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100 questions in this collection · Page 7 of 10
Question 61 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Study the structural components of the human glomerular filtration barrier:
I. The inner lining of the glomerular capillaries consists of fenestrated endothelial cells. II. The basement membrane is a cellular layer containing specialized podocyte cells. III. Podocytes line the outer visceral wall of Bowman's capsule and possess pedicels (foot processes). IV. Filtration slits (slit pores) are gaps between adjacent podocyte pedicels that act as fine physical sieves.
Statement I is correct because glomerular capillaries possess fenestrated endothelium. Statement II is incorrect because the basement membrane is an acellular extracellular matrix. Statement III is correct because podocytes line the visceral layer of Bowman's capsule and possess foot processes. Statement IV is correct because filtration slits between pedicels form part of the filtration barrier.
Question 62 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Analyze how different substances are handled by the Proximal Convoluted Tubule (PCT):
I. Water is reabsorbed actively through ATP-driven aquaporin water pumps. II. Glucose and amino acids are reabsorbed nearly 100% via active co-transport systems. III. Hydrogen ions (H+) and ammonia (NH3) are actively or passively secreted into the lumen. IV. Bicarbonate ions (HCO3-) are reabsorbed from the filtrate to sustain blood buffering capacity.
Statement I is incorrect because water is reabsorbed passively by osmosis. Statements II, III and IV are correct because glucose and amino acids are actively reabsorbed, H+ and NH3 are secreted into the filtrate, and bicarbonate ions are reabsorbed to maintain acid-base balance.
Question 63 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Consider these statements regarding the counter current multiplier and exchanger systems:
I. The loop of Henle acts as the counter current multiplier, establishing the medullary osmotic gradient. II. The vasa recta acts as the counter current exchanger, preserving the medullary gradient. III. Blood flow through the vasa recta is extremely rapid to maximize nutrient distribution throughout the medulla. IV. The counter current system minimizes the energy required to excrete concentrated urine.
Statements I and II are correct because the loop of Henle establishes the medullary gradient while the vasa recta preserves it. Statement III is incorrect because blood flow in the vasa recta is very slow, preventing washout of the osmotic gradient. Statement IV is correct because the counter current system enables efficient urine concentration.
Question 64 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Read these statements about the physiology of Antidiuretic Hormone (ADH):
I. ADH increases the water permeability of the distal convoluted tubule and collecting duct. II. Under low ADH levels, the distal parts of the nephron remain impermeable to water, leading to diuresis. III. ADH release is triggered directly by a rise in blood volume. IV. Diabetes insipidus is a condition characterized by high ADH levels and highly concentrated urine.
Statements I and II are correct because ADH increases water permeability in the DCT and collecting duct, while low ADH causes excretion of large volumes of dilute urine. Statement III is incorrect because ADH is released when blood volume decreases or plasma osmolarity increases. Statement IV is incorrect because diabetes insipidus results from ADH deficiency or lack of response to ADH, causing dilute urine.
Question 65 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Analyze the biochemical steps of the Renin-Angiotensin system:
I. Angiotensinogen is a plasma protein synthesized and released into the blood by the liver. II. Renin is a proteolytic enzyme that cleaves angiotensinogen to produce angiotensin I. III. Angiotensin-Converting Enzyme (ACE) converts angiotensin I to angiotensin II. IV. Angiotensin II is a direct inhibitor of aldosterone release from the adrenal cortex.
Statement I is correct because angiotensinogen is synthesized and released into the blood by the liver. Statement II is correct because renin cleaves angiotensinogen to form angiotensin I. Statement III is correct because ACE converts angiotensin I into angiotensin II. Statement IV is incorrect because angiotensin II stimulates, rather than inhibits, aldosterone secretion from the adrenal cortex.
Question 66 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Regarding the cardiac hormone Atrial Natriuretic Factor (ANF), choose the correct statements:
I. ANF is secreted by the ventricles of the heart in response to low systemic blood pressure. II. ANF acts as a potent vasodilator, reducing peripheral resistance and lowering blood pressure. III. ANF inhibits the release of renin from the juxtaglomerular cells. IV. The ANF mechanism operates as an antagonist check on the Renin-Angiotensin-Aldosterone System (RAAS).
Statement I is incorrect because ANF is secreted by the atria in response to increased blood volume and atrial stretching. Statements II, III and IV are correct because ANF causes vasodilation, suppresses renin release, and acts as a physiological antagonist to the RAAS.
Question 67 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Study the transport mechanisms occurring in the loop of Henle's ascending limb:
I. The thin segment of the ascending limb is highly permeable to water but impermeable to NaCl. II. The thick segment of the ascending limb actively transports sodium, potassium, and chloride ions out of the tubular fluid. III. Due to solute loss, the filtrate leaving the ascending limb is hypertonic compared to the plasma. IV. Reabsorption of solutes in this limb contributes heavily to the hyperosmolarity of the medullary interstitium.
Statement I is incorrect because the ascending limb is impermeable to water. Statement II is correct because the thick ascending limb actively transports Na+, K+, and Cl− into the medullary interstitium. Statement III is incorrect because the filtrate becomes hypotonic as solutes are removed without water loss. Statement IV is correct because this transport establishes the medullary osmotic gradient.
Question 68 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Evaluate these statements comparing cortical and juxtamedullary nephrons:
I. Cortical nephrons have their glomeruli located in the outer cortex, whereas juxtamedullary nephrons have theirs deep near the medullary border. II. Cortical nephrons are mainly adapted for water conservation under extreme dehydration. III. Juxtamedullary nephrons have a long loop of Henle extending deep into the inner medulla. IV. Cortical nephrons represent roughly 85% of all nephrons in the human kidney.
Statement I is correct because cortical and juxtamedullary nephrons differ in glomerular position. Statement II is incorrect because juxtamedullary nephrons are specialized for water conservation. Statements III and IV are correct because juxtamedullary nephrons possess long loops of Henle and cortical nephrons constitute about 85% of all nephrons.
Question 69 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Analyze the statements below regarding the renal columns of Bertini:
I. They are composed of medullary tissue extending outward into the cortex. II. They represent extensions of the renal cortex projecting between the medullary pyramids. III. They contain blood vessels supplying the cortical and medullary zones. IV. They are completely absent in healthy adult human kidneys.
Statement I is incorrect because the renal columns are cortical extensions into the medulla. Statements II and III are correct because they project between the medullary pyramids and contain interlobar blood vessels. Statement IV is incorrect because renal columns are normal structures in healthy kidneys.
Question 70 of 100
📘 CLASS XI
Excretory Products And Their Elimination
Consider these statements regarding the clinical diagnostics of glycosuria and ketonuria:
I. Glycosuria is the presence of proteins in urine, while ketonuria is the presence of ketone bodies in urine. II. Both glycosuria and ketonuria are classic diagnostic indicators of Diabetes Mellitus. III. Glycosuria is caused when blood glucose levels exceed the renal reabsorptive threshold of the PCT. IV. Ketonuria is typically observed during prolonged starvation or severe diabetes due to excessive fat catabolism.
Statement I is incorrect because glycosuria refers to the presence of glucose, not proteins, in urine. Statements II, III and IV are correct because glycosuria and ketonuria are important indicators of diabetes mellitus, glycosuria occurs when the renal threshold for glucose reabsorption is exceeded, and ketonuria develops during excessive fat breakdown in diabetes or starvation.