For inspiration of air,which of the following happens first?
A) diaphragm descends and rib cage rises
B) intrapulmonary pressure drops
C) air (gases) flows into lungs
D) thoracic cavity volume decreases

Question

Quizplus · Accepted Answer

When we inhale, the first thing that happens is that the diaphragm muscles contract and move downward, causing the size of the thoracic cavity to increase. This action causes the rib cage to expand, and the intercostal muscles between the ribs contract to further enlarge the thoracic cavity. This expansion of the thoracic cavity results in a decreased intrathoracic pressure relative to the atmospheric pressure, therefore allowing air to flow into the lungs. Finally, intrapulmonary pressure drops, and air (gases) flows into the lungs.

For Inspiration of Air,which of the Following Happens First