ANATOMY

Detailed explanation-1: -When you breathe in, or inhale, your diaphragm contracts and moves downward. This increases the space in your chest cavity, and your lungs expand into it. 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.

Detailed explanation-2: -As the diaphragm contracts (moves downward), the volume of the thoracic cavity increases and the intra-alveolar pressure decreases from an atmospheric pressure of 760mmHg to   756mmHg. A pressure gradient is established and air enters the lungs. The external intercostal muscles also assist inspiration.

Detailed explanation-3: -When you breathe out (exhalation), the diaphragm moves up and the chest wall muscles relax, causing the chest cavity to get smaller and push air out of the respiratory system through the nose or mouth.

Detailed explanation-4: -When you breathe in, your diaphragm contracts (tightens) and flattens, moving down towards your abdomen. This movement creates a vacuum in your chest, allowing your chest to expand (get bigger) and pull in air. When you breathe out, your diaphragm relaxes and curves back up as your lungs push the air out.

Detailed explanation-5: -During inspiration, the diaphragm and external intercostal muscles contract, causing the rib cage to expand and move outward, and expanding the thoracic cavity and lung volume. This creates a lower pressure within the lung than that of the atmosphere, causing air to be drawn into the lungs.