Term
Where is aldosterone secreted from?
What are its 3 major inputs causing its release?
What is its action? |
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Definition
Adrenal cortex.
1. Adrenocorticotropic hormone (ACTH)
2. Increased plasma potassium.*
3. Angiotensin II*
Increases passive Na channels in the collecting tubule, concentrating urine and conserving water by absorbing Na. Also increases activity of Na+/K+ pumps to promote Na+ reabsorption. Can cause hypokalemia. |
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Term
| Describe the processes that may take place when a person is suffering from dehydration to restore homeostasis. |
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Definition
1. Extracellular volume drops, osmolarity rises.
2. The carrotid barroreceptors pick up a drop in volume and fire less frequently, causing a sympathetic response. These receptors also cause the release of ADH from the hypothalamus (down the posterior pituitary).
3. Additionally, intrarenal baroreceptors and osmoreceptors pick up this change, causing decreased GFR.
4. The release of norepinephrine on the kidney and the response of these receptors causes renin release from JG cells which converts ANGI to ANGII. This causes afferent/efferent constriction increasing the filtration fraction.
5. Increased ANGII also increases thirst to help in the restoration of fluid. The ADH mentioned earlier helps in water retention in the collecting tubules.
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Term
| With the presence of ANGII, what other hormones are also elicited directly by ANGII? |
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Definition
Aldosterone (Adrenal cortex)
ADH (hypothalamus)
Additionally, the thirst response of the hypothalamus is due to the action of ANGII. |
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Term
| What three factors account for the "escape" of primary hyperaldosteronism? |
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Definition
1. GFR rises
2. Decreased renal sympathetic activity
3. Decreased ANGII levels |
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Term
| What organ responds to increased K+ in the blood? What does it do and what is the mechanism? |
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Definition
| The Adrenal Cortex senses the potassium and releases aldosterone which, in addition to increasing sodium reabsorption in the collecting tubule, also increases potassium excretion in principal cells. |
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Term
| What is a primary problem to be concerned with in a person who is vomiting frequently? |
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Definition
| Causes alkalosis which can induce hypokalemia. |
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Term
This type of acidosis/alkalosis is associated with changes in potassium levels:
A) Metabolic acidosis/alkalosis
B) respiratory acidosis/alkalosis |
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Definition
| A) Metabolic acidosis/alkalosis |
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Term
| During hypocalcemia, what hormone is released and where does it act in the kidney? |
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Definition
| PTH; acts on the distal convoluted tubule. |
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