Identify the parts of respiratory tract without 'C' shaped cartilages.

Options

A. Trachea
B. Primary bronchi
C. Secondary bronchi
D. Terminal bronchioles

Answer

To identify the parts of the respiratory tract that do not have 'C' shaped cartilages, we will follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of the Respiratory Tract**:
The respiratory tract consists of various parts including the trachea, primary bronchi, secondary bronchi, tertiary bronchi, and bronchioles.

2. **Identify Parts with 'C' Shaped Cartilage**:
- The **trachea** is the main airway that has 'C' shaped cartilage to maintain its structure.
- The **primary bronchi**, which branch off from the trachea, also contain 'C' shaped cartilage.
- The **secondary bronchi** and **tertiary bronchi** continue to have 'C' shaped cartilage as well.

3. **Examine the Bronchioles**:
- The bronchioles are smaller branches of the bronchi. They are categorized into **initial bronchioles** and **terminal bronchioles**.
- The **initial bronchioles** still contain some cartilage, but as they progress to the **terminal bronchioles**, the cartilage is no longer present.

4. **Conclusion**:
- Among the parts listed, the **terminal bronchioles** are the only part of the respiratory tract that does not have 'C' shaped cartilage. Thus, the answer to the question is the terminal bronchioles.

### Final Answer:
The part of the respiratory tract without 'C' shaped cartilages is the **terminal bronchioles**.

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