Breathing In Apr 2026

: The external intercostal muscles contract, pulling the rib cage upward and outward.

: Tiny air sacs where gas exchange occurs with capillaries. Structure and function of the gas exchange system - BBC breathing in

"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 : The external intercostal muscles contract, pulling the

: Air is "sucked in" through the nose or mouth to equalize this pressure, traveling down the trachea and into the alveoli. This process is driven by muscular contraction that

: The diaphragm (a dome-shaped muscle) contracts and moves downward.

🫁 : The primary "product" of this phase is the delivery of fresh oxygen ( O2cap O sub 2

: As volume increases, the air pressure inside the lungs decreases below atmospheric pressure.