Lungs do not inhale by themselves; they simply follow the chest, as the diaphragm contracts and flattens downward, pressure inside the thorax falls and air is pulled in. As the rate runs from 6 to 40 breaths a minute, each tidal volume stretches or shrinks with it. Pneumothorax collapses that lung; emphysema makes exhaling the hard part, because broken alveolar walls steadily destroy a gas-exchange surface of roughly 70 m².
Lungs do not inhale by themselves; they simply follow the chest, as the diaphragm contracts and flattens downward, pressure inside the thorax falls and air is pulled in. As the rate runs from 6 to 40 breaths a minute, each tidal volume stretches or shrinks with it. Pneumothorax collapses that lung; emphysema makes exhaling the hard part, because broken alveolar walls steadily destroy a gas-exchange surface of roughly 70 m².
Related topics in Human Body