The table below compares the pressures of a capillary with the surrounding tissue fluid:
| Property | Capillary | Tissue fluid |
|---|---|---|
| Hydrostatic pressure | 4.8 kPa | 0.20 kPa |
| Oncotic pressure | 3.8 kPa | 0.05 kPa |
The net movement of fluid between the capillary and tissue fluid depends on the net driving force (JvJ_vJv):
Jv=(Pc−Pi)−σ(πc−πi) J_v = (P_c - P_i) - \sigma(\pi_c - \pi_i) Jv=(Pc−Pi)−σ(πc−πi)Where:
In a particular tissue, the reflectance factor (σ\sigmaσ) was found to be 0.80. Use this information and the data in the table to calculate a value for the net driving force, JvJ_vJv, and predict the direction of fluid movement.
Suggest the effect of a liver disease that reduces the synthesis of plasma proteins on the net driving force (JvJ_vJv) and explain how this affects the volume of tissue fluid formed.
15 exam-style questions on OCR A A Level Biology Transport in animals. Each one has a worked solution and a mark scheme showing where the marks go.