RAAS

• What cells in the kidney are responsible for releasing renin?

  Juxtaglomerular cells
• What is the first product formed after renin is released?

  Angiotensin I
• What are the sensors that detect blood pressure changes in the RAAS?

  Baroreceptors
• What is one of the effects of Angiotensin II on the hypothalamus?

  It stimulates thirst
• What triggers the activation of the RAAS?

  ↓ Blood pressure
• What is the overall effect of the RAAS on blood volume and pressure?

  ↑ Blood volume/pressure
• What are the effects of ANP on the RAAS?

  • Inhibits ENaC channels in principal cells
  • Blocks renin release
  • Decreases sodium reabsorption in the collecting duct
  • Counteracts the effects of RAAS
• What is the first product formed after renin is released?

  Angiotensin I
• What is the effect of aldosterone on the distal convoluted tubule (DCT)?

  ↑ Water/Sodium retention
• What does ADH stand for?

  Antidiuretic hormone
• What triggers the activation of the RAAS?

  ↓ Blood pressure
• What does ADH stand for?

  Antidiuretic hormone
• What triggers the release of ANP?

  ↑ ECF → ↑ Venous → Atria stretches
• How does ANP affect sodium reabsorption in the collecting duct?

  It decreases sodium reabsorption
• What are the main components of the RAAS pathway?

  • Renin release from juxtaglomerular cells
  • Conversion of angiotensinogen to angiotensin I
  • Conversion of angiotensin I to angiotensin II by ACE
  • Effects of angiotensin II: vasoconstriction, thirst stimulation, aldosterone release
  • Aldosterone promotes sodium and water retention
• What are the factors affecting renin release?

  • ↓ Na/Cl levels
  • ↓ Renal perfusion
  • ↑ Sympathetic stimulation
  • ↓ ANP and ↓ BNP
• What effect does Angiotensin II have on systemic arterioles?

  It causes vasoconstriction
• Which organ produces angiotensinogen?

  Liver
• What is the role of Atrial Natriuretic Peptide (ANP) in the RAAS?

  It inhibits ENaC channels in principal cells
• What does RAAS stand for?

  Renin, Angiotensin, Aldosterone System
• What is the role of Atrial Natriuretic Peptide (ANP)?

  Inhibits ENaC channels in principal cells
• What is the relationship between sodium levels and extracellular fluid (ECF) volume?

  ↓ Na → ↓ ECF
• What are the sensors that detect blood pressure changes in the body?

  Baroreceptors
• What is the sequence of events in the RAAS pathway starting from low blood pressure?

  1. ↓ Blood pressure detected by baroreceptors
  2. Liver releases angiotensinogen
  3. Kidney juxtaglomerular cells release renin
  4. Renin converts angiotensinogen to angiotensin I
  5. ACE in lungs converts angiotensin I to angiotensin II
  6. Angiotensin II causes vasoconstriction and stimulates thirst
  7. Aldosterone is released, increasing sodium/water retention
  8. ↑ Blood volume/pressure