angiotensin

Examples of angiotensin in the following topics:

• Long-Term Renal Regulation

  • Consistent and long-term control of blood pressure is determined by the renin-angiotensin system.
  • A key modulator of blood viscosity is the renin–angiotensin system (RAS) or the renin–angiotensin–aldosterone system (RAAS); a hormone system that regulates blood pressure and water balance.
  • Angiotensin I is subsequently converted to angiotensin II by the enzyme angiotensin converting enzyme found in the lungs.
  • If the renin–angiotensin–aldosterone system is too active, blood pressure will be too high.
  • It is believed that angiotensin I may have some minor activity, but angiotensin II is the major bio-active product.

• Sodium Balance Regulation

  • Extra sodium is lost from the body by reducing the activity of the renin-angiotensin-aldosterone system which leads to increased sodium loss from the body.
  • The major physiological controller of aldosterone secretion is the plasma angiotensin II level which increases aldosterone secretion.
  • A low renal perfusion pressure stimulates the release of renin, which forms angiotensin I which is converted to angiotensin II.
  • In addition to aldosterone and angiotensin II other factors influence sodium excretion.
  • Regulation of sodium via the hormones renin, angiotensin, and aldosterone.

• Nonrespiratory Air Movements

  • ACE (angiotensin converting enzyme) is an enzyme secreted by the endothelial cells of the capillaries in the lungs. 
  • ACE converts angiotensin I into angiotensin II, which are two important hormones in the renin-angiotensin feedback loop of the renal system.
  • In general, more ACE leads to more angiotensin II, which leads to more aldosterone, which leads to more retained water through sodium reabsorption in the kidney, which leads to increased blood volume and blood pressure.
  • The Renin-Angiotensin System is dependent on ACE from the lungs to regulate blood pressure.

• Adrenal Cortex

  • The cortex is regulated by neuroendocrine hormones secreted by the pituitary gland which are under the control of the hypothalamus, as well as by the renin-angiotensin system.
  • The major stimulus to produce aldosterone is angiotensin II while ACTH from the pituitary only produces a transient effect.
  • Angiotensin is stimulated by the juxtaglomerular cells when renal blood pressure drops below 90 mmHg.
  • Its secretion is regulated by the oligopeptide angiotensin II (angiotensin II is regulated by angiotensin I, which in turn is regulated by renin).

• Developmental Changes in Fluids

  • Hormonal mechanisms including the renin-angiotensin system, aldosterone, and vasopressin are involved in modifying fetal renal excretion, reabsorption of sodium and water, and regulation of vascular volume.
  • Overview of the renin-angiotensin system that regulates blood pressure and water (fluid) balance.

• Regulation of Water Output

  • A fluid-insufficiency causes a decreased perfusion of the juxtaglomerular apparatus in the kidneys, activating the renin-angiotensin system.
  • The activated renin-angiotensin system stimulates zona glomerulosa of the adrenal cortex, which in turn secretes hormone aldosterone.
  • Overview of the renin-angiotensin system that regulates blood pressure and water (fluid) balance.

• Overview of the Adrenal Glands

  • The cortex is regulated by neuroendocrine hormones secreted from the pituitary gland which are under the control of the hypothalamus, as well as by the renin-angiotensin system.
  • The major stimulus to produce aldosterone is angiotensin II while ACTH from the pituitary only produces a transient effect.
  • Angiotensin is stimulated by the juxtaglomerular cells when renal blood pressure drops below 90 mmHg.

• Congestive Heart Failure

  • Reduced perfusion (blood flow) to the kidneys stimulates the release of renin – an enzyme that catalyzes the production of the potent vasopressor angiotensin .
  • Angiotensin and its metabolites cause further vasoconstriction, and stimulate increased secretion of the steroid aldosterone from the adrenal glands.
  • Reduced perfusion (blood flow) to the kidneys stimulates the release of renin, an enzyme that catalyzes the production of the potent vasopressor angiotensin.

• Regulation of Water Intake

  • Renin cleaves the zymogen angiotensinogen, always present in plasma as a result of constitutive production in the liver, into a second inactive form, angiotensin I, which is then converted to its active form, angiotensin II, by angiotensin converting enzyme (ACE), which is widely-distributed in the small vessels of the body.
  • Angiotensin II exerts systemwide effects, triggering aldosterone release from the adrenal cortex, direct vasoconstriction, and thirst behaviors originating in the hypothalamus.

• Local Regulation of Blood Flow

  • A number of hormones influence arteriole tone such as the vasoconstrictive epinephrine, angiotensin II and  endothelin and the vasodilators bradykinin and prostacyclin.