Physiology · Cardiovascular System

JGA-renin-angiotensin system as integrated cardiovascular-renal regulation

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Definition

  • The renin-angiotensin system is a hormonal mechanism of blood pressure regulation: a fall in blood pressure triggers renin release from the juxtaglomerular (JG) cells of the kidney, initiating a cascade that ends in angiotensin II.

Formation of Angiotensin II

  • Step 1 Fall in blood pressure stimulates renin release from the JG cells of the kidney.
  • Step 2 Renin converts angiotensinogen to angiotensin I.
  • Step 3 Angiotensin-converting enzyme (ACE) converts angiotensin I to angiotensin II.

Cardiovascular Action: Short-term Regulation

  • Angiotensin II is a potent vasoconstrictor that raises blood pressure, the short-term regulatory arm of this system.