L4 - Body Fluids Flashcards
(22 cards)
why are body fluids important
- primary transport system between cells
- large part of internal environment
- fluid composition critical for cell function
how much does 1L of water weigh in kg
1kg
how many litres total body water (TBW) for average 70kg male
42L - 60% of body mass
what is boundary of interstitial fluid / intracellular fluid
cell membrane
what is permeability of interstitial fluid / intracellular fluid
selectively permeable - ion pumps
what is boundary of interstitial fluid/ plasma
capillary wall
what is permeability of interstitial fluid/plasma
permeable to small molecules
what is osmosis
when water moves from a lower to higher solute concentration
the movement is passive
what is tonicity
the effect of solute concentration on cell volume
what is a hypotonic solution
cell gains water - swells
what is a hypertonic solution
cell loses water - shrinks
what does the lymphatic system do
returns lymph to the cardiovascular system
where does lymph re-enter
it re-enters circulation near the right atrium
what happens when outward pressure is greater than inward pressure
fluid leaves the capillary and enters interstitial fluid
what is colloid OP
osmotic pressure of plasma proteins
what occurs during liver failure in capillaries
- fall in plasma proteins
- colloid OP falls
- reduced inward flow
- Oedema
where is plasma regulated
kidney
what is interstitial fluid
the environment for all cells
what are regulated for water balance
fluid intake and urine output
what is total body water composed of
intracellular fluid and extracellular fluid
what is extracellular fluid composed of
plasma and interstitial fluid
what does the presence of plasma proteins do
exert an inward osmotic force
