AP BIOLOGY

Detailed explanation-1: -The pleural cavity always maintains a negative pressure. During inspiration, its volume expands, and the intrapleural pressure drops. This pressure drop decreases the intrapulmonary pressure as well, expanding the lungs and pulling more air into them. During expiration, this process reverses.

Detailed explanation-2: -Breathing in The muscles between your ribs also help enlarge the chest cavity. They contract to pull your rib cage both upward and outward when you inhale. As your lungs expand, air is sucked in through your nose or mouth. The air travels down your trachea, or windpipe, and into your lungs.

Detailed explanation-3: -During inspiration, the diaphragm contracts and the thoracic cavity increases in volume. This decreases the intraalveolar pressure so that air flows into the lungs.

Detailed explanation-4: -During inspiration, the diaphragm and the inspiratory intercostal muscles actively contract, leading to the expansion of the thorax. The intrapleural pressure (which is usually-4 mmHg at rest) becomes more subatmospheric or more negative.

Detailed explanation-5: -When you exhale, muscles decrease the size of your chest cavity and squeeze your lungs. This decreases their volume, so pressure inside the lungs increases.