4.
The respiratory system is responsible for gas exchange, supplying the body with oxygen and removing carbon dioxide. It consists of the nasal passages, pharynx, larynx, trachea, bronchi, and lungs.
| Nasal Passages and Pharynx: | Air enters the body through the nasal passages, where it is filtered, warmed, and humidified. The pharynx, a shared pathway for both air and food, directs the inhaled air toward the larynx and trachea. |
| Larynx and Trachea: | The larynx, or voice box, houses the vocal cords and is involved in sound production. The trachea, or windpipe, is a tube that conducts air from the larynx to the bronchi and lungs. |
| Bronchi and Lungs: | The trachea divides into two bronchi, which enter the lungs. Within the lungs, the bronchi further divide into smaller bronchioles, ending in clusters of alveoli. Alveoli are tiny air sacs where the exchange of oxygen and carbon dioxide occurs between the air and the blood. Oxygen is absorbed into the bloodstream, and carbon dioxide is expelled from the body during exhalation. |
| Respiratory Muscles: | The diaphragm and intercostal muscles play a crucial role in breathing. The diaphragm is a dome-shaped muscle that contracts during inhalation, creating a vacuum that draws air into the lungs. The intercostal muscles, located between the ribs, assist in expanding and contracting the chest cavity during breathing. |