Renal: Compartments Flashcards
humans are X% water
50-60% water
water in fat vs water in muscle
more in muscle, less in fat
water ratio in women vs men
women have more fat, so less water
water ratio in older vs younger
older ppl have more fat, so less water
what ratio in chronic illness vs healthy
chronic has less muscle, so less water
what happens to male / female water content as age increase
as age goes up, you have less water (more fat) – but, the change for men is less drastic than the change in women
where are the three spots that water is located in the body
intracellular, extracellular (interstitial and intravascular)
of all the total body fluid how much is ICF? ECF? interstitial? plasma?
2/3 is ICf. 1/3 is ECF. of ecf, 75 - 80 % is interstir, 20 - 25% is plasma
what is the role of aquaporins
an integral membrane protein that lets water move across plasma membranes
how many aquaporins are in humans
ten types
how many types of aquaporins are in the proximal collecting tubule
five types
how many aquaprins in the red blood cell
2X10^5 copies per call, allowing for bidirectional movement of water
what is a solute vs an ion
ion is a charged solute (particle dissolved in water)
what is osmolality
the conc of solute in water
what kind of solution has higher osmolality?
a hypertonic solution
what regulates the movement of water
the osmostic pressure
what is osmotic pressure
the osmolality difference between two solutions
what is osmotic force
the movement of water across a semi perm membrane, in response to the osmotic gradient
what is the osmotic gradient
the difference is osmolarity in two compartments
explain why ecf has more water wrt osmotic gradients
the ecf has less solute, so is hypertonic, so more water can move out of it so that the osmolality of both sides (ecf and icf) can equalize
t/f: osmolality is the same in each fluid comp
yes! the overall concentration of any solute:water is the same
t/f: solute conc is the same in all fluid comp
NO the actual SOLUTES are different (ie the same solute isnt in each compartment)
where is na primarily found
outside of the cell, in the plasma and interstitium
where is k primarily found
mostly inside the cell
where is cl primarily found
mostly outside the cell, but conc still isnt as much as na
where is hco3 primarily found
mostly outside, but way less than na
where are large anions and proteins found
inside the cell. note that cell is at osmotic eq, but not chemical eq
what does the na - k pump maintain
maintains the difference in the solute concentrations
what does the na k atpase do
makes sure that intracell has high k, and extracell has high na.
pumps 3 na out, 2 k in, uses one atp
what is ouabin
an inhibitor of the nakatpase
what is digoxin
an inhibitor of nakatpase
why does water cross cell membranes
because solutes are restricted, so to create quillibrium in conc, water has to cross
where is anionic sodium restricted to
the ECF
what happens when you drink water (wrt ecf)
absorbed from gut into the ecf. ecf conc goes down. water then moves from ecf to icf. overall both ecf and icf vol increase
what is a hypotonic solution vs hypertonic solution
hypo is less conc. hyper is more conc. water will move to hypertonic sols to equalize
what happens when you eat salt (wrt ecf)
salt will stay in the ecf, causing its osmo to go up. so icf water has to leave to equalize, and cells shrink
what determines water movement between interstitial fliud and blood
the leaky exchange epithelium
what are starling forces
the forces that determine the movement of fliud between capillaries and interstit
what does hydrostatic pressure favour
pushes water from plasma into interstit
what does oncotic pressure favour
generated by albumin, keeps water inside blood vessels
where is albumin conc the highest
the plasma
what is fluid flux
permeability x (hydrostatic pressure grad- oncotic pressure grad)
how is hydrostatic pressure generated
generated by heart pumping
hydrostatic pressure wants fluid to move in which direction? oncotic pressure?
hstatic: out of caps. ocotic: into caps
where is movement regulated by gradients? by starling forces?
