» Current Location: Respiratory System

» The diaphram is a muscle  » The lungs are protected by the ribs  » Look inside the mouth and examine a tooth  »    » Go up one layer to the trachea, lungs and heart  »    »    »    »

Ready to conjure up our Respiratory System Self-Quiz?

This is the respiratory system. Without this system, you couldn't breathe! Here's how it works...

• Although it may seem easier to breathe through the mouth, it is healthier to breathe through the nose. The hairs and mucus in the nose (part of the nasal cavity) help filter and warm the air as it comes in.

• The epiglottis is a small flap of tissue above the trachea that prevents food from entering the trachea and lungs.

  • At the lower end of the trachea are two short branches called bronchi, that carry air into the lungs.

  • Within the lungs, the bronchi branch into smaller and smaller tubes called bronchioles.

  • At the end of each bronchiole are clusters of tiny, thin-walled sacs called alveoli.

  • The exchange of oxygen and carbon dioxide takes place between the alveoli and the surrounding capillaries.

  • The diaphragm is a muscle beneath the lungs that helps move air in and out of the body.