Essential exam RAAS flashcard

This table compares four critical hormones that work together to maintain stable fluid levels and blood pressure in the body.

Hormone	Chemical Structure	Source (Where it's Made/Activated)
Angiotensin II (Ang II)	Protein (8 amino acids); Water-soluble	Primarily active in the blood. It's created when the liver product, Angiotensinogen, is cut by two different enzymes (Renin and ACE).
Antidiuretic Hormone (ADH)	Protein (9 amino acids); Water-soluble	Produced by the Hypothalamus (in the brain) and stored in the Posterior Pituitary Gland (at the base of the brain).
Aldosterone (ALDO)	Steroid (Lipid-soluble)	Produced by the outer layer (zona glomerulosa) of the Adrenal Cortex (the outer part of the adrenal gland, on top of the kidney).
Atrial Natriuretic Peptide (ANP)	Protein (28 amino acids); Water-soluble	Made in the Atrial Chambers (upper chambers) of the Heart.

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These sections explain the trigger for each hormone's release and its specific effects on the body.

Trigger for Release	Primary Target Organs and Actions	Net Result on the Body
Low blood pressure or Sympathetic Nervous System activity (e.g., during stress or bleeding). This leads to the kidney releasing Renin.	Blood Vessels: Causes powerful vasoconstriction (narrowing the vessels) to increase blood pressure immediately. Kidney: Causes the kidney to reduce urine output (by decreasing filtration rate) to keep water in the body. Hypothalamus: Stimulates the hypothalamus, which then signals the release of ADH from the pituitary. Adrenal Cortex: Stimulates the release of Aldosterone.	Increased Blood Pressure and Increased Blood Volume by keeping fluid in the body and constricting vessels.
Related Disorders: Blood pressure homeostasis (maintaining stability).

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Trigger for Release	Primary Target Organs and Actions	Net Result on the Body
The Hypothalamus sends a nerve signal to the pituitary, triggered by: Angiotensin II in the blood. Increased blood osmolarity (blood is too concentrated/salty). Decreased nerve signals from stretch receptors in the atria and carotids (signals that blood volume is low).	Kidney: Causes the kidney to decrease H2O excreted in urine (keeps water in the body). Third Center in Hypothalamus: Stimulates a sensation of Thirst. Blood Vessels: Causes vasoconstriction (narrowing) to raise blood pressure (this is why it is sometimes called Vasopressin).	Increased retention of water, maintaining blood volume and blood pressure.
Related Disorders: Diabetes Insipidus (a condition where too little ADH is released, leading to excessive urination).

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Trigger for Release	Primary Target Organs and Actions	Net Result on the Body
Primarily stimulated by Angiotensin II and by increased K+ (Potassium) concentration in the blood.	Kidney: Decreases Na+ and H2O excreted in urine (keeps salt and water in the body). Increases K+ excretion (gets rid of potassium). Note: The effects on H+ excretion are complex and conditional.	Maintenance of Na+ and blood K+ levels, maintaining blood volume and pressure by decreasing urine output.
Related Disorders: Hyperaldosteronism (too much Aldosterone) and Hypoaldosteronism (too little Aldosterone).

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Trigger for Release	Primary Target Organs and Actions	Net Result on the Body
Increased stretch of atrial wall (when blood volume and pressure are too high).	Kidney: Increases Na+ and H2O excreted in urine (gets rid of fluid). Inhibits the release of Renin. Blood Vessels: Causes vasodilation (widening the vessels) to decrease vascular resistance. Hypothalamus/Adrenal: Inhibits the release of ADH and Aldosterone.	Increased urine output, leading to decreased resistance, decreased blood volume, and decreased blood pressure.
Related Disorders: Blood pressure homeostasis (maintaining stability).