NEETZoologyChemical Coordination and Integration
Consider the following sequence of physiological responses to excessive fluid loss from the body: Excessive loss of fluid activates [P] stimulates hypothalamus releases [Q] from neurohypophysis causes [R] of blood vessels leads to [S] in glomerular blood flow and GFR. Identify [P], [Q], [R], and [S] correctly.
Options
- A[P] Chemoreceptors, [Q] ADH, [R] Dilation, [S] Decrease
- B[P] Osmoreceptors, [Q] ANF, [R] Constriction, [S] Increase
- C[P] Osmoreceptors, [Q] ADH, [R] Constriction, [S] Increase
- D[P] Osmoreceptors, [Q] ADH, [R] Constriction, [S] Decrease
Correct answer
C. [P] Osmoreceptors, [Q] ADH, [R] Constriction, [S] Increase
Step-by-step solution
Excessive fluid loss from the body activates osmoreceptors [P]. These receptors stimulate the hypothalamus to release Antidiuretic Hormone (ADH) or vasopressin [Q] from the neurohypophysis. ADH exerts a constrictory effect (vasoconstriction) [R] on blood vessels, which raises blood pressure. This increase in blood pressure leads to an increase [S] in glomerular blood flow and Glomerular Filtration Rate (GFR). Option 1 is incorrect because osmoreceptors, not chemoreceptors, sense fluid volume changes, and ADH causes