1. Nasal Cavity: The air first enters the nasal cavity, which is lined with mucous membranes that help trap dust, dirt, and other particles. The nasal cavity also helps regulate the temperature and humidity of the incoming air.
2. Pharynx: From the nasal cavity, the air moves to the pharynx, a muscular tube that connects the nasal passages and mouth to the larynx and esophagus.
3. Larynx (Voice Box): The air passes through the larynx, which contains vocal cords that vibrate to produce sound.
4. Trachea (Windpipe): Below the larynx is the trachea, a tube made up of cartilage rings that supports the airway. The trachea carries the air to the lungs.
5. Bronchi: The trachea branches into two bronchi, one leading to each lung.
6. Bronchioles: Each bronchus further divides into smaller tubes called bronchioles, which branch and become narrower as they penetrate deeper into the lungs.
7. Alveoli: The bronchioles end in tiny sacs called alveoli. The alveoli are lined with capillaries, which are small blood vessels where oxygen and carbon dioxide exchange takes place.
8. Lungs: The lungs contain millions of alveoli, providing an extensive surface area for gas exchange. The alveoli are where the respiratory system exchanges oxygen and carbon dioxide with the bloodstream. Oxygen from the inhaled air diffuses across the alveoli into the capillaries, while carbon dioxide diffuses from the capillaries into the alveoli to be exhaled.
After the gas exchange process, the air, now depleted of oxygen and rich in carbon dioxide, follows the same pathway in reverse order and is exhaled out of the body. This completes one respiratory cycle.
