During inhalation, the diaphragm does what?

During inhalation, the diaphragm does what?

• A. Stays the same
• B. Contracts and moves downward (flattens)
• C. Relaxes and moves upward
• D. Contracts and moves upward

Answer: (B)

During inhalation, the diaphragm contracts. As it contracts, it pulls downward and flattens from its dome shape, increasing the vertical size of the thoracic cavity and expanding the lungs. This expansion lowers the pressure inside the chest, drawing air into the lungs. The rib cage also rises a bit as the intercostal muscles help widen the chest, aiding the inhalation process. After inhalation, the diaphragm relaxes and moves back upward, reducing thoracic volume and helping push air out during exhalation. If the diaphragm stayed the same, air wouldn’t be drawn in; if it relaxed and moved upward, that would occur during exhalation; contracting and moving upward would reduce chest volume and oppose inhalation.

During inhalation, the diaphragm contracts. As it contracts, it pulls downward and flattens from its dome shape, increasing the vertical size of the thoracic cavity and expanding the lungs. This expansion lowers the pressure inside the chest, drawing air into the lungs. The rib cage also rises a bit as the intercostal muscles help widen the chest, aiding the inhalation process. After inhalation, the diaphragm relaxes and moves back upward, reducing thoracic volume and helping push air out during exhalation. If the diaphragm stayed the same, air wouldn’t be drawn in; if it relaxed and moved upward, that would occur during exhalation; contracting and moving upward would reduce chest volume and oppose inhalation.