: These muscular actions expand the thoracic cavity, increasing the volume of the lungs.
: The external intercostal muscles contract, pulling the rib cage upward and outward.
: The diaphragm (a dome-shaped muscle) contracts and moves downward. breathing in
: As volume increases, the air pressure inside the lungs decreases below atmospheric pressure.
"Breathing in," or , is the active phase of the respiratory cycle where air is drawn into the lungs. This process is driven by muscular contraction that creates a pressure gradient between the atmosphere and the chest cavity. Key Features of Inhalation : These muscular actions expand the thoracic cavity,
: Air is "sucked in" through the nose or mouth to equalize this pressure, traveling down the trachea and into the alveoli.
) to the alveoli, where it diffuses into the bloodstream to be used for cellular energy production. Structural Pathway Air follows a specific order during inhalation: : Entry point where air is warmed and filtered. Trachea : The main windpipe. Bronchi : Two main tubes leading to each lung. Bronchioles : Smaller branching air passages. : As volume increases, the air pressure inside
🫁 : The primary "product" of this phase is the delivery of fresh oxygen ( O2cap O sub 2