Body Fluids Flashcards
Ions make up …% of solutes
95%
Formula to calculate osmotic pressure
P = r × C × R × T
- P: Osmotic pressure*
- r: reflection coefficient*
- C: Conc. of dissolved substance*
- R: General gas constant*
- T: Temperature*
Describe the Reflection coefficient
- If a substance cannot diffuse accross the membrane
- Coefficient value = 1
- If a substance can pass freely
- Coefficient value = 0
Describe Molarity
mol/liter
- Anelectrolites:
- 1 mol dissolved substance in 1 litre
- Has an osmotic pressure of 2.27 MPa
- Molarity of body fluids:
- Unit: mmol/l
- Osmotic pressure measured in kPa
Osmolarity
1 osmol/l = 6×1023 dissolved substance / liter
Molality
mol/kg
- No. mol of substance in 1kg solvent
- Correlated with freezing point depression
Calculate molality
- Electrolites:
- Conc. x dissociation constant
- (1 mol NaCl - 3.72°C)
- Anelectrolites:
- Conc. related to freezing point
Define Osmolality
Measures of the body’s electrolyte-water balance
Freezing point depression for water
1.86 °C
Freezing point depression for blood plasma
0.56°C
Calculate osmolality:
- For dilute anelectrolite solutions
mosmol/kg = mmol/kg
Calculate osmolality:
- For complete dissociation
moslmol/kg = mmol/kg x no. dissociated ions
(E.g NaCl has 2 dissociated ions, Na+ + Cl-)
Calculate osmolality:
- For concentrated solutions
- (Biological fluids)
mosmol/kg = mmol/kg x g
- g: osmotic coefficient*
- Plasma NaCl - g=0.926*
Oncotic/colloidosmotic pressure
Pressure maintained by proteins and colloid particles
Give the anelectrolite concentrations of the blood plasma
- Glucose:
- 5 mmol/l (Monogastric)
- 3 mmol/l (Ruminants)
- 10 mmol/l (Birds)
- Urea: 3-10 mmol/l
- NPN 15-25mmol/l
NPN = ‘Non-protein nitrogen’
Give the concentrations of the cations in blood plasma
- Na+ = 140 mmol/l
- K+ = 4 mmol/l
- Mg2+ = 1.5 mmol/l
- Ca2+ = 1.25 mmol/l
Give the concentrations of the anions in blood plasma
- Cl- = 110 mmol/l
- HCO3- = 27 mmol/l
- Protein = 17 mmol/l
- Phosphate = 2 mmol/l
- Sulphate = 1 mmol/l
- Organic acids = 4 mmol/l
Value of osmolality of blood plasma calculated based on total electrolyte concentration
280 mmol/kg
Value of osmolality of blood plasma calculated by freezing point depression
300 mmol/kg
Calculate non-ionic osmolality
300 mmol/kg - 280 mmol/kg
(Freezing point osmolality - total electrolyte osmolality)
= 20 mmol/kg
Give the concentration of plasma proteins
60-80 g/l
Give the oncotic pressure (Osmotic pressure of plasma proteins)
2.7-3.4 kPa
Give the molarity of plasma proteins
1.2-1.5 mmol/l
How are plasma proteins quanitfied?
Kjeldahl method
- Formula to calculate protein concentration
- Approximate value
Oncotic pressure / Osmotic pressure of 1 mol/l
Approximately 2.5 mmol/l
![](https://s3.amazonaws.com/brainscape-prod/system/cm/254/164/486/q_image_thumb.png?1537712057)
100 µmol/l
![](https://s3.amazonaws.com/brainscape-prod/system/cm/254/164/765/q_image_thumb.png?1537712103)
50 (50-200) µmol/l
![](https://s3.amazonaws.com/brainscape-prod/system/cm/254/164/778/q_image_thumb.png?1537712135)
< 60-200 µmol/l
![](https://s3.amazonaws.com/brainscape-prod/system/cm/254/164/898/q_image_thumb.png?1537712230)
25%
![](https://s3.amazonaws.com/brainscape-prod/system/cm/254/164/943/q_image_thumb.png?1537712247)
50%
![](https://s3.amazonaws.com/brainscape-prod/system/cm/254/164/946/q_image_thumb.png?1537712262)
25%
![](https://s3.amazonaws.com/brainscape-prod/system/cm/254/164/959/q_image_thumb.png?1537712280)
3-10 mmol/l
![](https://s3.amazonaws.com/brainscape-prod/system/cm/254/164/967/q_image_thumb.png?1537712302)
~ 5 mmol/l
Give the methods of fractionation
- Paperelectrophoresis
- Geleelectrophoresis
- Immunoelectrophoresis
- HPLC
- Ultracentrifuging
- Gel-filtration
- Affinity chromatography
Paperelectrophoresis
- Only fibrinogen and albumin can be seperated
- Other proteins can be found in globulin fraction
- a mixture of hundreds of different proteins
- Can be used to identify over 300 different proteins
Gelelectrophoresis
![](https://s3.amazonaws.com/brainscape-prod/system/cm/254/340/055/a_image_thumb.png?1537861446)
Ultracentrifuging
- High G developed in an ultracentrifuge vacuum
- Macromolecules separated according to sedimentation constants
Ion exchange chromatography
Seperates proteins on the basis of their charge
Gel-filtration
- Seperation with polysaccharide beads (dextran)
- Protein with small molecular weight can infiltrate the beads
- Proteins therefore spends more time in the beads
- Bigger molecules are washed away faster than the smaller ones
Affinity chromatography
- Beads covalently bind a specific antibody
- Antibody is produced against the protein to the bead
- Proteins will be selected from a mixture by the antibodies
- The rest of the proteins will be washed away
Immune electrophoresis
- Antibody distributed in a gel
- Gel poured on a sheet of glass
- Electric field applied
- Precipitation arcs with the antigen left behind
HPLC
High Pressure Liquid Chromatography
- High pressure perfusion
- Divides proteins in a solid phase column
![](https://s3.amazonaws.com/brainscape-prod/system/cm/254/340/416/q_image_thumb.png?1537863404)
- 60-70 kDa
- 55%
- 45 g/l