MICROANATOMY

Detailed explanation-1: -Pulmonary ventilation is commonly referred to as breathing. It is the process of air flowing into the lungs during inspiration (inhalation) and out of the lungs during expiration (exhalation).

Detailed explanation-2: -When the lungs inhale, the diaphragm contracts and pulls downward. At the same time, the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside. As a result, air rushes in and fills the lungs.

Detailed explanation-3: -During hyperpnea, also known as forced breathing, inspiration and expiration both occur due to muscle contractions.

Detailed explanation-4: -Inspiration occurs when the diaphragm and the external intercostal muscles contract. Expiration occurs when the diaphragm and the intercostal muscles relax. The contraction or relaxation of muscles around the lungs changes the entire volume of air inside the lungs, and so does the pressure.