Understand how gas pressure influences how gases move into and out of the body

The structure of the lung maximizes its surface area to increase gas diffusion. Because of the enormous number of alveoli (approximately 300 million in each human lung), the surface area of the lung is very large (75 m²). Having such a large surface area increases the amount of gas that can diffuse into and out of the lungs.

What You’ll Learn to Do

• Identify the basic principles of gas exchange
• Name and describe lung volumes and capacities
• Describe how gas pressure influences how gases move into and out of the body
• Discuss how gases move across the alveoli

Learning Activities

The learning activities for this section include the following:

• Breathing Capacity
• Gas Pressure and Respiration
• Gas Exchange across the Alveoli
• Self Check: Gas Exchange across Respiratory Surfaces