Excretory System Quiz - ICSE Class 10 Biology
Free practice quiz: Excretory System (ICSE Class 10 Biology). 48 multiple-choice questions with answers and explanations. Play online, no sign-up needed.
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Which of the following is NOT a primary function of the human excretory system?
- Removal of metabolic waste products
- Regulation of blood pH and osmolarity
- Synthesis of vitamin D
- Excretion of excess salts and water
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Answer: C. Synthesis of vitamin D
While the skin, which is part of the integumentary system, plays a role in vitamin D synthesis upon exposure to UV radiation, it is not a primary function of the excretory system. The excretory system's main roles are waste removal, osmoregulation, and ion balance.
The secretion of excess hydrogen ions and potassium ions into the filtrate occurs mainly in the:
- Glomerulus
- Bowman's capsule
- Proximal convoluted tubule and distal convoluted tubule
- Loop of Henle
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Answer: C. Proximal convoluted tubule and distal convoluted tubule
Tubular secretion is an important process for eliminating certain substances from the blood into the filtrate. Both the proximal and distal convoluted tubules are involved in secreting ions like H+ and K+, as well as some drugs and waste products.
Which of the following is a key function of the loop of Henle in urine concentration?
- Active secretion of urea
- Passive diffusion of water from the descending limb
- Countercurrent exchange mechanism
- Reabsorption of amino acids
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Answer: C. Countercurrent exchange mechanism
The Loop of Henle, with its descending and ascending limbs, establishes a concentration gradient in the renal medulla through the countercurrent multiplier mechanism, which is vital for concentrating urine.
The countercurrent exchanger mechanism of the vasa recta helps to:
- Increase the osmolarity of the medulla
- Prevent the loss of the medullary osmotic gradient
- Reabsorb all filtered water
- Secrete excess glucose
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Answer: B. Prevent the loss of the medullary osmotic gradient
The vasa recta, by exchanging solutes and water with the surrounding interstitial fluid in a countercurrent manner, prevent the dilution of the highly concentrated medullary interstitial fluid established by the loop of Henle, thus preserving the osmotic gradient necessary for concentrated urine formation.
Which of the following is NOT a function of the distal convoluted tubule?
- Secretion of potassium
- Selective reabsorption of sodium
- Reabsorption of glucose
- Fine-tuning of acid-base balance
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Answer: C. Reabsorption of glucose
Glucose reabsorption primarily occurs in the proximal convoluted tubule. The distal convoluted tubule is involved in the selective reabsorption of ions (like sodium), secretion of ions (like potassium and hydrogen), and fine-tuning of water balance and acid-base balance.