1. Nose: Mammals breathe through their noses. The nose is the entry point for air, and it contains hairs and mucus that help filter dust, pollen, and other particles from the incoming air.
2. Pharynx: The pharynx, also known as the throat, is a muscular tube that connects the nasal passages to the larynx and esophagus. It serves as a passageway for both air and food.
3. Larynx: The larynx, commonly called the voice box, is located at the top of the trachea. It contains vocal cords that vibrate to produce sound when air passes through them.
4. Trachea: The trachea is a long, flexible tube that connects the larynx to the lungs. It is lined with ciliated cells that help remove dust and particles from the incoming air.
5. Bronchi: The trachea branches into two bronchi, one leading to each lung. The bronchi are further divided into smaller branches called bronchioles.
6. Lungs: The lungs are two large, spongy organs located on either side of the heart. They contain millions of tiny air sacs called alveoli, where gas exchange occurs.
7. Diaphragm: The diaphragm is a large muscle located at the bottom of the ribcage. It plays a crucial role in breathing by contracting and relaxing to draw air in and out of the lungs.
Breathing in a mammal follows this basic process:
- Inhalation: The diaphragm contracts, pulling the ribcage up and expanding the chest cavity. This creates negative pressure in the lungs, causing air to rush in through the nose or mouth.
- Exhalation: The diaphragm relaxes, and the ribcage moves downward, reducing the volume of the chest cavity. This pushes the air out of the lungs through the nose or mouth.
When a mammal inhales, oxygen from the air diffuses across the thin walls of the alveoli into the bloodstream. Simultaneously, carbon dioxide, a waste product of metabolism, diffuses from the bloodstream into the alveoli to be exhaled. This process of gas exchange ensures that the body receives a constant supply of oxygen and eliminates carbon dioxide.
The respiratory system in mammals is a complex network of organs and tissues that work together to facilitate efficient gas exchange and maintain proper oxygen and carbon dioxide levels in the body.