Please experts provide the reason for it
Dear student
Expiration involves removal of CO2 from the body. When we breathe out, the size of our chest decreases. This happens because when air moves out of our lungs, the lungs contract,the ribs move back, and the diaphragm curves upwards into the chest decreasing the size of the chest. The internal intercostal muscles ( IICM ) assist with active expiration by pulling the ribs down and in, thus decreasing thoracic volume. Muscles of the abdominal wall drive intra-abdominal pressure up when they contract, and thus push up the diaphragm, which in turn drives air out.
Thus, ( 3) is the right answer.
Hope this helps!
Regards
Expiration involves removal of CO2 from the body. When we breathe out, the size of our chest decreases. This happens because when air moves out of our lungs, the lungs contract,the ribs move back, and the diaphragm curves upwards into the chest decreasing the size of the chest. The internal intercostal muscles ( IICM ) assist with active expiration by pulling the ribs down and in, thus decreasing thoracic volume. Muscles of the abdominal wall drive intra-abdominal pressure up when they contract, and thus push up the diaphragm, which in turn drives air out.
Thus, ( 3) is the right answer.
Hope this helps!
Regards