Affecting Fluids and Electrolytes

Fluid and Electrolytes

Hormones regulating water retention and loss

ADH (anti-diuretic hormone) * regulates WATER excretion from the kidneys.  As serum osmolality rises (>300), it stimulates osmoreceptors that stimulate thirst to ↑ H2O intake & stimulate ADH release to allow more water reabsorption in the kidney causing dilution of body fluids.  

1. water only, urine will be dark, scant, amber-colored, 
2. alcohol consumption turns ADH off and you are dehydrated the next day
3. ADH & Aldosterone activate in ↓ BP

ADH keeps water from being loss through urination.

Aldosterone * Renin-Angiotensin System * regulates electrolyte balance from the kidneys by promoting Na+ & water retention and K+ loss

1. with low blood volume such as internal bleeding or cut arm, kidneys kick in to reabsorb water
2. this system works with salt to counteract effects of low blood volume & low BP to try to increase BP (water & salt reabsorbed)

Aldosterone, Renin-Angiotensin System keeps water and sodium  from being loss through urination, though Potasium is loss.

ANP (atrial natriuretic peptide) * cardiac hormone found in atria & released when atria are stretched by increasing blood volume or BP (CHF) works to lower BP/volume through vasodilation & suppression of RAS (rennin-angiotensin system)

ANP  is a marker found through testing, signifying CHF. ANP tries to lower BP/Volume that ADH and ARAS creates.