2
Incorrect
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In a 70 kg male, the approximate volumes (litres) of water in the different compartments mentioned (intracellular, interstitial, vascular) are:
Your Answer: 32l, 6l, 4l
Correct Answer: 28l, 14l, 3.5l
Explanation:In a 70kg male, approximately 60% (42 L) of the total body weight is composed of water divided proportionally in the following compartments:Intracellular fluid (ICF) – Around 67% (28 L) of total body water.Extracellular fluid (ECF) – Approximately 33% (14 L) of the total body fluid. The fluid in the intravascular compartment is about 3 L and is generally about 25% of the volume of ECF.
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This question is part of the following fields:
- Medicine
- Renal
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Question 3
Correct
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Which segment of the nephron is impermeable to water?
Your Answer: Ascending limb of Henle
Explanation:Considerable differences aid in distinguishing the descending and ascending limbs of the loop of Henle. The descending limb is permeable to water and noticeably less permeable to salt, and thus only indirectly contributes to the concentration of the interstitium. Unlike the descending limb, the thin ascending limb is impermeable to water, a critical feature of the counter current exchange mechanism employed by the loop.
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This question is part of the following fields:
- Medicine
- Renal
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Question 4
Correct
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The ENaC Transporter occurs in which part of the renal tubule?
Your Answer: Collecting duct
Explanation:The epithelial sodium channel (ENaC) is a membrane-bound ion channel that is selectively permeable to Na+ ions. It is involved primarily in the reabsorption of sodium ions at the collecting ducts of the kidney’s nephrons.
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This question is part of the following fields:
- Medicine
- Renal
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Question 5
Correct
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Question 6
Correct
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ANP and BNP in the circulation act on the kidney to?
Your Answer: Increase sodium excretion
Explanation:The physiologic actions of BNP are similar to those of ANP and include decrease in systemic vascular resistance and central venous pressure as well as an increase in natriuresis (sodium excretion). The net effect of these peptides is a decrease in blood pressure due to the decrease in systemic vascular resistance and, thus, afterload.
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This question is part of the following fields:
- Medicine
- Renal
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Question 7
Correct
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Renin is secreted by which of the following cells?
Your Answer: Juxtaglomerular cells
Explanation:The juxtaglomerular cells are cells in the kidney that synthesize, store, and secrete the enzyme renin. They are specialized smooth muscle cells mainly in the walls of the afferent arterioles, and some in the efferent arterioles, that deliver blood to the glomerulus.
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This question is part of the following fields:
- Medicine
- Renal
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Question 8
Incorrect
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In increasing order of concentration, the main anions in plasma are:
Your Answer: Cl-, Phosphates-, HCO3-, Proteins-
Correct Answer: Proteins-, HCO3-, Cl-,
Explanation:Anions are negatively charged ions and include: chloride Cl-, bicarbonate HCO3-, sulphate SO4-2, phosphate HPO4-2, and protein anions. Chloride it the most abundant anion followed by bicarbonate and then protein anions.
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This question is part of the following fields:
- Medicine
- Renal
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Question 9
Correct
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Where is angiotensinogen produced?
Your Answer: Liver
Explanation:Angiotensin is a peptide hormone that causes vasoconstriction and a subsequent increase in blood pressure. Angiotensin also stimulates the release of aldosterone from the adrenal cortex. Aldosterone promotes sodium retention in the distal nephron, in the kidney, which also drives blood pressure up. It is derived from the precursor molecule angiotensinogen, a serum globulin produced in the liver.
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This question is part of the following fields:
- Medicine
- Renal
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Question 10
Correct
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ADH causes?
Your Answer: Increased permeability of the collecting ducts to water
Explanation:Vasopressin (ADH) has three main effects:1. Increasing the water permeability of distal convoluted tubule and collecting duct cells in the kidney, thus allowing water reabsorption and excretion of more concentrated urine.2. Increasing permeability of the inner medullary portion of the collecting duct to urea by regulating the cell surface expression of urea transporters.3. Acute increase of sodium absorption across the ascending loop of Henle.
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This question is part of the following fields:
- Medicine
- Renal
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Question 11
Incorrect
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What is the most important determinant of ECF volume?
Your Answer: The amount of plasma filtered across the glomerular membrane
Correct Answer: The amount of sodium in the ECF
Explanation:The volume of the ECF is determined primarily by the total amount of osmotically active solute in the ECF. The composition of the ECF is discussed in Chapter 1. Because Na+ and Cl− are by far the most abundant osmotically active solutes in ECF, and because changes in Cl− are to a great extent secondary to changes in Na+, the amount of Na+ in the ECF is the most important determinant of ECF volume.
