Gas Exchange in Middle Ear through the Mucosa

Abstract

Ventilation of the middle ear is of two types: 1) ventilation via the eustachian tube and 2) ventilation via the middle ear mucosa. Ventilation via the middle ear mucosa is performed by gas exchange between the middle ear and the blood. The gas composition of the middle ear differs from that of air and resembles that of venous blood. The gas composition and the pressure of the middle ear may be affected by the gas composition of blood and the condition of the middle ear mucosa. When there is a difference in partial pressure between the middle ear and the blood, gas diffuses through the mucosa to equalize the partial pressures. Gas exchange in the middle ear through the mucosa is due to diffusion which depends on the difference in partial pressure. It is not known whether gas exchange between the middle ear and the blood occurs only by gas diffusion between the middle ear and blood and depends on differences of partial pressure.