Function of Tubules-2:
1. In which of the following segments, conditional reabsorption of sodium ions take place?
A. PCT
B. DCT
C. Collecting duct
D. Henle’s loop
Answer: B
Explanation: Conditional reabsorption of sodium ions and water takes place in the distal convoluted tubule. This segment is also capable of the reabsorption of HCO3– ions.
2. Which of the following segments are responsible for maintaining the sodium-potassium balance?
A. Ascending loop of Henle
B. Descending loop of Henle
C. DCT
D. Glomerulus
Answer: C
Explanation: Selective secretion of hydrogen and potassium ions and ammonia maintain the pH and also the sodium-potassium balance in the body by reabsorption of bicarbonate ions.
3. The collecting duct extends from the cortex of the kidney to which of the following parts?
A. Outer parts of medulla
B. Inner parts of medulla
C. Into the medullary pyramids
D. Into the renal pelvis
Answer: B
Explanation: The collecting duct is a long duct which extends from the cortex of the kidney to the inner parts of the medulla. Large amounts of water can also be reabsorbed through this segment.
4. Which of the following segments can allow the passage of urea through them?
A. Collecting duct
B. PCT
C. DCT
D. Henle’s loop
Answer: A
Explanation: Through the collecting duct, large amounts of water can be reabsorbed to produce concentrated urine. This segment also allows the passage of small amounts of urea into the medullary interstitium to keep up the osmolarity.
5. The collecting duct plays no role in secretion.
A. True
B. False
Answer: B
Explanation: Collecting duct plays a significant role, along with PCT and DCT in the secretion of hydrogen and potassium ions to maintain the pH and ionic balance of the blood.
6. What are diuretics?
A. Substances which increase the urine formation
B. Substances which decrease the urine formation
C. Substances which increase the glucose content in the urine
D. Substances which change the colour of the urine
Answer: A
Explanation: Diuretics are substances that produce more urine output. These include tea, alcohol, coffee, etc. These substances suppress the release of anti-diuretic hormone.
7. Which of the following is called a salt retaining hormone?
A. ANF
B. ADH
C. Oxytocin
D. Aldosterone
Answer: D
Explanation: Aldosterone is secreted by the adrenal cortex and is also known as the salt retaining hormone because its main function is the reabsorption of NaCl in blood and excretion of potassium ions in the blood.
8. Hyposecretion of ADH causes which of the following diseases?
A. Diabetes mellitus
B. Diabetes insipidus
C. Addison’s disease
D. Simmonds’s disease
Answer: B
Explanation: Hyposecretion of Anti-diuretic hormone causes diabetes insipidus, i.e., urine without glucose. Hyposecretion of aldosterone causes Addison’s disease which is characterized by the darkening of the skin.
9. What happens due to the increase of sodium ions in the blood?
A. Increase in blood pressure
B. A decrease in blood pressure
C. Increase in the solubility of nitrogen
D. A decrease in solubility of sodium ions
Answer: A
Explanation: More sodium ions in the blood or fewer potassium ions in the blood lead to increased blood pressure and blood volume. This condition can be a symptom of the hypersecretion of the salt retaining hormone, i.e., aldosterone.
10. What happens when there is an increase in sodium ions in the urine?
A. Increase in blood pressure
B. Increase in blood volume
C. A decrease in blood pressure
D. A decrease in the solubility of sodium ions
Answer: C
Explanation: More sodium ions in the urine or fewer potassium ions in the urine can lead to a decrease in blood pressure and blood volume. This can be due to the hyposecretion of Aldosterone.
11. Macula densa of DCT are sensitive to magnesium ions.
A. True
B. False
Answer: B
Explanation: Macula densa of DCT is sensitive to NaCl. These are the cells of DCT epithelium which are in contact with the arteriolar wall and are denser than other epithelial cells.
12. Juxtaglomerular cells are the modifications of which of the following?
A. Smooth muscle cells
B. Skeletal muscle cells
C. Adipocytes
D. Areolar cells
Answer: A
Explanation: Juxtaglomerular cells are modified smooth muscle cells of the afferent renal arteriole which secrete renin. This renin is a hormone cum enzyme. It goes from the kidney to the liver. When the liver detects renin, then it releases angiotensinogen which changes into angiotensin I.
13. What is the myogenic mechanism of the kidney?
A. As blood pressure increases, arteries get constricted
B. As blood pressure decreases, arteries get dilated
C. As blood pressure increases, efferent renal arteriole dilates
D. As blood pressure increases, afferent renal arteriole dilates
Answer: C
Explanation: Myogenic mechanism of the kidney is the main mechanism to regulate the glomerular filtration rate. As the blood pressure increases, the efferent renal arteriole gets dilated and hence reduces the blood pressure.
14. Which of the following organs does not help in the elimination of excretory wastes?
A. Skin
B. Lungs
C. Liver
D. Heart
Answer: D
Explanation: Other than kidneys, lungs, liver, and skin also helps in the elimination of excretory wastes. Our lungs remove large amounts of CO2 and also significant quantities of water every day.
15. Which of the following is not an excretory waste of liver?
A. Cholesterol
B. Bilirubin
C. CO2
D. Vitamins
Answer: C
