Flashcards in 5. Fluid compartments Deck (41)
What percentage of the fluid in the body is intracellular?
What percentage of the fluid in the body is interstitial fluid?
What percentage of the fluid in the body is blood plasma?
What percentage of the fluid in the body is transcellular fluid?
Barriers in extracellular environments
Compartmentalise for different composition and function
e.g. Plasma membrane separates EC and IC fluids
How do layers of cells forming junctions with each other separate extracellular fluids?
Epithelial cell layers separate various interstitial spaces.
Endothelial cells line blood vessels, and are the main barrier separating the fluid of the blood (the plasma) and IC fluids.
What is the main cations of intracellular and extracellular fluids?
What is the main anions of intracellular and extracellular fluids?
Intracellular: Free organic phosphates
Name an important signalling cation found in intracellular and extracellular fluid
What are the concentrations, in mmol/l, of Na+, K+ Ca2+, Cl-, Organic Phosphates and proteins in extracellular fluid?
Na+: 150 mmol/l
K+: 5 mmol/l
Ca2+: 2 mmol/l
Cl-: 110 mmol/l
Organic phosphates: 5 mmol/l
Proteins: 1 mmol/l
What are the concentrations, in mmol/l, of Na+, K+ Ca2+, Cl-, Organic Phosphates and proteins in intracellular fluid?
Na+: 10 mmol/l
K+: 150 mmol/l
Ca2+: 10^-4 mmol/l
Cl-: 5 mmol/l
Organic phosphates: 130 mmol/l
Proteins: 2 mmol/l
What is the pH inside and outside cells?
a measure of the concentration of all solute particles in a solution
expressed as the total number of solute particles per litre.
Osmolarity in intracellular and extracellular fluid
(except in some parts of the kidney)
movement of water down its own concentration gradient, to an area of higher osmolarity
Can change cell volume
state of being permeable
What happens if membrane is permeable to water and solutes?
Both diffuse down concentration gradient
After equilibrium, there is no net volume change
What happens if membrane is impermeable to 1 or more solutes?
Net change in volume will occur as only water can move
If significant, cell may rupture
What feature does osmolarity not take into account and what is a more useful measure?
Tonicity is more useful
The strength of a solution as it affects final cell volume
What 2 elements does tonicity depend on?
Cell membrane permeability
Osmolarity of impermeant solutes out > in
Osmolarity of impermeant solutes out < in
Osmolarity of impermeant solutes out = in
Cell volume is unchanged
What feature do real cells have which prevents them from bursting due to having a higher osmolarity inside the cell than outside?
They have sodium-potassium pumps
Maintains a lower concentration of sodium inside than outside
Pump makes membrane effectively impermeable to Na+, as any Na+ that diffuses in is pumped out again (no net movement)
What does intracellular osmolarity of impermeant solutes (mainly high conc. proteins and low conc. Na +) balance?
Extracellular osmolarlity of impermeant solutes (mainly high conc. Na+).
What is the function of university of Wisconsin solution (UW)?
to reduce hypothermic cell swelling and enhance preservation for transplantation
What does UW solution provide?
No Na+ or Cl- (no influx possible)
Extracellular impermeant solutes (lactobionate ions, raffinose (a sugar))
Macromolecular colloid (starch)
Together, these factors reduce cell swelling in cooled tissues.
Why are rapid cooling and tissue preservation solutions required for transplant organs?
Sodium pumps stop working <15 degrees
Na+ and Cl- enter cells with water and K+
Cells swell and bleb which can cause cell death