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Aldosterone Deanna Page.

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Presentation on theme: "Aldosterone Deanna Page."— Presentation transcript:

1 Aldosterone Deanna Page

2 SYNTHESIS Aldosterone is synthesized by the cells of the Zona Glomerulosa of the Adrenal Cortex in the Adrenal Gland, located above the Kidneys.

3 STRUCTURE C21H28O5 A steroid hormone, class of corticosteroids (steroid produced in the adrenal cortex), main mineralocorticoid (class of corticosteroid, produced in the adrenal cortex)


5 REGUALTION AND ACTION Synthesis of aldosterone is stimulated by
elevated levels of blood potassium Angiotensin II, a product of the renin-angiotensin-aldosterone system. Directly stimulates the reabsorption of sodium and the excretion of potassium by principal cells of the distal tubule and the collecting duct.  indirectly influences blood pressure, blood volume, and water retention.

6 Renin Angiotensin Aldosterone Pathway

7 Create Na+/K+ pump to drive K+ ions into the principal cell of collective duct.
Creates K+ channels on the apical surface of the principal cell to allow K+ to flow through passive transport to the urine Creates Na+ channels on the apical surface of the principal cell to allow Na+ from the urine into the principal cell, then through the Na+/K+ pump into the blood. High concentration of Na+ in blood causes osmosis to occur, so water from the urine will come into the blood Increased stroke volume = Increased blood pressure

8 Goal: Bring in Na+ from urine into the bloodstream through different channels

9 How do leftover protons escape cell?
Proton pump Sodium proton pump Potassium proton pump H+ H+ H2O + CO2 → H2CO3 ⇒ H+ + HCO3- Na+ Stimulates secretion of H+, rremoves excess protons from blood H+ K+ Goal: Get rid of leftover protons in alpha intercalated cell through pumps that also power the aldosterone pathway to increase blood pressure

10 Juxtaglomerular (JG) cells = primary site of renin storage and release
reduction in afferent arteriole pressure  release of renin from the JG cells increased pressure  inhibits renin release. Specialized cells (macula densa) = senses the concentration of sodium and chloride ions in the tubular fluid NaCl is elevated in the tubular fluid  inhibits renin release reduction in tubular NaCl  stimulates renin release by the JG cells

ALDOSTERONE RECEPTOR It belongs to the nuclear receptor family where the ligand diffuses into cells, interacts with the receptor and results in a signal transduction affecting specific gene expression in the nucleus.

Low Levels of Aldosterone: --dehydration, low blood pressure, a low blood sodium level, and a high potassium level, high pulse symptoms of fatigue and often salt-craving, “cognitive fuzziness”, dizziness or lightheadedness on standing, or palpitations High Levels of Aldosterone: --increases reabsorption of sodium and loss of potassium by the kidneys, low potassium level, high blood pressure symptoms include headache and muscle weakness, especially if potassium levels are very low


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