What is the dome-shaped muscle that separates the thoracic cavity from the abdominal cavity and aids breathing?

What is the dome-shaped muscle that separates the thoracic cavity from the abdominal cavity and aids breathing?

• A. Larynx
• B. Aorta
• C. Diaphragm
• D. Trachea

Answer: (C)

The diaphragm is the major muscle used for breathing and sits as a dome between the thoracic and abdominal cavities. When it contracts, it moves downward and flattens, increasing the volume of the thoracic cavity. This expansion lowers the air pressure inside the lungs, causing air to flow in. When it relaxes, it returns to its curved shape, reducing thoracic volume and helping to push air out. The other items aren’t muscles that separate the chest from the abdomen or drive respiration: the larynx is the voice box, the aorta is a major blood vessel, and the trachea is the airway that conducts air but isn’t a muscle.

The diaphragm is the major muscle used for breathing and sits as a dome between the thoracic and abdominal cavities. When it contracts, it moves downward and flattens, increasing the volume of the thoracic cavity. This expansion lowers the air pressure inside the lungs, causing air to flow in. When it relaxes, it returns to its curved shape, reducing thoracic volume and helping to push air out. The other items aren’t muscles that separate the chest from the abdomen or drive respiration: the larynx is the voice box, the aorta is a major blood vessel, and the trachea is the airway that conducts air but isn’t a muscle.