Examkin

Question

Difficulty: HardHuman Physiology, Health, and Diseases

Human renal physiology involves precise filtration, reabsorption, and hormonal regulation to maintain fluid and electrolyte homeostasis. Which of the following statements regarding renal function and associated metabolic disorders are correct?

  1. Atrial Natriuretic Factor (ANF) acts as a antagonist to the renin-angiotensin mechanism by causing vasodilation and reducing blood pressure.Answer
  2. B
    Diabetes insipidus is caused by hyposecretion of insulin from the beta cells of the pancreas, leading to severe glucosuria.
  3. The descending limb of the Loop of Henle is permeable to water but almost impermeable to electrolytes, concentrating the filtrate as it moves toward the renal medulla.Answer
  4. D
    Aldosterone is secreted by the adrenal medulla and directly stimulates sodium reabsorption in the proximal convoluted tubule.

Answer

The correct statements are that Atrial Natriuretic Factor (ANF) acts as an antagonist to the renin-angiotensin mechanism to lower blood pressure, and that the descending limb of Henle's loop is permeable to water while remaining impermeable to electrolytes.
Atrial Natriuretic Factor antagonizes renin-angiotensin pathways to lower blood pressure, and the descending limb of Henle's loop allows passive reabsorption of water while remaining impermeable to electrolytes. Both reflect accurate human renal physiological mechanisms.

Step-by-Step Solution

1
Analyze the endocrine regulation of renal hemodynamic pressure.
Atrial Natriuretic Factor (ANF) is secreted during elevated atrial stretch, inducing vasodilation and natriuresis, directly opposing the vasoconstrictive and sodium-retaining actions of the renin-angiotensin-aldosterone system.
This confirms that ANF functions as a physiological counter-regulatory hormonal brake.
2
Differentiate between Diabetes Mellitus and Diabetes Insipidus etiology.
Diabetes insipidus involves impaired production or action of Antidiuretic Hormone (ADH), resulting in polyuria without glucose loss, whereas insulin dysregulation causes Diabetes mellitus.
This identifies the statement linking insulin hyposecretion to Diabetes insipidus as incorrect.
3
Evaluate Henle's loop counter-current mechanism permeability rules.
The descending limb is thin and selectively permeable to water via aquaporins while restricting ions, concentrating fluid as it descends deeper into the renal medulla.
This verifies the physiological description of descending limb permeability.
4
Examine the origin and site of action of Aldosterone.
Aldosterone is synthesized in the adrenal cortex (zona glomerulosa) and functions at distal nephron segments (DCT and collecting ducts), not the adrenal medulla or proximal tubule.
This refutes the statement regarding Aldosterone's anatomical origin and target tubules.

Key Concept

Renal Osmoregulation, Counter-current Physiology, and Endocrine Control
Rate this question

Topics

Human Physiology, Health, and Diseases

More questions from this topic