Glottis

Sinuses

Meatus

Nostril

Conchae

Minute ventilation (V̇E) can be increased by decreasing tidal volume.

About 1/3 of inhaled air reaches the conductive zone where it takes part in gas exchange.

About 1/3 of inhaled air reaches the respiratory zone where it takes part in gas exchange.

All inhaled air reaches the respiratory zone where it takes part in gas exchange.

Minute ventilation (V̇E) can be increased by increasing the respiratory rate.

Lung compliance increases in lungs where some alveoli have collapsed.

The elastic recoil of the lung is opposite to the elastic recoil of the chest wall.

Pulmonary surfactant lowers surface tension and decreases lung compliance.

The human lung is very compliant at higher transpulmonary pressures.

The elastic recoil of the lung increases as lung compliance increases.

The intra-alveolar pressure becomes negative relative to the atmospheric pressure.

The intrapleural pressure becomes positive relative to the atmospheric pressure.

The intrapleural pressure stays unchanged.

The intra-alveolar pressure stays unchanged.

The intra-alveolar pressure becomes positive relative to the atmospheric pressure.

The diaphragm is active in both inspiration and expiration.

The most important expiratory muscle is the diaphragm.

Contraction of the external intercostal muscles causes the ribs to move upward and outwards.

Contraction of the diaphragm reduces the volume of the thoracic cavity.

Expiration muscles are always active during expiration.