Question

One of the following depend more on ribs and their muscles for breathing than diaphragm.

• A. Female (human)
• B. Monkey
• C. Kangaroo
• D. All of the above

Answer 1

The correct option is D All of the above

The ribs and the various muscles of respiration aid in both inspiration and expiration, which require changes in the pressure within the thoracic cavity. The important respiratory muscles are the diaphragm, the external intercostal and the internal intercostal muscles. The ribs and the respiratory muscles work to achieve this by changing the dimensions of the thoracic cavity.
When a person inhales, the rib cage move out and up in order to accommodate the incoming air. On the other hand, when a person exhales, the rib cage move in, in order to expel the carbon dioxide. Both the external intercostal muscles and the internal intercostal muscles elevate the ribs, thus increasing the width of the thoracic cavity, while the diaphragm contracts to increase the vertical dimensions of the thoracic cavity, and also aids in the elevation of the lower ribs. The muscles that connect the ribs together ensure that the diaphragm can expand and contract appropriately as air is breathed in and expelled. Thus, in mammals, breathing depends more on ribs and their muscles for breathing than diaphragm.