MANUAL PHYSIOLOGY PRACTICAL - Repository:The Medical ...

FM/UOJ
Experiment 2
OSMOTIC FRAGILITY AND PERMEABILITY PROPERTIES
OF RED BLOOD CELLS
When cells placed in hypotonic solutions water enters the cell due to osmosis and
causes the cells to swell. When cells are distended beyond a limit, the cell membrane is
stretched and the contents of the cell leak out. This effect can be easily detected when red
cells are studied because haemoglobin leaks out and forms a clear pink solution
(haemolysis).
Demonstration
Observe the steps in drawing blood form a volunteer (venipuncture). Note the
chemical used to prevent blood clotting (anticoagulant) and the care taken in mixing the
anticoagulant with blood to prevent mechanical haemolysis.
Anticoagulant used:…………………………………………
The following solutions are prepared:
a) sodium chloride: serial dilution from 0 to 0.9%,
b) glucose: serial dilution from 0 to 5%,
c) urea: serial dilution from 0 to 2% and
d) 0.9% NaCl with Soap solution (1 ml).
These solutions [10 ml] are taken in two sets of test tubes and placed in racks.
Two drops of blood are added to each test tube. One set is kept as it is for
observation and the other set centrifuged and kept.
Precautions:
………………………………………………………………………………………………
………………………………………………………………………………………………
………………………………………………………………………………………………
………………………………………………………………………………………………
………………………………………………………………………………………………
Exercise
1. Record the concentration of each solution where haemolysis begins and the
concentration where haemolysis is complete.
Sodium Chloride beginning………….. Complete……………………..
Glucose beginning………….. Complete……………………..
Urea beginning………….. Complete……………………..
Observation in Soap solution……………………………………………..
Introductory
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