Week 10- fluid and electrolyte balance Flashcards
(38 cards)
what is the connection between fat and total body water?
increased body fat decreases the total body water
how does insensible water loss increase? what is it?
increases when the surface of the skin is damaged (burns)
it is water loss through respiratory (skin)
what is the plasma?
non-cellular part of the blood and exchanges substances with the interstitial fluid through the pores of the capillary membranes
which fluid is greater in adults?
ICF is greater than ECF
where is interstitial fluid missing?
between dense connective tissues and bones
transcellular fluid?
portion of total body water contained within epithelial lined spaces.
It is the smallest component of extracellular fluid
importance of body fluids? 4 reasons
- maintains homeostasis
- transport (o2, nutrients, chemical messengers)
- metabolic reactions (water inside the cell is medium for metabolic reactions)
- temperature regulation (water inside the body)
what is osmolarity?
concentration of osmotically active particles (mOsm/L)
increases with dehydration and decreases with overhydration
how is plasma osmolarity altered?
lipidemia, hyperproteinemia (increased concentration of protein in the blood), ketoacidosis (excess blood acids, ketones), DI
what are osmotically active particles?
NaCl, glucose, urea
Increased osmolarity if these substances increase
when do we use plasma osmolality?
when estimating plasma glucose concentrations (DM) and with chronic renal failure (plasma urea is elevated)
what is clinical dehydration?
decreased volume of ECF and increased osmolality
what is hydrostatic pressure?
pushing force exerted by a fluid
higher at arterial end, lower at venous end
what is colloidal osmotic pressure?
pulling force created by plasma proteins, moves fluid back into the capillaries, stronger at the venous end
what is lymph drainage?
fluid is returned to the circulatory system through the lymphatic system
excess fluid and osmotically active plasma proteins that may have leaked into the interstitial are picked up
without lymphatic system excess amount of fluid would accumulate in interstitial fluid
functions of Na+?
- maintains normal body fluid balance and OP
- nerve impulse transmission and muscle contraction
- acid- base balance
how is Na+ regulated?
maintenance of effective circulating volume
- low CV: feedback to increase Na+ and water retention
- baroreceptors
- ANP (excretion)
how is the change in circulating volume measured?
baroreceptors (sensitive to changes in pressure)
- when activated they regulate water elimination by modulating sympathetic NS outflow and ADH secretion
Causes of hyponatremia?
increased ECF volume diarrhea, vomiting addison disease diuretic excess ADH
Causes of hypernatremia?
decrease in ADH (DI)
decreased in water intake
hyper secretion of aldosterone
functions of K+?
maintains body fluid and generates electrical impulse in nerves, muscles
maintains osmotic integrity of the cells (osmotic pressure in ICF)
maintains acid base balance (K+ and H+ exchange)
contribute in reactions
excitability of nerve, skeletal, cardiac, smooth muscle
regulation of K+?
renal mechanism (aldosterone) transcellular shift between ICF and ECF (excess K+ shifted into RBC, muscle, liver, bone) and H+ and K+ exchange between ICF and ECF
causes for hyperkalemia?
(K+ moving out of the cell) insulin deficiency acidosis exercise hyperosmolarity
causes of hypokalemia?
(K+ moving into the cell)
insulin
alkalosis
hypoosmolarity
