Excretory System — Set 3
Biology · उत्सर्जन तंत्र · Questions 21–30 of 50
Which artery supplies oxygenated blood to the kidneys?
Correct Answer: B. Renal artery
The renal artery branches directly from the abdominal aorta to bring blood to the kidney for filtration. About 20% of the total cardiac output passes through the kidneys every minute. This high blood flow is necessary for effective waste removal.
The presence of kidney stones is medically known as?
Correct Answer: C. Nephrolithiasis
Nephrolithiasis refers to the formation of hard mineral deposits within the kidneys. These stones are most commonly made of calcium oxalate. They can cause severe pain when they block the flow of urine.
What is the approximate volume of blood filtered by the kidneys in a healthy adult every day?
Correct Answer: C. 180 Liters
The kidneys filter about 180 liters of blood daily to produce glomerular filtrate. However, 99% of this filtrate is reabsorbed back into the bloodstream. Only about 1.5 liters of urine are actually excreted per day.
Which part of the brain controls the voluntary aspect of micturition?
Correct Answer: B. Cerebral Cortex
The cerebral cortex allows us to consciously decide when to relax the external urethral sphincter. Infants lack this voluntary control as their nervous system is still developing. This higher-level control is what enables toilet training.
What happens to the level of ADH in the blood during excessive sweating?
Correct Answer: D. It increases
The correct answer is 'It increases'. Sweating causes water loss, which triggers the hypothalamus to signal the release of more ADH. Higher ADH levels promote water reabsorption in the kidneys to prevent further dehydration. This results in the production of more concentrated urine.
The condition characterized by the inflammation of the glomeruli is called?
Correct Answer: A. Glomerulonephritis
Glomerulonephritis is an inflammation of the tiny filters in the kidney. It can lead to blood and protein appearing in the urine. Chronic inflammation can eventually cause permanent kidney damage.
Which mineral is most commonly found in the composition of human kidney stones?
Correct Answer: D. Calcium oxalate
Calcium oxalate is the primary component in about 80% of kidney stone cases. Dehydration and certain dietary habits can increase the risk of stone formation. Drinking plenty of water is the most effective way to prevent them.
Which structure in the nephron is responsible for the majority of nutrient reabsorption?
Correct Answer: A. Proximal Convoluted Tubule
The Proximal Convoluted Tubule (PCT) reabsorbs nearly all glucose, amino acids, and 70% of salts. Its surface is lined with microvilli to increase the area available for absorption. This is an active process requiring significant energy.
What is the function of the vasa recta in the kidney?
Correct Answer: A. Maintaining medullary gradient
Vasa recta are long, straight capillaries that run parallel to the loop of Henle. They help maintain the osmotic gradient in the renal medulla by acting as counter-current exchangers. This gradient is vital for producing concentrated urine.
Which type of animal is specifically adapted to excrete uric acid to conserve water?
Correct Answer: C. Birds
Birds and reptiles are uricotelic, meaning they convert nitrogenous waste into a paste-like uric acid. Uric acid is the least toxic and requires the minimum amount of water for excretion. This adaptation is crucial for survival in dry environments or inside eggs.