What happens during breathing?

Breathing, also known as respiration, is a vital process that brings oxygen into the body and removes carbon dioxide. It involves two main stages: inhalation and exhalation.

1. Inhalation (Breathing In):

- During inhalation, the diaphragm contracts and moves downward, while the intercostal muscles between the ribs contract to lift the ribcage.

- As a result, the volume of the thoracic cavity increases, and the pressure inside decreases.

- Air is drawn into the lungs through the nose or mouth, passing through the pharynx, larynx, and trachea.

- The trachea divides into two primary bronchi, which enter the left and right lungs. Inside the lungs, the bronchi branch further into smaller bronchioles.

- The bronchioles end in tiny air sacs called alveoli. The alveoli have a large surface area made up of thin, delicate capillaries.

2. Exhalation (Breathing Out):

- During exhalation, the diaphragm relaxes and moves upward, while the intercostal muscles also relax to lower the ribcage.

- The volume of the thoracic cavity decreases, and the pressure inside increases.

- This compression forces air out of the lungs through the same pathway it took during inhalation (bronchioles, bronchi, trachea, larynx, pharynx, mouth or nose).

- As the diaphragm contracts, it also assists in expelling air from the lungs.

Gas Exchange:

The main purpose of breathing is to facilitate gas exchange between the air and the bloodstream. Oxygen from the inhaled air passes from the alveoli into the capillaries that surround them. At the same time, carbon dioxide, a waste product produced by cellular respiration, diffuses from the capillaries into the alveoli. This process ensures that oxygen-rich blood is distributed to the body's tissues, while carbon dioxide is transported to the lungs to be exhaled.

Regulation of Breathing:

Breathing is primarily regulated by the respiratory center in the brainstem, particularly the medulla oblongata and the pons. This center controls the rate and depth of respiration based on various factors, such as the levels of carbon dioxide, oxygen, and pH in the blood. When the levels of these gases change, the respiratory center adjusts the rate and depth of breathing to maintain proper oxygen and carbon dioxide levels.