Fluid Compartments Flashcards
What is the most plentiful cation in the plasma?
Sodium
What is the most plentiful cation inside the cell?
Potassium (This is due to Na+/ K+ATPase pumps pumping 2 x K+into the cell for every 3 x Na+ which are pumped out the cel
Is Cl- found in a higher concentration inside the cell or out?
Found in much higher concentration outside the cel
What is the main intracellular anion?
Organic Phosphate
What does phosphorylation of proteins do?
Key for the activation and inactivation of certain proteins
What is the difference in the osmolarity between the blood and the intracellular compartment?
They are identical, so there is not much of an osmotic effect
What is the concentrations of Na+ inside the cell and outside the cell?
Outside = 150mmol/L
Inside = 10mmol/L
What is the concentrations of K+ inside the cell and outside the cell?
Inside = 150mmol/L
Outside = 5mmol/L
What is the concentration of Cl- inside and outside the cell?
Inside = 5mmol/L
Outside = 110mmol/L
What is the definition of diffusion?
Diffusion is the spontaneous movement of a solute down a concentration gradient until the solute molecules reach an equilibrium
Is the inside of the cell more acidic or more alkaline than the plasma?
Inside of the cell is more acidic- although the difference in pH is small, since the concentration of H+ ions determines pH and this follows a logarithmic scale, an small increase indicates a 2 fold increase in the concentration of H+ ions
What is meant by osmolarity?
A measure of the concentration of all the solute particles in a solution
What is an osmole?
The number of moles of solute which contribute to the osmotic pressure of a solution
What is the osmolarity of a solution which has a 150 mmol Conc of NaCl, 1 mmol/L conc of CaCl2 and 2mmol/L conc of glucose?
150 x 2 ions in NaCL = 300
1 x 3 ions in CaCl2 = 3
2 x 1 compound in glucose = 2
Total = 305
What is meant by tonicity?
The strength of a solution as it affects the final cell volumes - depends on both cell membrane permeability and solution composition
What happens to cells when they are placed in hypertonic solutions?
The cell shrinks
What is meant by a hypertonic solution?
A hypertonic solution is one where the solute osmolarity outside the cell is much greater than those of inside the cell. therefore, there is a low water concentration outside the cell, and hence water will move from outside the cell into the solution, resulting in a shrinkage of the cell
What happens when a cel is placed inside a hypotonic solution?
The cell swells
What is a hypotonic solution?
A solution in which the solute osmolarity is low in the solution. Therefore the concentration of water is higher outside the cell than inside, and so water moves from the outside solution into the cel, resulting in the swelling of the cell
What is an isotonic solution?
Where the osmolarity of the impermeant solutes outside the cel is the same as those inside the cell
WHat happens to the cell volume when placed in an isotonic solution?
Nothing - stays the same size
Why do cells of the body not 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.
What substances can diffuse across the lipid bilayer?
Gases like oxygen and carbondioxide and other hydrophobic molecules like steroids
Why are transplanted organs cooled when transported to their recipient?
When any tissue loses its blood supply, ischaemic changes occur, but these can be significantly slowed by rapid cooling of the tissue/organ to +4°C.
