The respiratory system in human beings is responsible for the exchange of oxygen and carbon dioxide between the body and the environment. It consists of several organs and structures, including:
1. Nose and Nasal Cavity: The nose and nasal cavity act as the entry point for air. They filter, warm, and moisten the incoming air.
2. Pharynx: The pharynx, or throat, is a muscular tube that connects the nasal cavity and mouth to the larynx. It serves as a passage for both air and food.
3. Larynx: The larynx, or voice box, is located below the pharynx. It contains vocal cords that vibrate to produce sound.
4. Trachea: The trachea, or windpipe, is a tube that connects the larynx to the bronchi. It is lined with cilia and mucus-producing cells that help trap and remove foreign particles.
5. Bronchi: The trachea divides into two bronchi, one leading to each lung. The bronchi further divide into smaller bronchioles, which eventually lead to tiny air sacs called alveoli.
6. Lungs: The lungs are the main organs of the respiratory system. They are located in the chest cavity and are responsible for the exchange of gases. The right lung has three lobes, while the left lung has two lobes.
7. Alveoli: The alveoli are small, thin-walled air sacs located at the end of the bronchioles. They are surrounded by capillaries and are the site of gas exchange. Oxygen from the air enters the bloodstream, while carbon dioxide from the bloodstream is expelled into the air.
8. Diaphragm: The diaphragm is a dome-shaped muscle located at the base of the chest cavity. It plays a crucial role in breathing by contracting and relaxing, causing changes in lung volume and air pressure.
The respiratory system works in coordination with the circulatory system to ensure the delivery of oxygen to the body's cells and the removal of carbon dioxide.