fluid compartments Flashcards
Osmole:
the number ofmolesof solute that contribute to the osmotic pressure of a solution
e.g. number of molecules so
nacl is *2
cacl3 *3
glucose *1
tonicity what is
strength” of a solution as it affects the final cell volume.
what is tonicity dependenet on
cell membrane permeability and the solution composition.
whats hypertonic
he osmolarity of the impermeant solutes outside the cell are greater than those inside the cell. The cell therefore shrinks in the solution.
what is Hypotonic solutions
the osmolarity of the impermeant solutes outside the cell are less than those inside the cell. The cell therefore swells in the solution.
what is isotonic
the osmolarity of the impermeant solutes outside the cell is identical to those inside the cell. The cell volume therefore remains the same.
describe the fluid composition of the fluid
The cell membrane is permeable to H2O, and as we have seen, the concentration of impermeant solutes (proteins) is much higher inside the cell than in the interstitial fluid or plasma.
why doesn’t it burst
The cells don’t burst because the Na+K+-ATPase maintains the concentration of Na+ ions (cyan squares) much lower inside the cell than outside.
The ATPase makes the membrane “effectively impermeable” to Na+ because any Na+ that diffuses in down the Na+ concentration gradient is actively pumped out again. Thus there is no net movement of Na+ across the membrane.
how to slow down isceamic changes
rapid cooling of the tissue/organ to +4°C.
why can the cells die
Na+K+-ATPase stops functioning below 15°C
there is little O2 and therefore little ATP to fuel the pump
Unless precautions are taken, Na+ will enter the cell (along with Cl-) and water will also enter as K+ exits. Cells are likely to swell and their membranes bleb, resulting in cell death.
name a precaution
perfuse the organ with a solution known as University of Wisconsin solution (UW). This is formulated to reduce hypothermic cell swelling and enhance preservation.
name the main factors
Lack of Na+ or Cl- (therefore no influx possible).
Presence of extracellular impermeant solutes (lactobionate ions, raffinose).
Presence of a macromolecular colloid (starch)
purpose of Allopurinol and glutathione
acts as an antioxidants, helping to protect the organs from damage from reactive oxygen species (ROS).
what is the layer that lines all blood vessels
endothelial cells which have pores.
how is the colloid osmotic pressure (COP) created
higher concentrations of plasma proteins inside the capillary than outside
