Flashcards in Chapter 17 Fluids: Med Surg Deck (56)
what does water content vary with?
gender, age, body mass
percentage of body weight of water greater in men or women?
who would have more water content as compared to body weight?
2/3 of body water and 40% of body weight
1/3 of body water, consisits of intravascular, interstitial and transcellular spaces
1/3 of ECF located here as plasma
2/3 of ECF
1 L of ECF; CSF, fluid in GI, pleural, synovial, peritoneal fluid
why is body water needed?
fluids are in constant motion and transport nutrients, electrolyes, oxygen, regulate temperatures, lubricate joints and membranes, and aids digestion
how much does 1 L of fluid weigh?
molecules dissociate (split into ions) when placed in water
electrically charged particles
positive charged ions
negative charged ions
electrical charge of an ion
movement of molecules from an area of high concentration to one of low concentration; membrane must be permeable; no energy
same as diffusion, but some molecules diffuse slowly into the cell and need some help so a carrier molecule accelerates the rate; no energy
molecules move against the concentration gradient, external energy is required; e.g. sodium potassium pump: potassium in and sodium out
water movement through a semipermeable (favors water not solutes) membrance from an area of low solute concentration to an area of high solute concentration; no external energy, stops when equal
describes fluids (water balance) inside the body, typically performed to evaluate the concentration of plasma in urine
normal plasma osmolality
increased plasma osmolality
concentration is too high or water is too low aka water deficit -> dehydrated
decreased plasma osmolality
concentration is too low or water is too high aka water excess
major determinant of plasma osmolality
sodium and glucose
ECF and ICF are:
isotonic to each other, hence no movement of water occurs and no gain or loss of water occurs although ECF expands e.g. lactated ringers, 0.5% saline