What structures comprise the respiratory pump?

What structures comprise the respiratory pump?

• A. diaphragm, external intercostals, scapulae
• B. scalenes, sternocleidomastoid
• C. proximal, distal
• D. sternum, ribs, vertebrae

Answer: (D)

The respiratory pump relies on the rib cage to create pressure changes in the chest that help push venous blood back to the heart during breathing. The structures that comprise this pump are the sternum, ribs, and vertebrae—the bones that form the thoracic cage and move to expand and contract the chest with respiration. When you inhale, the diaphragm and rib cage expand, lowering intrathoracic pressure and aiding venous return; when you exhale, the cage recoils and pressure rises. The scapulae are not part of the rib cage, and the neck muscles listed act as accessories in breathing rather than forming the pump’s structural framework. Therefore, the sternum, ribs, and vertebrae best fit the concept.

The respiratory pump relies on the rib cage to create pressure changes in the chest that help push venous blood back to the heart during breathing. The structures that comprise this pump are the sternum, ribs, and vertebrae—the bones that form the thoracic cage and move to expand and contract the chest with respiration. When you inhale, the diaphragm and rib cage expand, lowering intrathoracic pressure and aiding venous return; when you exhale, the cage recoils and pressure rises. The scapulae are not part of the rib cage, and the neck muscles listed act as accessories in breathing rather than forming the pump’s structural framework. Therefore, the sternum, ribs, and vertebrae best fit the concept.