Question

When you pulled the diaphragm down what change occurred in chest cavity pressure (think about what changes in pressure occur during inspiration)? Explain how this change in chest cavity pressure affected the lungs.

Answer 1

"During inhalation, the diaphragm contracts downward, and rib muscles pull upward, causing air to fill the lungs. (This increases the volume of the thoracic cavity and decreases pressure in the lungs — the air will flow from the higher pressure environment to lower pressure area in the lungs.) "

"When you pull down on the diaphragm, you increase the volume of the bell jar, thus lowering the pressure. Air is then forced into the “lungs” from outside, lowering the volume in the bell jar (and stretching the balloons) until the pressures inside and outside the bell jar are equal."