The Renin-Angiotensin-Aldosterone system is a hormone system in our bodies that increases blood pressure

The Renin-Angiotensin-Aldosterone system is a hormone system in our bodies that increases blood pressure. It has many steps. When the kidneys detect lower blood flow they convert prorenin to renin in the bloodstream. Renin changes angiotensin, from the liver, to angiotensin I. Angiotensin I is changed into angiotensin II by the angiotensin-converting enzyme (ACE) in the lungs. Angiotensin II is a powerful vasoconstrictor. It causes blood vessels to constrict. Angiotensin II also causes the release of aldosterone from the adrenal cortex. Aldosterone causes the kidneys to increase the amount of sodium and water into the bloodstream. This increase in blood volume increases blood pressure.
If any of the above steps is interrupted or altered, then blood pressure will increase. High blood pressure, hypertension, can cause damage to your body or even death. Hypertension can damage the lining of blood vessels which can make them less elastic. Fats may cling to these damaged areas and cause a heart attack or stroke if the vessels are blocked. Blood vessels can also become weak from hypertension and rupture causing an aneurysm. Clogged or restricted blood vessels in the heart can lead to coronary artery disease an enlarged heart or heart failure, all of which can cause ill health effects and eventually death. If blood flow is restricted to the brain it can cause a stoke or transient ischemic attack (TIA) or mini-stroke. A form of dementia caused by hypertension can lead to cognitive deficits, loss of vision or paralysis. Hypertension can also damage the blood vessels in your kidneys. In fact, it is one of the most common causes of kidney failure.
High blood pressure is very dangerous, so it is important that the Renin-Angiotensin-Aldosterone system is in good working order. Some medications like ACE inhibitors interfere with the RAA system to reduce blood pressure.