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This question is part of the following fields:
- Medicine
- Renal
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Question 12
Correct
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Where is the majority of Mg2+ absorbed?
Your Answer: Thick ascending limb of loop of Henle.
Explanation:Although the majority of the filtered magnesium is reabsorbed within the ascending loop of Henle, it is now recognized that the distal tubule also plays an important role in magnesium conservation.
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This question is part of the following fields:
- Medicine
- Renal
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Question 13
Correct
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An important enzyme in renal tissue responsible for the conversion of glutamine to glutamate and the subsequent production of NH4 is called?
Your Answer: Glutaminase
Explanation:Glutaminase catalyses the following reaction:Glutamine + H2O → Glutamate + NH3
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This question is part of the following fields:
- Medicine
- Renal
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Question 14
Correct
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How does the proximal convoluted tubule excrete H+?
Your Answer: Via Na+/H+ antiporter.
Explanation:H+ secretion from cells across the luminal membrane is mostly in exchange for Na+ ions, and to a small extent, through a proton ATPase. Secreted H+ react with filtered HC03- to form H2CO3.
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This question is part of the following fields:
- Medicine
- Renal
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Question 15
Correct
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An effect of aging on the kidney includes?
Your Answer: Decreased GFR
Explanation:The normal range of GFR, adjusted for body surface area, is 100 to 130 mL/min/1.73m2 in men and 90 to 120 ml/min/1.73m2 in women younger than the age of 40. After age 40, GFR decreases progressively with age, by about 0.4 mL/min to 1.2 mL/min per year.
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This question is part of the following fields:
- Medicine
- Renal
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Question 16
Incorrect
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Erythropoietin is synthesized by which cells of the nephron?
Your Answer: Glomerular epithelial cells
Correct Answer: Tubular interstitial cells
Explanation:Erythropoietin is produced by interstitial fibroblasts in the kidney in close association with peritubular capillary and proximal convoluted tubule. It is also produced in perisinusoidal cells in the liver. While liver production predominates in the fetal and perinatal period, renal production is predominant during adulthood.
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This question is part of the following fields:
- Medicine
- Renal
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Question 17
Correct
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Which of the following is a physiological effect of pregnancy on the kidney?
Your Answer: Decreased creatinine
Explanation:A pregnant woman may experience an increase in kidney and ureter size. The glomerular filtration rate (GFR) commonly increases by 50%, returning to normal around 20 weeks postpartum. Plasma sodium does not change because this is offset by the increase in GFR. There is decreased blood urea nitrogen (BUN) and creatinine and potentially glucosuria (due to saturated tubular reabsorption).
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This question is part of the following fields:
- Medicine
- Renal
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Question 18
Incorrect
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What is the function of the macula densa, located in the wall of the thick ascending limb?
Your Answer: Secrete renin.
Correct Answer: Tubuloglomerular feedback.
Explanation:Macula densa cells sense changes in sodium chloride level, and will trigger an autoregulatory response to increase or decrease reabsorption of ions and water to the blood (as needed) in order to alter blood volume and return blood pressure to normal. Tubuloglomerular feedback is one of several mechanisms the kidney uses to regulate glomerular filtration rate (GFR). It involves the concept of purinergic signalling, in which an increased distal tubular sodium chloride concentration causes a basolateral release of adenosine from the macula densa cells. This initiates a cascade of events that ultimately brings GFR to an appropriate level.
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This question is part of the following fields:
- Medicine
- Renal
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Question 19
Correct
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Amino acid reabsorption occurs most markedly in the?
Your Answer: Proximal convoluted tubule
Explanation:Renal protein reabsorption is the part of renal physiology that deals with the retrieval of filtered proteins, preventing them from disappearing from the body through the urine. Almost all reabsorption takes place in the proximal tubule. Only ,1% is left in the final urine.
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This question is part of the following fields:
- Medicine
- Renal
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Question 20
Correct
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Which of the following is the correct way to calculate the anion gap?
Your Answer: (Na + K) – (HCO3 + Cl)
Explanation:The anion gap is the difference between the measured cations (positively charged ions) and the measured anions (negatively charged ions) in serum, plasma, or urine. The magnitude of this difference in the serum is often calculated in medicine when attempting to identify the cause of metabolic acidosis. Anion Gap = ([Na+] + [K+]) − ([Cl−] + [HCO−3])
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This question is part of the following fields:
- Medicine
- Renal
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