The Respiratory System - Worksheets | Teach Starter - Free Printable

Based on the analysis of the provided diagram, here is a complete solution explaining the parts of the human respiratory system shown:

The image is a labeled diagram illustrating the key components of the human respiratory system. The system's primary function is to facilitate gas exchange—bringing oxygen into the body and expelling carbon dioxide.

Here is a breakdown of each labeled part and its function:

1. Mouth: This is one of the two main entry points for air into the body. Air can be inhaled through the mouth, especially during heavy breathing or when the nasal passages are blocked.
2. Nasal Cavity: This is the other primary entry point for air. The nasal cavity warms, humidifies, and filters the incoming air before it travels further down the respiratory tract.
3. Trachea (Windpipe): This is a tube-like structure that connects the larynx (voice box) to the bronchi. It serves as the main passageway for air to travel from the throat to the lungs.
4. Bronchi: These are the two main branches that extend from the trachea, one leading to each lung. They further divide into smaller tubes called bronchioles within the lungs.
5. Lung: These are the primary organs of the respiratory system. They are spongy, air-filled organs where the critical process of gas exchange occurs.
6. Alveoli: These are tiny, balloon-like sacs located at the very end of the bronchioles within the lungs. They are the site of gas exchange. Oxygen from the inhaled air diffuses through the thin walls of the alveoli into the surrounding capillaries (tiny blood vessels), while carbon dioxide, a waste product, diffuses from the blood into the alveoli to be exhaled.

In summary, the diagram shows the pathway air takes: it enters through the mouth or nasal cavity, travels down the trachea, branches into the bronchi, and finally reaches the lungs where gas exchange happens in the alveoli.