Fluid, Electrolyte, Acid-Base Balance Flashcards
Least hydrated tissue in body
- adipose tissue
2 main fluid (water) compartments
- intracellular fluid (ICF) 2/3
- extracellular fluid (ECF) 1/3
Extracellular fluid (water) compartment
(1) 20% plasma (fluid portion of blood)
(2) 80% interstitial fluid (fluid in spaces between tissue cells)
Bonds in nonelectrolytes
- covalent bonds
- do not dissociate in solutions
examples of nonelectrolytes
- organic molecules like glucose, lipids, creatinine and urea
electrolytes
- dissociate into ions in water
- can conduct electric current
- inorganic salts, acids and bases, some proteins
what releases ADH
- posterior pituitary
what releases aldosterone
- adrenal cortex
Purpose of antidiuretic hormone
- conserves water: promotes water reabsorption by collecting ducts in kidneys
- in response to increased sodium concentration in plasma and increased ECF osmolality
Purpose of aldosterone
- affects kidney tubules to increase Na+ reabsorption and K+ secretion
- in response to increased K+ conc in ECF and decreased Na+ content
opposite effect of ADH
- aldosterone
Influence of atrial natriuretic peptide
- released in heart
- reduces blood pressure and blood volume by inhibiting vasoconstriction, Na+ and water retention
- makes collecting ducts reabsorb more H2O; decrease Na+ reabsorption
Hormone that reduces BP and BV
- atrial natriuretic peptide (ANP) released by cardiac muscle cells
Female sex hormones and water regulation
- estrogens: like aldosterone, enhance NaCl reabsorption by renal tubules
- progesterone: decrease Na+ reabsorption
Hormones that enhance tubular reabsorption of Na+
- aldosterone
- estrogen (female sex hormone)
- glucocorticoids (cortisol)
In response to which, is ANP released?
- stretch of atria of heart due to increased blood pressure
Which hormone regulates ECF calcium ion levels?
- parathyroid hormone (PTH) stimulated by declining Ca2+ in plasma
- promotes increase in blood calcium
Hormone that increases blood calcium
- PTH
Which organs does PTH target?
- bones, kidneys and small intestine
How does PTH affect bones?
- activate bone-digesting osteoclasts
- osteoclasts break down the bone matrix
- release Ca2+ and HPO4- to blood
How does PTH affect kidneys?
- increases Ca2+ reabsorption by kidney tubules/ decreases phosphate ion reabsorption
How does PTH affect small intestine?
- enhances intestinal absorption of Ca2+ by stimulating kidneys to activate vitamin D
