renin-angiotensin system

(noun)

A collection of hormones involved in the regulation of the body's blood pressure and water content.

Related Terms

Examples of renin-angiotensin system 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.
    • Plasma renin then carries out the conversion of angiotensinogen released by the liver to angiotensin I.
    • If the renin–angiotensin–aldosterone system is too active, blood pressure will be too high.
    • The figures outlines the origination of the renin-angiotensin pathway molecules, as well as effects on target organs and systems.

  • Regulation of Water Intake

    • Another way through which thirst is induced is through angiotensin II, one of the hormones involved in the renin-angiotensin system.
    • The renin-angiotensin system is a complex homeostatic pathway that deals with blood volume as a whole, as well as plasma osmolarity and blood pressure.
    • When the macula densa is stimulated by high osmolarity, The JGA releases renin into the bloodstream, which cleaves angiotensinogen into angiotensin I.
    • Note that the renin-angiotensin system, and thus thirst, can be caused by other stimuli besides increased plasma osmolarity or a decrease in blood volume.
    • Sympathetic nervous system stimulation and low blood pressure in the kidney's (decreased GFR) will stimulate the renin-angiotensin system as well, and will also cause an increase in thirst.

  • Regulation of Water Output

    • The hormones ADH (anti-diuretic hormone, also known as vasopressin) and aldosterone, a hormone created by the renin-angiotensin system play a major role in this.
    • Aldosterone is a steroid hormone (corticoid) produced at the end of the renin-angiotensin system.
    • To review the renin-angiotensin system, low blood volume activates the juxtaglomerular apparatus in a variety of ways, which secretes renin.
    • Renin cleaves angiotensin I from the liver produced angiotensinogen.
    • Overview of the renin-angiotensin system that regulates blood pressure and plasma osmolarity.

  • Other Hormonal Controls for Osmoregulation

    • The renin-angiotensin-aldosterone system (RAAS) stabilizes blood pressure and volume via the kidneys, liver, and adrenal cortex.
    • The renin-angiotensin-aldosterone system (RAAS) is a hormone system that regulates blood pressure and water (fluid) balance .
    • This system proceeds through several steps to produce angiotensin II, which acts to stabilize blood pressure and volume.
    • After renin facilitates the production of angiotensis I, angiotensin converting enzyme (ACE) then converts angiotensin I to angiotensin II.
    • The renin-angiotensin-aldosterone system increases blood pressure and volume.

  • 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.
    • The hypothalamic-neurohypophysial system plays a fundamental role in the maintenance of body fluid homeostasis by secreting arginine vasopressin (AVP) and oxytocin (OT) in response to a variety of signals, including osmotic and non-osmotic stimuli.
    • This provides evidence for a functional link between the development of central cholinergic mechanisms and hypothalamic neuropeptide systems in the fetus.
    • Overview of the renin-angiotensin system that regulates blood pressure and water (fluid) balance.

  • 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.
    • A low renal perfusion pressure stimulates the release of renin, which forms angiotensin I which is converted to angiotensin II.
    • The perfusion pressure to the adrenal gland has little direct effect on aldosterone secretion and the low blood pressure operates to control aldosterone via the renin angiotensin system.
    • 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.
    • The epithelial cells and macrophages of the lungs secrete many molecules that have immune system functions.
    • They can damage and inhibit pathogens and are considered a barrier component of the immune system.
    • The renin-angiotensin-aldosterone 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).

  • Hormonal Regulation of the Excretory System

    • When blood pressure drops, the renin-angiotensin-aldosterone system (RAAS) is activated.
    • When angiotensinogen is cleaved by renin, it produces angiotensin I, which is then converted into angiotensin II in the lungs.
    • Angiotensin II stimulates release of these hormones.
    • Angiotensin II, in turn, is formed when renin cleaves angiotensin.
    • Explain how the actions of different hormones regulate the excretory system

  • Congestive Heart Failure

    • Binding to alpha-1 receptors results in systemic arterial vasoconstriction.
    • 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.