Human Excretory System – 1:
1. Which of the following is not included in the excretory system of humans?
A. Cloaca
B. Kidneys
C. Ureters
D. Urethra
Answer: A
Explanation: In humans, the excretory system consists of a pair of kidneys, one pair of ureters, a urinary bladder, and urethra. Kidneys are reddish-brown and bean-shaped structures.
2. Where are the kidneys situated?
A. Between the 7th and 10th ribs
B. Between the last thoracic and third lumbar vertebra
C. Between the 8th and 9th ribs
D. Between the first and second thoracic vertebra
Answer: B
Explanation: Kidneys are reddish-brown, bean-shaped structures situated between the levels of the last thoracic and third lumbar vertebra close to the dorsal inner wall of the abdominal cavity.
3. What is the average weight of a human kidney?
A. 40 g
B. 100 g
C. 120 g
D. 10 g
Answer: C
Explanation: Each kidney of an adult human measures for about 10-12 cm in length, 5-7 cm in width, and 2-3 cm in thickness with an average weight of 120-170 grams.
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4. Through which of the following nerves and blood vessels enter the kidneys?
A. Hilum
B. Tubules
C. Pelvis
D. Medulla
Answer: A
Explanation: Through the hilum, the nerves, the ureters and the blood vessels enter the kidneys. The hilum is a notch which is present towards the centre of the inner concave surface of the kidney.
5. Inside the kidney, there are three zones.
A. True
B. False
Answer: B
Explanation: The outer layer of the kidney is a tough capsule. Inside the kidney, there are two zones, an outer cortex, and an inner medulla. Inner to the hilum, a broad funnel-shaped space is presently called the renal pelvis.
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6. Which of the following is responsible for the formation of Columns of Bertini?
A. Medulla
B. Renal pelvis
C. Calyces
D. Cortex
Answer: D
8. How many nephrons are present in each kidney?
A. One million
B. One billion
C. One trillion
D. Two million
Answer: A
Explanation: Each kidney has approximately one million complex tubular structures called nephrons. These nephrons are the structural and functional units of the kidneys.
9. In how many parts a nephron is divided?
A. One
B. Two
C. Three
D. Four
Answer: B
Explanation: Each nephron is divided into two parts- the glomerulus and the renal tubule. The glomerulus is a tuft of capillaries while the renal tubule begins with a double-walled cup-like structure called Bowman’s capsule.
10. What will happen if the diameter of the afferent arteriole is less than efferent arteriole?
A. Dilute urine
B. Concentrated urine
C. No ultrafiltration
D. Black urine
Answer: C
12. Starfishes are aminotelic organisms.
A. True
B. False
Answer: A
Explanation: Starfishes are aminotelic organisms as they excrete amino acids directly into the urine. Hippuric acid is an excretory waste formed by the combination of benzoic acid and glycine in mammals.
13. What are osmoregulators?
A. Animals which cannot change their body osmolarity
B. Animals which can change their osmolarity sometimes
C. Animals which can change their osmolarity
D. Animals which cannot excrete out waste
Answer: A
Explanation: Osmoregulators are the animals that cannot change their body osmolarity according to their external environment. They cannot tolerate a wide range of salinity.
14. Which of the following organism is not an osmoconformer?
A. Hagfish
B. Spongilla
C. Marine invertebrates
D. Skates
Answer: B
Explanation: Osmoconformers are the animals that can change their body osmolarity according to the external environment like hagfish, marine invertebrates, sharks, and skates.
‘A. Drinks water
B. Feeds on fatty seeds
C. Excretes concentrated urine
D. The nasal counter current system
Answer: A
