Question

What causes air to flow out of the lungs during expiration

Answer 1

Expiration

Explanation:

Inspiration and expiration occur due to the expansion and contraction of the thoracic cavity, respectively

• Inspiration is the process that causes air to enter the lungs whereas expiration is the process that causes air to leave the lungs
• Expiration is typically a passive process that happens from the relaxation of the diaphragm muscle (that contracted during inspiration)
• Exhalation begins when inhalation ends
• Pleural cavity’s increased negative pressure leads to air uptake during inhalation, the pleural cavity will contract during the exhalation (due to relaxation of the diaphragm),which exerts pressure on the lungs and causes the pressure inside the cavity to be less negative
• An increase in pressure leads to a decrease in volume inside the lung, and air is pushed out into the airways as the lung returns to its smaller size
• The pleural cavity is so important to breathing because it’s pressure changes the volume of the lungs, and it provides a friction-less space for the lung to expand and contract against during breathing