MICROANATOMY

Detailed explanation-1: -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.

Detailed explanation-2: -Let’s find out. During exhalation, the intercostal muscles and diaphragm relax, causing the chest cavity to become smaller and the volume of the lungs to decrease. As volume and pressure have an inverse relationship, this will cause pressure in the lungs to increase.

Detailed explanation-3: -Decreased lung dimensions lead to the alveolar pressure surpassing the atmospheric pressure, as explained by the Boyle law. As a result, air flows from the alveoli to the atmosphere until reaching a new equilibrium between the two pressures.

Detailed explanation-4: -Contraction of the inspiratory muscles expands the chest wall, lowering the pressures in the thoracic cavity (both intrapleural and alveolar pressures decrease)-consider Boyle’s law*.

Detailed explanation-5: -During inhalation, the volume of the lungs increases and the pressure inside the lungs decreases below that of atmospheric pressure. This creates a pressure gradient that draws air into the lungs.