Question

1. How is cortisol involved in fluid balance?

2. What type of hormone is ANP? ANP is a peptide hormone, regulating the blood pressure.

3. Does ANP cause an increase or decrease in blood volume and B/P and how?

4. How can the nurse promote the release of ANP?

5. How is the ANP hormone involved in fluid balance?

6. How does the thirst mechanism control fluid balance?

7. Which organ controls thirst and how?

8. What is the BNP hormone and how is it involved in fluid balance?

Answer 1

1. It's a steroid hormone. Almost every cell contains receptors for cortisol and so cortisol can have lots of different actions depending on which sort of cells it is acting upon. These effects include controlling the body's blood sugar levels and thus regulating metabolism, acting as an anti-inflammatory, influencing memory formation, controlling salt and water balance, influencing blood pressure and helping development of the foetus. Cortisol maintains fluid balance by negative feedback .

When cortisol levels in the blood are low, a group of cells in a region of the brain called the hypothalamus releases CRH, which causes the pituitary gland to secrete another hormone, adrenocorticotropic hormone, into the bloodstream. High levels of ACTH hormone are detected in the adrenal glands and stimulate the secretion of cortisol, causing blood levels of cortisol to rise. As the cortisol levels rise, they start to block the release of CRH from the hypothalamus and ACTH hormone from the pituitary. As a result the ACTH hormone levels start to drop, which then leads to a drop in cortisol levels.

2. ANP is a peptide hormone . Atrial Natriuretic Peptide (ANP)

Function: Antagonist to RAAS, increase urine output so: decrease systemic resistance, H2O and Na, decrease BV and BP.

3. ANP decreases blood volume and BP by acting as a antagonist to RAAS , increasing urine output , decreases systemic resistance ,water and H2O .

4. ANP is released by cardiac myocytes in response to atrial distension. ANP acts to oppose this system by causing vasorelaxation, blocking the secretion and sodium-retaining effects of aldosterone, and inhibiting renal renin secretion and hence involved in fluid balance .