Discuss the important factors in exchange of gases and substrates between capillaries and tissue cells.

## College Answer

Good answers were based around Fick’s Law, Starling forces and the Gibb’s

Donnan effect.

It was expected that candidates would give Fick’s equation and describe the

components :

Fick’s Law J = -DA dc/dx

Candidates were also expected to describe Starlings equation and the equation for

Osmotic Pressure. Starling Equation:

Fluid movement = k[(Pc-Pi) – s(πp – πi)]

Osmotic pressure : sRT(Ci-Co).

Gibb’s Donnan effect and, other mechanisms of transport (filtration and pinocytosis)

was also expected for a good answer.

Syllabus: A combination C1c2.d, C21 2.e, C2b2.c, C2b2.e

References: Pharmacology and Physiology in Anesthetic Practice, Stoelting pgs

294-300, 322- 325