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100 questions in this collection · Page 9 of 10
Question 81 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Study the structural features of the human kidney's outer and inner zones:
I. The cortex forms the outer zone, and the medulla forms the inner zone. II. The renal medulla is divided into several conical masses called medullary pyramids. III. Medullary pyramids project directly into the broad, funnel-shaped renal pelvis. IV. The Columns of Bertini represent the extensions of the cortex between the medullary pyramids.
Statements I, II and IV are correct. Statement III is incorrect because the medullary pyramids project into the calyces, not directly into the renal pelvis.
Question 82 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Evaluate these statements about glomerular filtration and renal blood flow:
I. On average, the kidneys filter about 1100–1200 ml of blood per minute. II. The amount of blood filtered by the kidneys per minute constitutes roughly 1/5th of the cardiac output of each ventricle. III. The filtration of blood through the glomerulus is driven by high glomerular capillary blood pressure. IV. Since blood is filtered so finely, all cellular and plasma elements, including proteins, enter Bowman's capsule.
Statements I, II and III are correct. Statement IV is incorrect because proteins and blood cells are normally retained in the blood, while the filtrate entering Bowman's capsule is essentially protein-free.
Question 83 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Read the statements below regarding the Juxtaglomerular Apparatus (JGA):
I. JGA is a specialized region formed by cellular modifications in the distal convoluted tubule and afferent arteriole. II. A rise in GFR stimulates the immediate release of renin from the JG cells. III. Renin stimulates glomerular blood flow to bring a depressed GFR back to normal. IV. The JGA acts as an efficient intrinsic autoregulatory mechanism of the kidney.
Statement I is correct because the JGA is formed by cellular modifications at the contact point of the distal convoluted tubule and afferent arteriole. Statement II is incorrect because a fall, not a rise, in GFR stimulates the JG cells to release renin. Statement III is correct because renin helps restore glomerular blood flow and GFR. Statement IV is correct because the JGA functions as an intrinsic autoregulatory mechanism of the kidney.
Question 84 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Consider these statements regarding the transport activities in the Proximal Convoluted Tubule (PCT):
I. The PCT is lined by simple cuboidal brush border epithelium, which maximizes surface area for reabsorption. II. About 70–80 per cent of electrolytes and water are reabsorbed in this segment. III. Virtually all essential nutrients are reabsorbed by the PCT. IV. The PCT maintains pH by selectively secreting bicarbonate ions (HCO3-) and absorbing hydrogen ions (H+).
Statements I, II and III are correct. Statement IV is incorrect because the PCT maintains pH by secreting H+ and ammonia into the filtrate while reabsorbing HCO3- from the filtrate.
Question 85 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Study the hormonal action of Antidiuretic Hormone (ADH) on water balance:
I. Dehydration or fluid loss activates osmoreceptors, stimulating the neurohypophysis to release ADH. II. ADH facilitates water reabsorption from the proximal convoluted tubule. III. ADH prevents diuresis by promoting water conservation in the latter parts of the tubule. IV. An increase in body fluid volume completes the feedback loop by switching off the osmoreceptors.
Statement I is correct because dehydration activates osmoreceptors and stimulates ADH release from the posterior pituitary. Statement II is incorrect because ADH acts mainly on the distal convoluted tubule and collecting duct, not the PCT. Statements III and IV are correct because ADH promotes water reabsorption and increased body fluid volume suppresses further ADH release.
Question 86 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Examine these statements about the vascular and hemodynamic actions of ADH:
I. ADH can affect kidney function via its constrictory effects on blood vessels. II. Vasoconstriction caused by ADH leads to a localized decrease in glomerular blood pressure. III. An increase in blood pressure caused by ADH increases glomerular blood flow and thereby the GFR. IV. ADH acts as a physiological vasodilator to lower heart workload.
Statement I is correct because ADH has vasoconstrictor action on blood vessels. Statement II is incorrect because vasoconstriction increases blood pressure. Statement III is correct because increased blood pressure enhances glomerular blood flow and GFR. Statement IV is incorrect because ADH is a vasoconstrictor (vasopressin), not a vasodilator.
Question 87 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Analyze the statements below regarding the Renin-Angiotensin system:
I. A fall in glomerular blood pressure or GFR triggers JGA cells to release renin. II. Renin converts angiotensinogen in the blood into angiotensin I. III. Angiotensin II is a powerful vasodilator that lowers systemic blood pressure. IV. Angiotensin II stimulates the adrenal cortex to secrete aldosterone.
Statements I and II are correct because reduced glomerular blood pressure or GFR stimulates renin release, and renin converts angiotensinogen into angiotensin I. Statement III is incorrect because angiotensin II is a powerful vasoconstrictor, not a vasodilator. Statement IV is correct because angiotensin II stimulates aldosterone secretion from the adrenal cortex.
Question 88 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Evaluate the statements below regarding the actions of Aldosterone and ANF:
I. Aldosterone promotes Na+ and water reabsorption in the distal parts of the tubule. II. Aldosterone secretion causes an increase in blood pressure and GFR. III. Atrial Natriuretic Factor (ANF) is secreted by the atria of the heart in response to increased blood flow. IV. ANF causes vasoconstriction and raises systemic blood pressure to check the JGA mechanism.
Statements I, II and III are correct. Statement IV is incorrect because ANF causes vasodilation and decreases blood pressure, acting as a physiological antagonist to the renin-angiotensin mechanism.
Question 89 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Consider these statements regarding the physiology of the micturition reflex:
I. The micturition reflex is initiated by stretch receptors on the walls of the urinary bladder as it fills with urine. II. The CNS coordinates motor signals to cause contraction of bladder smooth muscle and simultaneous relaxation of the urethral sphincter. III. An adult human excretes, on average, 5 to 7 litres of urine per day. IV. Normal human urine is slightly acidic, with an average pH of 6.0.
Statements I, II and IV are correct. Statement III is incorrect because a healthy adult excretes about 1 to 1.5 litres of urine per day, not 5 to 7 litres.
Question 90 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Evaluate these statements about urine diagnostics and metabolic disorders:
I. On average, a healthy human excretes 25–30 gm of urea per day. II. Analysis of urine is highly valuable for the clinical diagnosis of metabolic disorders and kidney malfunction. III. The presence of glucose (Glycosuria) in urine is a normal finding in healthy individuals. IV. Ketonuria (presence of ketone bodies in urine) is a classic diagnostic indicator of diabetes mellitus.
Statements I, II and IV are correct. Statement III is incorrect because glycosuria is an abnormal finding and is commonly associated with diabetes mellitus.