The rib cage expands to help move air into the lungs.
The correct answer and explanation is:
The rib cage plays a crucial role in the respiratory process by aiding the expansion and contraction of the lungs, which is essential for breathing. The expansion of the rib cage allows the lungs to take in air, while its contraction helps expel air from the lungs. This process is part of the mechanical process of ventilation, which is vital for respiration.
When a person inhales, the diaphragm, a large muscle beneath the lungs, contracts and moves downward. Simultaneously, the intercostal muscles, which are located between the ribs, contract, lifting the ribs upward and outward. This movement increases the volume of the chest cavity, creating a lower pressure inside the lungs compared to the external environment. As a result, air rushes into the lungs to equalize the pressure, filling the alveoli (the tiny air sacs in the lungs) with oxygen.
On the other hand, during exhalation, the diaphragm relaxes and moves upward, and the intercostal muscles relax as well, causing the rib cage to move inward and downward. This reduction in the chest cavity volume increases the pressure inside the lungs, forcing air out. The process of inhalation and exhalation is continuous and essential for oxygenating the blood and removing carbon dioxide from the body.
The ability of the rib cage to expand and contract is also influenced by various factors, such as age, physical condition, and health conditions like asthma or chronic obstructive pulmonary disease (COPD). People who are physically fit generally have more efficient lung capacity and stronger muscles for breathing, while individuals with respiratory conditions may struggle to fully expand their rib cage, making it harder to take in enough air.