Describe other hormones and their functions: - Renin.

Renin is an enzyme produced and released by the kidneys in response to low blood pressure or low blood volume. Its primary function is to regulate blood pressure by initiating a series of reactions that ultimately lead to the production of angiotensin II, a hormone that causes blood vessels to constrict and stimulates the release of aldosterone, a hormone that helps regulate sodium and water balance in the body. Renin also plays a role in the renin-angiotensin-aldosterone system, which helps maintain blood pressure and fluid balance in the body.

Renin

Function:

- Stimulates the production of angiotensin I from angiotensinogen, which is a precursor protein.

Mechanism:

- Renin is released from the kidney's juxtaglomerular apparatus in response to various stimuli, including:
- Decreased blood pressure
- Decreased blood volume
- Increased sympathetic nerve activity
- Renin acts on angiotensinogen in the blood to produce angiotensin I.
- Angiotensin I is then converted to angiotensin II by angiotensin-converting enzyme (ACE).

Effects of Angiotensin II:

- Vasoconstriction: Angiotensin II causes constriction of blood vessels, increasing blood pressure.
- Aldosterone release: Angiotensin II stimulates the release of aldosterone from the adrenal glands. Aldosterone promotes the reabsorption of sodium and water in the kidneys, helping to restore blood volume.
- Sympathetic nerve stimulation: Angiotensin II activates the sympathetic nervous system, which further increases blood pressure and heart rate.
- Thirst stimulation: Angiotensin II stimulates the thirst response in the hypothalamus, encouraging fluid intake and increasing blood volume.