Given below are statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Nephrons are of two types: Cortical & Juxta medullary, based on their relative position in cortex and
medulla. Reason R: Juxta medullary nephrons have short loop of Henle whereas, cortical nephrons have longer loop of Henle.
In the light of the above statements, choose the correct answer from the options given below:
AI-generated explanation. Check against your textbook.
Explanation:
Assertion A is true: Nephrons are of two main types, cortical and juxta medullary, based on their position in the cortex and medulla. Reason R is false: in NCERT, juxtamedullary nephrons have a long loop of Henle that extends deep into the medulla, whereas cortical nephrons have a shorter loop. Therefore, A is true and R is not a correct explanation for A.
🧠 Did You Know?
Juxtamedullary nephrons help in producing concentrated urine due to their long loops of Henle, enabling a strong osmotic gradient in the medulla.
💡 NCERT Memory Line:
There are two types of nephrons—cortical and juxtamedullary—distinguished by their position, with juxtamedullary nephrons having longer loops of Henle.
Which of the following statements are correct?
A.An excessive loss of body fluid from the body switches off osmoreceptors.
B.ADH facilitates water reabsorption to prevent diuresis.
C.ANF causes vasodilation.
D.ADH causes increase in blood pressure.
E.ADH is responsible for decrease in GFR.
Choose the correct answer from the options given below:
AI-generated explanation. Check against your textbook.
Explanation:
Correct option: B, C and D. B) ADH (vasopressin) promotes water reabsorption in the kidney, thus reducing diuresis. C) ANF (ANP) causes vasodilation. D) ADH can cause vasoconstriction, raising blood pressure. A) Excessive loss of body fluid increases osmolarity and stimulates osmoreceptors; it does not switch them off. E) ADH mainly saves water and does not cause a direct decrease in GFR as a primary effect in NCERT context. Hence E is not correct.
🧠 Did You Know?
NCERT notes that ADH increases water reabsorption in collecting ducts and can influence arteriolar tone to help maintain blood pressure.
💡 NCERT Memory Line:
ADH prevents diuresis by reabsorbing water in the collecting ducts; ANF causes vasodilation and promotes diuresis.
The increase in osmolarity from outer to inner medullary interstitium is maintained due to:
I. Close proximity between Henle's loop and vasa recta
II. Counter current mechanism
III. Selective secretion of HCO3- and hydrogen ions in PCT
IV. Higher blood pressure in glomerular capillaries
AI-generated explanation. Check against your textbook.
Explanation:
The osmolarity of the renal medulla increases from outer to inner due to the countercurrent mechanism involving the loop of Henle and the vasa recta. This is achieved mainly because of their close proximity and interaction (I and II). Options III and IV are not the primary reasons for this gradient: III refers to secretion in the proximal convoluted tubule, which relates to acid-base balance, not medullary osmolarity; IV (high glomerular blood pressure) does not establish the medullary osmotic gradient. Therefore, the correct combination is I and II.
🧠 Did You Know?
NCERT explains that the countercurrent mechanism in the loop of Henle and the surrounding vasa recta creates and preserves the medullary osmotic gradient essential for water reabsorption.
💡 NCERT Memory Line:
Countercurrent mechanism and close interaction of loop of Henle with vasa recta maintain increasing osmolarity from outer to inner medulla.
Presence of which of the following conditions in
urine are indicative of Diabetes Mellitus?
AI-generated explanation. Check against your textbook.
Explanation:
Option 3 is correct. In Diabetes Mellitus, high blood glucose leads to glycosuria (glucose in urine) when renal threshold is exceeded. Insufficient insulin causes fat breakdown, producing ketone bodies, leading to ketonuria. Thus both glycosuria and ketonuria are indicative of diabetes.
🧠 Did You Know?
Glycosuria and ketonuria together suggest poor glycemic control in diabetes and possible diabetic ketoacidosis if severe.
💡 NCERT Memory Line:
In Diabetes Mellitus there is glycosuria and ketonuria due to hyperglycemia and fat breakdown.
Use of an artificial kidney during hemodialysis may
result in:
(A) Nitrogenous waste build-up in the body
(B) Non-elimination of excess potassium ions
(C) Reduced absorption of calcium ions from gastrointestinal tract
(D) Reduced RBC production
Which of the following options is the most
appropiate?
AI-generated explanation. Check against your textbook.
Explanation:
Use of an artificial kidney (hemodialysis) removes nitrogenous wastes and excess ions from the blood, so it does not cause waste build-up (A) or non-elimination of potassium (B). NCERT explains that kidney disease can disturb vitamin D activation, leading to reduced calcium absorption from the gut, and kidney failure lowers erythropoietin production, reducing RBC production (D). Thus, (C) and (D) are considered correct in this context.
🧠 Did You Know?
In kidney disease, less erythropoietin is made, so doctors sometimes give synthetic EPO to treat anemia associated with reduced RBC production.
💡 NCERT Memory Line:
Kidney failure affects vitamin D activation and erythropoietin production, which can alter calcium absorption and red blood cell formation.
Statements I: In the nephron the descending limb of loop of Henle is impermeable to water and permeable to electrolytes.
Statement II: The proximal convoluted tubule is lined by simple columnar brush border epithelium
and increases the surface area for reabsorption.
In the light of the above statements, choose the
correct answer fropm the options given below:
AI-generated explanation. Check against your textbook.
Explanation:
Statement I is false: the descending limb of the loop of Henle is permeable to water and relatively impermeable to electrolytes; the ascending limb is impermeable to water and actively transports ions. Statement II, in essence, is true: the proximal convoluted tubule is lined by a simple cuboidal epithelium with a brush border (microvilli) that increases the surface area for reabsorption. The exact NCERT phrase emphasizes the brush border and increased reabsorption capacity, though it uses cuboidal rather than columnar wording.
🧠 Did You Know?
Brush border microvilli drastically increase the absorptive surface area, helping reabsorb filtered substances from the tubule into the blood.
💡 NCERT Memory Line:
Proximal convoluted tubule is lined by simple cuboidal epithelium with a brush border to maximize reabsorption.