RAAS Flashcards
(23 cards)
Which organ produces angiotensinogen?
Liver
What stimulates the kidney to release renin?
Low renal perfusion pressure and sympathetic stimulation via β1 receptors
Which neurotransmitter stimulates renin release from the kidney?
Norepinephrine (NE)
Which receptor on the juxtaglomerular cells responds to sympathetic stimulation?
β1-adrenergic receptor
What does renin convert angiotensinogen into?
Angiotensin I
Where is angiotensin-converting enzyme (ACE) primarily found?
Pulmonary endothelium (lungs)
What does ACE convert angiotensin I into?
Angiotensin II
Which receptor does angiotensin II bind to on blood vessels to cause vasoconstriction?
AT1 receptor
What is the effect of angiotensin II on the adrenal cortex?
Stimulates aldosterone secretion
What is the effect of aldosterone on the kidneys?
Increases Na⁺ and Cl⁻ reabsorption, K⁺ excretion, and water retention
Which part of the nephron does aldosterone act on?
Distal tubule and collecting duct
What hormone is released from the posterior pituitary in response to angiotensin II?
Antidiuretic hormone (ADH or vasopressin)
What is the effect of ADH on the kidneys?
Increases water reabsorption in the collecting ducts via aquaporins
Which receptors does ADH act on in the kidney?
V2 receptors
Which receptors does ADH act on for vasoconstriction?
V1 receptors
What is the overall effect of the RAAS system on blood pressure?
Increases blood pressure and blood volume
How does the autonomic nervous system amplify RAAS activity?
Sympathetic stimulation enhances renin release and vasoconstriction
What feedback mechanism inhibits further RAAS activation?
Restoration of renal perfusion and blood volume
What ions are reabsorbed under the influence of aldosterone?
Sodium (Na⁺) and chloride (Cl⁻)
What ions are excreted under the influence of aldosterone?
Potassium (K⁺) and hydrogen ions (H⁺)
How does aldosterone cause sodium reabsorption?
By upregulating epithelial sodium channels (ENaC) and Na⁺/K⁺-ATPase in the distal nephron
What effect does aldosterone have on potassium balance?
Increases potassium excretion by enhancing K⁺ secretion into the tubular lumen
What is the consequence of prolonged aldosterone activation on acid-base balance?
Metabolic alkalosis due to increased H⁺ excretion
