Final answer:
The diaphragm is a large, dome-shaped muscle below the lungs that allows breathing to occur when it alternately contracts and relaxes. It separates the thoracic and abdominal cavities and plays a crucial role in respiration.
Step-by-step explanation:
The diaphragm is a large, dome-shaped muscle below the lungs that allows breathing to occur when it alternately contracts and relaxes. It separates the thoracic and abdominal cavities and plays a crucial role in respiration.
During inhalation, the diaphragm contracts and moves downward, causing the chest to expand and creating a vacuum that allows air to flow into the lungs. During exhalation, the diaphragm relaxes and moves upward, reducing the volume of the chest and forcing air out of the lungs.
The diaphragm's contraction and relaxation are controlled by the phrenic nerve, and any disruptions in its function can lead to breathing difficulties or respiratory disorders.