Which type of epithelial tissue is shown in the image, characterized by a single layer of flat cells lining the air sacs of the lungs?

• A. Transitional epithelium
• B. Stratified squamous epithelium
• C. Simple squamous epithelium
• D. Simple cuboidal epithelium

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the characteristics of epithelial tissues. Epithelial tissues are classified based on the number of layers (simple or stratified) and the shape of the cells (squamous, cuboidal, or columnar). Simple epithelium has a single layer of cells, while stratified epithelium has multiple layers.
2. Step 2: Focus on the description provided in the problem. The tissue is described as a single layer of flat cells lining the air sacs of the lungs. This indicates it is a simple epithelium because it has only one layer of cells.
3. Step 3: Identify the shape of the cells. Flat cells are characteristic of squamous epithelium. Squamous cells are thin and flat, allowing for efficient gas exchange, which is essential in the lungs.
4. Step 4: Match the description to the correct type of epithelial tissue. Simple squamous epithelium is specifically adapted for diffusion and filtration, making it ideal for lining structures like the air sacs of the lungs (alveoli).
5. Step 5: Eliminate the other options. Transitional epithelium is found in areas like the bladder and is specialized for stretching. Stratified squamous epithelium is multilayered and found in areas subject to abrasion, like the skin. Simple cuboidal epithelium consists of cube-shaped cells and is found in glands and kidney tubules, not the lungs.