During exercise, the depth of respiration increases. Name the muscles involved in increasing the depth of respiration and explain how muscle contraction causes this increase.

Muscles of respiration: The muscles of respiration are those muscles that plays role in inhalation and exhalation, by aiding in the expansion and contraction of the thoracic cavity. The diaphragm and intercostal muscles drive respiration during quiet breathing.

During an increment in exercise, minute ventilation increases same to metabolic rate, an increase in lung volume inspiration and tidal volume.

Mechanism

Contraction of diaphragm generates tension within its fibers, displacing the central tendon caudally. Consequently:

A) pleural pressure falls, allowing air to flow into the airways and alveoli, thereby increasing lung volume;

B) abdominal pressure increases, thus pushing the abdominal cavity downward, allowing the thorax to expand;

C) the ribcage is lifted upwards and outwards by action of the scalenes and sternocleidomastoid on the sternum, and external intercostal muscles on the ribs.