1.3 : 呼吸の生理学 I: 呼吸器系の機能

The physiology of respiration involves three fundamental processes: ventilation, oxygenation, and the dynamics of compliance and resistance.

Ventilation is the process of inhaling and exhaling air.

Inhalation starts with the contraction of the diaphragm, external intercostal, and scalene muscles, which expands the chest cavity and reduces intrathoracic pressure, allowing air into the lungs.

Exhalation is driven by the elastic recoil of the lungs and chest wall, which raises intrathoracic pressure and expels air.

Oxygenation is the process by which atmospheric oxygen is supplied to the body's organs and tissues through diffusion across the alveolar-capillary membrane.

Oxygen moves from the alveoli to the arterial blood, while carbon dioxide moves from the arterial blood to the alveoli.

Next, compliance is the lung's ability to expand, influenced by the elasticity of lung tissues and the flexibility of the chest wall.

Lastly, resistance is the obstacle to airflow during breathing, mainly affected by the airway diameter. Bronchoconstriction increases airway resistance, while bronchodilation decreases it.