Alveolar sacs

Definition

Alveolar sacs are tiny, balloon-like structures located at the ends of the respiratory tree within the lungs. They serve as the primary site for gas exchange between the air and blood.

5 Must Know Facts For Your Next Test

1. Each alveolar sac contains multiple alveoli, which increase surface area for gas exchange.
2. Surfactant produced by cells in the alveolar sacs reduces surface tension, preventing collapse.
3. Alveolar sacs are surrounded by a network of capillaries where oxygen and carbon dioxide are exchanged.
4. The thin walls of alveoli facilitate rapid diffusion of gases.
5. Diseases like emphysema can damage alveolar sacs, reducing their efficiency.

Review Questions

• What is the primary function of alveolar sacs?
• How does surfactant benefit the alveolar sacs?
• What happens in diseases that affect the alveolar sacs?

Related terms

Alveoli: Tiny air-filled pockets within alveolar sacs that facilitate gas exchange.

Surfactant: A substance produced in the lungs that reduces surface tension within alveoli.

Capillaries: Small blood vessels surrounding each alveolus where gas exchange occurs.