Excretory System — Set 4
Biology · उत्सर्जन तंत्र · Questions 31–40 of 50
The hormone 'Erythropoietin', which stimulates red blood cell production, is primarily secreted by the?
Correct Answer: D. Kidney
Kidneys release erythropoietin in response to low oxygen levels in the blood. This hormone travels to the bone marrow to trigger the formation of new red blood cells. Chronic kidney disease often results in anemia due to low production of this hormone.
Which of the following is a primary waste product removed by the lungs?
Correct Answer: B. Carbon dioxide
The lungs excrete carbon dioxide and water vapor as byproducts of cellular respiration. Carbon dioxide is transported in the blood to the alveoli for gas exchange. Efficient removal of CO2 is essential for maintaining blood pH levels.
Which vessel carries filtered blood away from the kidney back to the heart?
Correct Answer: C. Renal vein
The renal vein collects blood from the kidney and drains into the inferior vena cava. This blood has a lower concentration of metabolic wastes compared to the blood in the renal artery. It also carries the reabsorbed nutrients back to the systemic circulation.
What is the name of the sphincter muscle that allows voluntary control over urination?
Correct Answer: D. External urethral sphincter
The external urethral sphincter is made of skeletal muscle and is under conscious control. The internal sphincter, however, is made of smooth muscle and functions involuntarily. Coordinated action of both is required for normal micturition.
Urine is temporarily stored in which of the following structures?
Correct Answer: C. Urinary bladder
The urinary bladder is a stretchable muscular sac that holds urine until it is convenient to void. It can typically hold between 400 to 600 ml of urine in a healthy adult. The urge to urinate usually begins when it is about half full.
What is the primary function of the renin-angiotensin-aldosterone system (RAAS)?
Correct Answer: D. Regulating blood pressure
The RAAS is a hormonal complex that helps regulate blood pressure and fluid balance. When blood pressure drops, the kidneys release renin to initiate this system. It ultimately leads to salt and water retention to raise pressure.
Which structure connects the urinary bladder to the outside of the body?
Correct Answer: B. Urethra
The urethra is the canal through which urine is discharged from the body. In males, it is longer and also serves as a passage for reproductive fluids. In females, it is shorter and strictly part of the urinary system.
What is the effect of caffeine and alcohol on urine production?
Correct Answer: D. Increase production
The correct answer is 'Increase production'. Caffeine and alcohol act as diuretics by inhibiting the action of ADH. This prevents the kidneys from reabsorbing water, leading to more frequent urination. This can contribute to dehydration if water intake is not maintained.
The outer region of the kidney, between the renal capsule and the renal medulla, is the?
Correct Answer: B. Renal cortex
The renal cortex is the granular-looking outer layer containing the renal corpuscles. It provides space for the arterioles and venules of the kidney. Most of the filtration process begins in this outer region.
Which of the following conditions is characterized by high levels of urea in the blood?
Correct Answer: D. Uremia
Uremia is a dangerous condition that occurs when the kidneys are unable to filter urea effectively. It is a sign of end-stage renal disease or acute kidney injury. It can lead to fatigue, nausea, and even coma if untreated.