What is the difference between inhalation and exhalation?

Inhalation is the process of breathing in air, while exhalation is the process of breathing out air.

During inhalation, the diaphragm and intercostal muscles contract, causing the chest cavity to expand and the lungs to fill with air. This process is driven by a decrease in pressure within the lungs, which draws air in through the nose or mouth. The air is then warmed, filtered, and moistened as it passes through the nasal passages and into the lungs.

Exhalation, on the other hand, is the process of expelling air from the lungs. This occurs when the diaphragm and intercostal muscles relax, causing the chest cavity to decrease in size and the lungs to push air out. The air is then expelled through the nose or mouth, carrying with it carbon dioxide and other waste products that have accumulated in the lungs.

The process of inhalation and exhalation is controlled by the respiratory centre in the brainstem, which regulates the rate and depth of breathing based on the body's needs for oxygen and removal of carbon dioxide. The respiratory system also works in conjunction with the cardiovascular system to transport oxygen and nutrients to the body's tissues and remove waste products.

In summary, inhalation and exhalation are two essential processes of respiration that work together to ensure the body receives the oxygen it needs and eliminates waste products.