1) Urine is a fluid produced and excreted by the kidney passed through the ureters, stored in the bladder, and discharged through the urethra.
Which of the following is not the characteristics of urine?
a) pH 5.0 to 6.0
b) Specific gravity- approximately 1.024
c) Amber color
d) Turbid
2) Transport of sodium in the renal tubules involves:
a) Na+/K+-ATPase located on the luminal membrane of proximal tubules
b) Na+/K+-ATPase located on the membrane of distal tubules
c) The entry of sodium into tubular cells by passive transport
d) Na+ is neither reabsorbed nor secreted in the renal tubules
3) Glucose is almost completely reabsorbed in the proximal tubules and no detectable amount of sugar is present in urine from healthy individuals.
The renal threshold for glucose is approximately............................
a) 100 mg/dl
b) 140 mg/dl
c) 180 mg/dl
d) 220 mg/dl
4) What is the site of reclamation of bicarbonate?
a) Glomerulus
b) Proximal Tubules
c) Loop of Henle
d) Distal Tubules
5) In Renal tubular acidosis type I (Distal Renal Tubular Acidosis), which of the following statement is true?
a) Bicarbonate reabsorption is impaired
b) Hydrogen ion secretion is impaired
c) Urinary pH is acidic below 5.5
d) Aldosterone action is impaired.
6) Amino acids are transported via specific transporter that is present in which of the following regions?
a) Proximal tubules
b) Loop of Henle
c) Distal tubules
d) Collecting ducts
7) Approximately 90% of filtered calcium is reabsorbed in the nephron.
Which of the following hormone increases absorption of calcium in an autocrine manner?
a) Parathyroid hormone
b) Antidiuretic hormone
c) Vit D3
d) Erythropoietin
8) The reabsorption of phosphate occurs via a secondary transport system.
Which of the following ion is co-transported with the phosphate ion?
a) Calcium
b) Sodium
c) Potassium
d) Magnesium
9) The urea is passively reabsorbed from the renal tubules along with sodium and water reabsorption. The passive reabsorption is also facilitated by specific urea transports on..........................................?
a) Proximal tubules
b) Loop of Henle
c) Distal Tubule
d) Collecting duct
10) Which of the following tubular absorption process require ATP?
a) The movement of molecules or ions moving down their concentration gradient
b) The movement of impermeable molecules across the membrane down their concentration gradient associated with proteins
c) A protein-mediated transport against the concentration gradient
d) None of the above
11) Which of the following transporters is not the symporter that facilitates the transport of both molecules inside the membrane?
a) Na+/K+ transporter
b) Na+/Glucose transporter
c) Na+/Phosphate transporter
d) Na+/Amino acid transporter
12) The following transporter is an example of a uniport system, EXCEPT
a) Na+/K+ ATPase
b) Na+/H+ ATPase
c) Na+/Ca++ ATPase
d) Na+/Phosphate ATPase
13) What is the reabsorption rate of glucose in a patient with uncontrolled diabetes mellitus with:
Glomerular filtration rate = 120 ml/min,
Plasma glucose concentration = 350 mg/ml,
Urine glucose concentration 2000 mg/ml,
Total urine volume 4.32 L or 3mL/min
a) 320 mg/min
b) 360 mg/min
c) 400 mg/ml
d) 440 mg/ml
14) The proximal tubules undergo isosmotic reabsorption with the osmolality close to 300 mOsm/kg (similar to plasma).
Which of the following process helps maintain the osmolality?
a) Two-thirds of the filtered water and potassium are reabsorbed through the kidney
b) Two-thirds of the filtered sodium is reabsorbed in the proximal tubules
c) Na+ coupled cotransport of glucose, amino acid, and organic acids occurs in proximal tubules
d) All of the above
15) About 80% of filtered bicarbonate is reabsorbed in proximal tubules.
Which of the following enzymes or transporter is involved in the reabsorption of bicarbonate?
a) Na+/K+ ATPase basolateral surface
b) Na+/H+ ATPase in the luminal surface
c) Carbonic anhydrase in tubules and proximal tubules
d) All of the above
16) Which of the following parts of the nephrons is important for the concentration of urine and has the highest osmolality?
a) Proximal tubules
b) Loop of Henle
c) Distal tubules
d) Collecting ducts
17) Renal tubular acidosis type I is the result of the low arterial blood pH, accumulation of fixed acids, and hypokalemia.
Which of the following statement is true about this type of acidosis?
a) Bicarbonate reabsorption in proximal tubules is impaired
b) Hydrogen ion secretion in the distal tubules is impaired
d) Aldosterone secretion/action is impaired
d) None of the above
18) Renal tubular acidosis IV is the result of the inability to secrete potassium leading to hyperkalemia, decreased hydrogen secretion, and metabolic acidosis.
Which of the following is true about renal tubular acidosis IV?
a) Bicarbonate reabsorption in proximal tubules is impaired
b) Hydrogen ion secretion in the distal tubules is impaired
d) Aldosterone secretion/action is impaired.
c) Urinary pH is acidic below 5.5
19) The thiazide diuretics inhibit the reabsorption of sodium and chloride by inhibiting Na+ Cl- a co-transporter system that is present in........................................?
a) Proximal tubules
b) Loop of Henle
c) Early Distal tubules
d) Late Distal tubules
20) Which of the following is not the function of late distal tubules and collecting ducts?
a) Reabsorption of sodium and water
b) Site of action of aldosterone
c) Reabsorption of hydrogen ions
d) Site of ADH action
Multiple Choice Answers:
1-d) Turbid
2-a) Na+/K+-ATPase located on the luminal membrane of proximal tubules.
The Na+/K+-ATPase is primarily located on the basolateral membrane (the side facing the bloodstream) of the epithelial cells in the proximal tubules. In the proximal tubules, sodium enters the epithelial cells from the tubular lumen primarily through various sodium transporters and channels on the luminal membrane.
The Na+/K+-ATPase pump on the basolateral membrane maintains a low intracellular sodium concentration by pumping sodium out into the interstitial fluid. This creates a favorable gradient for sodium to enter the cells from the tubular lumen.
3-c) 180 mg/dl.
The renal threshold for glucose is the blood glucose concentration at which the kidneys start to excrete glucose into the urine. In most healthy individuals, the renal threshold for glucose is approximately 180-200 mg/dL (10-11 mmol/L).
4-b) Proximal Tubules.
The reclamation of bicarbonate is a crucial process carried out by the kidneys to maintain acid-base balance in the body. This process primarily occurs in the proximal tubules, but also involves the distal tubules and collecting ducts.
5-b) Hydrogen ion secretion is impaired.
In RTA Type I, the cells in the distal tubules and collecting ducts are unable to secrete hydrogen ions (H+) effectively into the tubular lumen. This is often due to defects in the H+-ATPase pump or the H+/K+-ATPase antiporter on the apical membrane of the tubular cells.
6-a) Proximal tubules
7-c) Vit D3
8-b) Sodium
9-d) Collecting duct
10-c) A protein-mediated transport against the concentration gradient
11-a) Na+/K+ transporter
12-d) Na+/phosphate ATPase
13-b) 360 mg/min
14-d) All of the above
15-d) All of the above
16-b) Loop of Henle
17-d) Aldosterone secretion/action is impaired
18-b) Hydrogen ion secretion in the distal tubules is impaired
19-c) Early Distal tubules
20-c) Reabsorption of hydrogen ions