The figure above shows a model of lungs using a pair of balloons and an elastic membrane-tethered to a bottle whose wide end has been removed. When the elastic membrane is pulled, the red balloons expand. The elastic membrane represents which part of the respiratory system?
The figure above shows a model of lungs using a pair of balloons and an elastic membrane-tethered to a bottle whose wide end has been removed. When the elastic membrane is pulled, the red balloons expand. The elastic membrane represents which part of the respiratory system?
The correct option is D Diaphragm
The elastic membrane represents the diaphragm. The lungs (represented by the balloons) expand when the diaphragm is pulled down. Pulling of the diaphragm down increases the volume of the chest cavity, creating a low pressure. Thus, air which is at a higher pressure outside rushes into the lungs causing them to expand.
The reverse happens when the diaphragm moves upwards towards the lungs. In our body the rib cage also moves to help us breathe, but this model is simplistic and only shows the diaphragm.
Diaphragm
The elastic membrane represents the diaphragm. The lungs (represented by the balloons) expand when the diaphragm is pulled down. Pulling of the diaphragm down increases the volume of the chest cavity, creating a low pressure. Thus, air which is at a higher pressure outside rushes into the lungs causing them to expand.
The reverse happens when the diaphragm moves upwards towards the lungs. In our body the rib cage also moves to help us breathe, but this model is simplistic and only shows the diaphragm.
