Capillary exchange and tissue fluid sim
Pump up the pressure and set the flow on a working capillary model, then watch fluid, oxygen and glucose leave one real capillary and carbon dioxide enter, take your own readings and graph them.
Transport in humans · covers the O-Level, IGCSE, GCSE topic
What the sim shows
Model: blood pressure falls from 35 to 15 mmHg along a capillary at rest; where it is above the plasma proteins' pull (24.5 mmHg) fluid leaves, below it fluid returns: 14 mL/min out, 11.5 back, 2.5 left for lymph. Blood spends 1.5 s in a 0.5 mm capillary. Values illustrative, from memory; the pressure balance is beyond the syllabus.
- Visking tubing: the model capillary's partly permeable wall
- Model blood: red paint grains in starch and glucose solution
Use it in your lessons
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