Renin-angiotensin system (RAS) is an important humoral regulation system composed of a series of peptide hormones and corresponding enzymes. Its main function is to regulate and maintain the balance of blood pressure, water and electrolyte, and maintain the relative stability of the internal environment of the human body. Renin-angiotensin system is an important mechanism involved in the pathogenesis of hypertension under pathological conditions.
Renin-angiotensin system has a variety of dual regulatory effects and homeostatic regulatory functions inside and outside the system, which can not only promote tissue reconstruction, but also have the effect of disease-resistant rational reconstruction. It not only plays an important role in hypertension, kidney disease, myocardial hypertrophy and other diseases, but also has an important pathological role in almost all cardiovascular and cerebrovascular diseases.
Extended information:
Composition and function of renin-angiotensin system:
1. Renin-angiotensin system exists not only in circulatory system, but also in vascular wall, heart, center, kidney and adrenal gland.
The components of renin-angiotensin system mainly include renin, angiotensin converting enzyme (ACE), angiotensinogen and angiotensin II, and various organs and tissues such as myocardium, vascular smooth muscle, skeletal muscle, brain, kidney and gonad are rich in angiotensin converting enzyme and angiotensin II receptor.
In addition to systemic renin-angiotensin system, there are relatively independent local renin-angiotensin systems in cardiovascular organs and tissues, which can regulate cardiovascular activities more directly and more importantly through paracrine and/or autocrine.
2. Renin secreted by renal peribulbar cells can transform angiotensinogen in blood into inactive angiotensin ⅰ, which forms angiotensin ⅱ with 8 peptides and angiotensin ⅲ with 7 peptides under the action of angiotensin converting enzyme.
Angiotensin plays a significant role in maintaining the balance of blood pressure and blood volume. It can increase blood pressure by contracting the smooth muscle of arterioles, promoting the release of vasopressin and oxytocin from neurohypophysis, strongly stimulating the secretion of aldosterone from adrenal cortex, promoting renal tubules to reabsorb water and sodium, and exciting sympathetic nerves. It is the most effective antihypertensive substance known at present.
3. The role of local renin-angiotensin system in the heart is mainly positive inotropic effect on the heart, causing myocardial hypertrophy, regulating coronary artery resistance and inhibiting the growth of myocardial cells. The role of local renin-angiotensin system in blood vessels is mainly to relax and contract blood vessels, which affects the structure of blood vessels and the function of coagulation system.
Baidu encyclopedia -RAS system