1. Nose and Mouth: Air enters the body through the nostrils or the mouth. The nose is preferred as it filters, warms, and humidifies the air.
2. Pharynx: The air travels through the pharynx, a passageway at the back of the throat that is shared with the digestive system.
3. Larynx (Voice Box): The air moves down the larynx, which contains the vocal cords.
4. Trachea (Windpipe): The air continues into the trachea, a tube lined with cilia and mucus that further cleanses the air.
5. Bronchi: The trachea branches into two bronchi, one leading to each lung.
6. Bronchioles: Each bronchus further divides into smaller tubes called bronchioles.
7. Alveoli: The bronchioles finally terminate in tiny air sacs called alveoli. These tiny sacs are surrounded by capillaries, where gas exchange takes place.
Gas Exchange:
* Oxygen: Oxygen from the inhaled air diffuses across the thin walls of the alveoli and into the capillaries, where it binds to red blood cells and is carried throughout the body.
* Carbon Dioxide: Carbon dioxide, a waste product of cellular respiration, travels from the blood in the capillaries to the alveoli and is exhaled.
Mechanism of Inhalation:
The act of breathing in is controlled by the diaphragm and intercostal muscles.
* Diaphragm: This dome-shaped muscle contracts, flattening and pulling air into the lungs.
* Intercostal Muscles: These muscles between the ribs help expand the chest cavity, creating more space for the lungs to fill with air.
Exhalation:
Exhalation is the opposite of inhalation. The diaphragm relaxes and the chest cavity shrinks, forcing air out of the lungs.
Let me know if you'd like to know more about any part of this process!
