Upon contraction, the diaphragm does what?

Upon contraction, the diaphragm does what?

• A. Lifts the Ribs
• B. Expands the Abdomen
• C. Increases Thoracic Pressure
• D. Pulls Down on the Central Tendon

Answer: (D)

During contraction, the diaphragm shortens and pulls on its central tendon, moving it downward. This downward pull flattens the diaphragmatic dome and increases the vertical dimension of the thoracic cavity, expanding thoracic volume and lowering intrathoracic pressure to draw air into the lungs. It does not lift the ribs (that’s mainly done by the intercostals) and it doesn’t increase thoracic pressure. The downward pull on the central tendon is the essential action that enables inspiration.

During contraction, the diaphragm shortens and pulls on its central tendon, moving it downward. This downward pull flattens the diaphragmatic dome and increases the vertical dimension of the thoracic cavity, expanding thoracic volume and lowering intrathoracic pressure to draw air into the lungs. It does not lift the ribs (that’s mainly done by the intercostals) and it doesn’t increase thoracic pressure. The downward pull on the central tendon is the essential action that enables inspiration.