Pls don't just type Book ans.... See.. Here renin is a vasoconstrictor na... Then ANF inhibits aldosteron so., how it facilitates na reabsorbtion..

Incorrect Statement: c. ANF—enhances sodium reabsorption

Explanation:

1. ADH—prevents conversion of angiotensinogen in blood to angiotensin:
- ADH (antidiuretic hormone), also known as vasopressin, is produced by the hypothalamus and released by the posterior pituitary gland.
- Its main function is to regulate water balance in the body by controlling the permeability of the renal collecting ducts to water.
- ADH does not have a direct effect on the conversion of angiotensinogen in the blood to angiotensin. Its primary role is to promote water reabsorption in the kidneys.

2. Aldosterone—facilitates water reabsorption:
- Aldosterone is a hormone produced by the adrenal glands.
- Its main function is to regulate electrolyte and fluid balance in the body, specifically by promoting the reabsorption of sodium ions and the excretion of potassium ions.
- While aldosterone does indirectly affect water reabsorption by promoting sodium reabsorption, its primary action is on sodium and potassium balance rather than water reabsorption.

3. ANF—enhances sodium reabsorption:
- Atrial natriuretic peptide (ANF), also known as atrial natriuretic factor, is a hormone produced by the atria of the heart in response to increased blood volume and pressure.
- Its main function is to promote the excretion of sodium and water by the kidneys, thereby reducing blood volume and pressure.
- ANF acts by inhibiting the reabsorption of sodium in the renal tubules, leading to increased sodium excretion and, consequently, increased water excretion.
- Therefore, the statement that ANF enhances sodium reabsorption is incorrect. It actually promotes sodium excretion.

4. Renin—causes vasodilation:
- Renin is an enzyme released by specialized cells in the kidneys called juxtaglomerular cells.
- Its main function is to initiate the renin-angiotensin-aldosterone system (RAAS), which plays a key role in regulating blood pressure and fluid balance.
- Renin acts on angiotensinogen, a protein produced in the liver, to convert it into angiotensin I.
- Angiotensin I is then converted to angiotensin II by the action of angiotensin-converting enzyme (ACE).
- Angiotensin II is a potent vasoconstrictor, meaning it causes blood vessels to constrict, leading to an increase in blood pressure.
- Therefore, the statement that renin causes vasodilation is incorrect. Renin actually initiates a cascade that ultimately leads to vasoconstriction through the action of angiotensin II.

In summary, the incorrect statement is c. ANF—enhances sodium reabsorption. ANF actually promotes sodium excretion.