Human Respiratory System - Worksheet | Printable and Distance ... - Free Printable

Problem Analysis:

The task involves two parts:
1. Labeling the parts of the human respiratory system in the provided diagram.
2. Identifying the site of gas exchange in the lungs from the given options.

---

Solution:

#### Part 1: Labeling the Parts of the Human Respiratory System
The diagram shows various parts of the respiratory system, and we need to match the labels with the correct anatomical structures. Here is the explanation for each label:

1. Nose: The external opening for air intake. It is correctly labeled in the diagram.
2. Nasal cavity: The internal space behind the nose where air passes through. It is correctly labeled.
3. Mouth: The alternative opening for air intake. It is correctly labeled.
4. Throat: The passageway connecting the mouth and nasal cavity to the larynx. It is correctly labeled.
5. Epiglottis: A flap of tissue that covers the trachea during swallowing to prevent food from entering the lungs. It is correctly labeled.
6. Larynx: Also known as the voice box, it houses the vocal cords. It is correctly labeled.
7. Trachea: The windpipe that carries air to and from the lungs. It is correctly labeled.
8. Esophagus: The tube that transports food from the throat to the stomach. It is correctly labeled.
9. Bronchi: The two main branches of the trachea that lead into the lungs. They are correctly labeled.
10. Bronchiole: Smaller branches of the bronchi within the lungs. They are correctly labeled.
11. Alveoli: Tiny air sacs in the lungs where gas exchange occurs. They are correctly labeled in the inset diagram.
12. Lungs: The primary organs of respiration where gas exchange takes place. They are correctly labeled.

All the labels in the diagram are accurate based on the provided terms.

---

#### Part 2: Identifying the Site of Gas Exchange in the Lungs
The question asks where gas exchange occurs in the lungs. Let us analyze the options:

- a) Larynx: This is the voice box located above the trachea. It is not involved in gas exchange.
- b) Bronchi: These are the main branches of the trachea that divide into smaller bronchioles. While they transport air, they are not the site of gas exchange.
- c) Alveoli: These are tiny air sacs in the lungs surrounded by capillaries. Gas exchange (oxygen entering the blood and carbon dioxide leaving the blood) occurs here.
- d) Trachea: This is the windpipe that carries air to and from the lungs. It is not involved in gas exchange.

The correct answer is c) Alveoli because they are the site where oxygen diffuses into the bloodstream and carbon dioxide diffuses out.

---

Final Answer:

For Q.4:
$$
\boxed{c}
$$