The main function of the respiratory system is the transferring of gases between the air and the blood.

The system is comprised of tubes and highly branched channels which terminate in dead-end sacs where gas transfer occurs. Air brought into the body is first conditioned and filtered in the first part of the respiratory system, the conducting portion (nasal cavity to bronchioles). The second part of the system, the respiratory portion, consists of the respiratory bronchioles and alveoli are involved with gas exchange.

Learning Objectives:

• Understand the general organization of the respiratory system and recognize LM preparations of the various regions.
• Understand the structure and functional significance of respiratory alveoli.
• Recognize the different cell types in an alveolus

Let's start at the top with the nasal cavity.