-
Question 1
Correct
-
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.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 2
Correct
-
What is the function of the macula densa, located in the wall of the thick ascending limb?
Your 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.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 3
Correct
-
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.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 4
Incorrect
-
The position of the kidneys besides the vertebral column retroperitoneally spans levels:
Your Answer: T11 – L2
Correct Answer: T12 – L3
Explanation:The asymmetry within the abdominal cavity, caused by the position of the liver, typically results in the right kidney being slightly lower and smaller than the left, and being placed slightly more to the middle than the left kidney. The left kidney is approximately at the vertebral level T12 to L3, and the right is slightly lower.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 5
Correct
-
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.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 6
Incorrect
-
ANP and BNP in the circulation act on the kidney to?
Your Answer: Increase rennin secretion
Correct 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.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 7
Correct
-
The Na-K-2Cl co-transporter occurs in which part of the renal tubule?
Your Answer: Apical surface of thick ascending limb
Explanation:The Na-K-Cl cotransporter (NKCC) is a protein that aids in the active transport of sodium, potassium, and chloride into cells. In humans there are two isoforms of this membrane transport protein, NKCC1 and NKCC2. NKCC2 is specifically found in cells of the thick ascending limb of the loop of Henle and the macula densa in nephrons, the basic functional units of the kidney. Within these cells, NKCC2 resides in the apical membrane abutting the nephron’s lumen.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 8
Incorrect
-
Which of the following stimulate the release of aldosterone from the adrenal cortex?
Your Answer: Renin
Correct Answer: Angiotensin 2
Explanation:Angiotensin II also stimulates the secretion of the hormone aldosterone from the adrenal cortex. Aldosterone causes the renal tubules to increase the reabsorption of sodium and water into the blood, while at the same time causing the excretion of potassium (to maintain electrolyte balance).
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 9
Correct
-
Where is most of the filtered sodium reabsorbed?
Your Answer: Proximal tubule
Explanation:Renal reabsorption of sodium (Na+) is a part of renal physiology. It uses Na-H antiport, Na-glucose symport, sodium ion channels (minor). It is stimulated by angiotensin II and aldosterone, and inhibited by atrial natriuretic peptide. Most of the reabsorption (65%) occurs in the proximal tubule.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 10
Correct
-
Erythropoietin is synthesized by which cells of the nephron?
Your 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.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 11
Incorrect
-
The interstitium of the kidney is most hypertonic in the:
Your Answer: Outer cortex
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.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 12
Incorrect
-
In a 70 kg male, the approximate volumes (litres) of water in the different compartments mentioned (intracellular, interstitial, vascular) are:
Your Answer: 25l, 12l, 5l
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.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 13
Correct
-
What effect does osmotic diuresis have on net Na+ excretion?
Your Answer: Markedly increased Na+ excretion
Explanation:Osmotic diuresis is the increase of urination rate caused by the presence of certain substances in the small tubes of the kidneys. The excretion occurs when substances such as glucose enter the kidney tubules and cannot be reabsorbed (due to a pathological state or the normal nature of the substance). The substances cause an increase in the osmotic pressure within the tubule, causing retention of water within the lumen, and thus reduces the reabsorption of water, increasing urine output (i.e. diuresis). Sodium, chloride, potassium are markedly excreted in osmotic diuresis.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 14
Incorrect
-
If UA = concentration of A in urine, V = urine flow per unit time, and PA = arterial plasma level of A, renal clearance of A is equal to?
Your Answer: PA/(UA x V)
Correct Answer: (UA x V)/PA
Explanation:Renal clearance = [Urine concentration (UA) x Urine flow (V)]/[Plasma concentration (PA)]
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 15
Incorrect
-
Where are the principal cells found in the kidney?
Your Answer: Proximal convoluted tubule
Correct Answer: Collecting ducts
Explanation:A kidney collecting duct cell can be of two different cell types:Principal cellsIntercalated cells
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 16
Incorrect
-
An important enzyme in renal tissue responsible for the conversion of glutamine to glutamate and the subsequent production of NH4 is called?
Your Answer: Glutamic dehydrogenase
Correct Answer: Glutaminase
Explanation:Glutaminase catalyses the following reaction:Glutamine + H2O → Glutamate + NH3
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 17
Incorrect
-
Using the Cockcroft-Gault formula, what will the estimated creatinine clearance be of a 55 year old male who weighs 75kg and has a serum creatinine of 150mg/dL?
Your Answer: 0.44ml/min
Correct Answer: 0.59ml/min
Explanation:A commonly used surrogate marker for estimate of creatinine clearance is the Cockcroft-Gault (CG) formula, which in turn estimates GFR in ml/min:CCr = [(140-age) x Mass(kg)]/[72 x serum creatinine (mg/dL)](multiply by 0.85 for women)Therefore CCr = (85 x 75)/(72 x 150) = 0.59
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 18
Correct
-
Erythropoietin is synthesized by which cells of the nephron?
Your 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.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 19
Incorrect
-
ADH causes?
Your Answer: Upregulates aquaporin 1
Correct 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.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 20
Incorrect
-
What is the most important determinant of ECF volume?
Your Answer: The amount of potassium in the ECF
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.
-
This question is part of the following fields:
- Medicine
- Renal
-
SESSION STATS - PERFORMANCE PER SPECIALTY
