Lenin and Giotene New World
The renin-angiotensin system or the renin-angiotensin-aldosterone system is an endocrine system pathway that regulates the volume of blood pressure and extracellular fluid. When the amount of blood to the kidneys is small, glomerular neurons in the nephron's imported arterioles activate prolarenin and secrete renin into blood. Renin in blood converts angiotensinogen produced in the liver to angiotensin I. Angiotensin I is converted to angiotensin II by the angiotensin converting enzyme present in the endothelium of the lungs and the whole body. Angiotensin II contracts blood vessels to increase blood pressure and stimulates aldosterone secretion in the adrenal cortex. Aldosterone increases sodium and water reabsorption in the kidneys. Increases in blood sodium and water increase total body fluid and blood pressure. When the renin-angiotensin-aldosterone system is abnormally activated, blood pressure increases. Drugs that lower blood pressure by disturbing each phase of this system have been developed and used to treat hypertension, heart failure, kidney failure, and diabetes.