Mechanics of Ventilation

Ventilation in the physiological sense (strictly, pulmonary ventilation) refers to the volume of air breathed in and out of the lungs: typically 5-6 litres per minute for an average-sized person at rest, with the possibility of increasing by up to twenty-fold in exercise.

During Inspiration, the diaphragm contracts and flattens in order to expand the thoracic cage and increased the cavity of the thorax. Pressure in the thorax decreases to a level below atmospheric pressure. This time air moves into the lungs.

After a complete inspiration, the diaphragm relaxes, and the lungs recoil to its normal position, the size of thoraxic cavity decreases, increasing pressure to levels greater than atmopheric pressure. Air then flows out of the lungs into the atmosphere.

Mechanics of Breathing Part 1

Mechanics of Breathing Part 1