Respiration

Respiration

Gas Exchange

• Gas Exchange: taking in O2 and releasing CO2
• Ventilation: movement of air or water over respiratory surface
• Surface must be moist
• Uses diffusion
• Larger surface area = more gas exchange
• Thinner membrane = more gas exchange

Types of Respiratory Systems

Gills

• Aquatic animals often use gills
• Countercurrent exchange: maximizes gas exchange
• Blood and water flow in opposite directions

Tracheal Systems

• Tracheal System: a network of tubes that carry air throughout the body
• Largest tube is the Trachea, which is open to air
• Insects have many trachea that contact every cell directly
• Enables expensive movements (i.e. flight)
• Most mammals use Lungs: a specialized respiratory organ
• Lungs are open to the air
• Have many pockets to increase gas exchange
• Must use circulatory system to transport O2 to the body

Mammalian Respiratory System

• Air enters the Trachea
• The trachea splits into Bronchi which lead into each lung
• Bronchi branch into smaller Bronchioles
• Bronchioles end in Alveoli: air sacs where gas exchange occurs
• Alveoli are covered in Surfactant: which prevents them from collapsing