Question

The size of the chest cavity increases during inhalation.
(A) True
(B) False

Answer 1

Hint: The lungs is the organ of the respiration. The respiration takes place in the two stages as the inhalation and the exhalation. The inhalation deals with the breathing in of the oxygen and the exhalation deals with the leaving out of the carbon dioxide as the metabolic waste product.

Complete Answer:
The thoracic pit, or chest cavity maintains the negative pressure which helps in keeping the aviation routes of the lungs open.
During the cycle of inward breath, the lung volume grows because of the constriction of the stomach and intercostal muscles (the muscles that are associated with the rib confine), consequently extending the thoracic cavity.
During this cycle, the diaphragm extends out and away from the lungs. The lungs are flexible; in this way, when air fills the lungs, the versatile force inside the tissues of the lung applies pressure back toward the inside of the lungs. These outward and internal powers contend to swell and empty the lung with each breath. Hence the chest cavity increases.

Upon exhalation, the intercostal muscles unwind, restoring the diaphragm to its unique position. During exhalation, the stomach likewise unwinds, moving higher into the thoracic cavity. Air surges out of the lungs because of the weight slope between the thoracic pit and the external environment. This causes the decrease in the area of the chest cavity.

Thus, the option (A) is correct.

Note: During the breathing in of the air, the ribs move upward and outward but during the breathing out the rib cage moves downward and the inward. The exchange of the gases takes place in the balloon like structures in the lungs called alveoli surrounded by the blood capillaries.