Question

Select the correct statements:
1) The air sac of each tertiary bronchi shows 10 to 12 alveoli.
2) Each alveolus is surrounded by a network of capillaries.
3) They are lined by ciliated pseudostratified epithelium.
4) They provide surface area for the exchange of gases.
5) There are about 700 million alveoli.

• A. 1, 2, 4, 5
• B. 1, 3, 4, 5
• C. 2, 4, 5
• D. 1, 2, 3, 4

Hint:

The alveoli are essential for efficient gas exchange in the lungs. Their structure, including a thin epithelium and surrounding capillaries, maximizes surface area for diffusion.

Answer 1

The Correct Option is A

Step 1: The bronchi are part of the airway system that leads to the lungs. The tertiary bronchi, which branch off the secondary bronchi, lead to smaller air sacs called alveoli. Each tertiary bronchi has about 10 to 12 alveoli associated with it.
Step 2: Alveoli are tiny air sacs surrounded by a dense network of capillaries, which facilitate the exchange of gases (oxygen and carbon dioxide). This is crucial for respiration.
Step 3: Alveoli are lined with simple squamous epithelium, not pseudostratified ciliated epithelium. The pseudostratified ciliated epithelium is found in the upper respiratory tract.
Step 4: Alveoli provide a vast surface area for gas exchange and play a key role in respiration. There are approximately 700 million alveoli in the human lungs, which increases the surface area for gas exchange.
Conclusion: The correct statements are 1, 2, 4, and 5.