Question

Question #1a755

Answer 1

The RAAS system works in response to low blood pressure and blood volume.

Explanation:

The renin-angiotensin aldosterone system (RAAS) regulates blood pressure and blood volume in the body. A drop in blood pressure is sensed by baroreceptors in blood vessels which then signal the brain to initiate the release of renin.

Renin is a hormone which acts like an enzyme. It is released by the juxtaglomerular cells of the kidney. Upon release, renin will help cleave the zymogen, angiotensinogen (which was released by the liver) into angiotensin I.

Angiotensin I will then travel to the lungs where another enzyme, Angiotensin Converting Enzyme (ACE), will help cleave it into angiotensin II .

Angiotensin II will function to stimulate the release of aldosterone from the adrenal glands. Aldosterone is a hormone which functions to reabsorb `Na^(+1)` ions where water will passively follow, increasing blood volume and blood pressure and to secrete `K^(+1)` ions. Angiotensin II also has other effects in the body such as acting as a vasoconstricte on arterioles to help raise the arterial blood pressure and helping to release antidiuretic hormone (ADH) from the posterior pituitary gland.