Alveolar sac

The Alveolar sac (pronounced: al-vee-uh-lar sak) is a structure found within the respiratory system of mammals, including humans. It is the terminal end of the respiratory tree and is where gas exchange occurs.

Etymology

The term "alveolar" is derived from the Latin word "alveolus", meaning "small cavity". The term "sac" is derived from the Latin word "saccus", meaning "bag" or "sack".

Function

The primary function of the alveolar sac is to facilitate the exchange of gases between the air in the lungs and the blood in the capillaries. This process is known as respiration.

Structure

The alveolar sac is composed of two or more alveoli, which are small, balloon-like structures where gas exchange occurs. Each alveolus is surrounded by a network of capillaries, which carry oxygen-depleted blood from the body to the lungs, and oxygen-rich blood from the lungs to the body.

Related Terms

Alveoli: The individual units within the alveolar sac where gas exchange occurs.
Respiratory system: The system of organs responsible for taking in oxygen and expelling carbon dioxide.
Respiratory tree: The branching system of airways leading from the trachea to the alveoli.
Capillaries: The smallest blood vessels, which connect the alveoli to the rest of the body.
Respiration: The process of exchanging gases between the body and the environment.