fluids solutes and compartments Flashcards
- What is the most plentiful cation in the plasma?
- What is the most plentiful anion in the plasma?
Na+
Cl-
what is the most plentiful cation in the cell and what is it neutralised by?
what is the most plentiful anion in the cell?
K+, proteins, nucleic acids and phosphorylated proteins
phosphate ion
what are the roles of phosphate ion?
cell signalling
phosphorylate proteins to activate or deactivate them
ATP production
- What does the concentration of protons affect?
- How do you know there are not normally significant osmotic effect in blood and intracellular compartment?
ph
Osmolarity between the two is identical
- What is diffusion?
- What is osmosis?
The spontaneous movement of solute down a concentration gradient until the solute molecules reach an equilibrium
Movement of water down its own concentration gradient Moves water to an area of higher osmolarity
- What is meant by osmolarity?
- What is an osmole?
Measure of concentration of all the solute particles in the solution
The number of moles of solute that contribute to the osmotic pressure of a solution
- Define tonicity
- What 2 things does tonicity depend on?
The strength of a solution as it affects the final cell volume
Cell membrane permeability Solution composition
- What is a hypertonic solution?
- What is a hypotonic solution?
- What is an isotonic solution?
Osmolarity of impermeant solutes outside the cell are greater than those inside the cell ,So the cell shrinks
Osmolarity of the impermeant solutes outside the cell are less than those inside the cell , so cell swells Osmolarity of impermeant solutes outside cell = inside cell So cell volume is unchanged
- Why don’t cells burst if the cell membrane is permeable to H2O molecules?
- How does ATPase make the membrane effectively impermeable to Na+?
Because the Na+/K+-ATPase maintains the concentration of Na+ ions to be much lower inside the cell than outside, so water doesn’t go into the cell and damage it
As any Na+ that diffuses in down the Na+ concentration gradient is actively pumped out again, there is no net movement of Na+ across the membrane into the cell
- What 2 methods can molecules impermeable to phospholipid membrane use for transportation across a biological membrane through transport proteins?
- Below what temperature does the Na+K+-ATPase stop functioning?
- Active transport using energy from ATP hydrolysis against an electrochemical gradient
- Passive, facilitating flow of molecules down an electrochemical gradient (facilitated diffusion)
15 degrees Celsius
- What does the University of Wisconsin solution do?
Perfusion solution- Reduces hypothermic cell swelling and enhances preservation of donated organs
- List the 3 main factors that serve to reduce swelling in UW-infused tissues
Lack of Na+ or Cl- so no influx occurs
Presence of extracellular impermeant solutes eg lactobionate ions, raffiinose Presence of macromolecular colloid- eg starch
- What does allopurinol and glutathione act as?
Antioxidants - helping to protect the organs from damage from reactive oxygen species (ROS)
- How do plasma proteins leave the blood vessels?
- How can small, water soluble substances leave the blood vessels?
- How do lipid-soluble substances leave the blood vessels?
They generally cannot cross endothelial cell membranes and cannot get through the pores between cells
They pass through the pores between cells They pass through the endothelial wall
- What is solute and fluid movement across a vessel wall determined by?
Opposing hydrostatic pressure of blood flowing through the vessels (pushing outwards)
and osmotic pressure (Colloid Osmotic Pressure) outside of blood vessel (pulling inwards)
