Week 3- Fluid Compartments and Solutes Flashcards
What are the main cations found in the body and are they extracellular or intracellular?
Na+ is extracellular
K+ is intracellular
What are the main anions found in the body and are they extracellular or intracellular?
Cl- is extracellular
Inorganic phosphate is intracellular
How the pH inside vs outside cells different?
Inside is slightly more acidic
How is the osmolarity in cells vs plasma different?
It’s identical apart from in the kidneys
Define diffusion
The spontaneous movement of solute molecules down their concentration gradient until they reach equilibrium
Define osmosis
The movement of water molecules down their conc gradient (across a selectively permeable membrane)
Define osmolarity
The concentration of solute in a solution
What are the limits of using osmolarity as an indicator to cell volume?
It is a bad indicator of cell volume as it doesn’t take into account cell permeability
What is tonicity?
A measure of cell volume that takes into account cell membrane permeability and solution composition
What is a hypertonic solution?
Osmolarity of solutes outside>inside so CELL SHRINKS
What is a hypotonic solution?
Osmolarity of solutes outside
What is an isotonic solution?
Osmolarity of solution outside=inside so cell stays the same
Why do transplant tissues need to be preserved?
Cells would die even after cooling due to disruption of ionic balance. This is because Na+/K+ ATPase doesn’t work under 15 degrees. This would mean Na+ flows in freely, causing water to flow in and causing cells to burst
How are transplant tissues transported?
By placing them in UW solution which has the properties:
No Cl- or Na+ ions present to prevent movement
Starch present
Extracellular impermeant solutes present
What are the 2 pressures that determine the flow of fluid in/out of blood vessels?
Colloid osmotic pressure and hydrostatic pressure
What is colloid osmotic pressure?
Concentration of plasma proteins is higher than outside, reducing water potential in the vessel and causing water to move into the vessel
What is hydrostatic pressure?
Pressure of blood flowing through the vessel which pushes fluid out
Which pressure out of colloid and hydrostatic usually dominates? What does this cause to happen?
Hydrostatic, so plasma leaks out of vessels
What are some routes by which substances exit blood vessels?
Lipid soluble go through membrane
Water soluble go through gaps
Proteins exit via vesicles
Plasma proteins can’t exit
How does oedema arise?
When lymphatic aren’t able to drain lymph at the rate it is draining out
What are the 2 types of oedema and how do they differ?
Inflammatory (due to leaky vessels)
Hydrostatic (hydrostatic pressure is too high eg high BP)
What is elephantiasis?
When parasitic worms block the lymphatics causing oedema
