Week 3 : Gas exchange

Simple Diffusion

Gas exchange directly across the body surface

Ectoderm

Outer body layer that can be used for gas exchange

Specialized Ventilatory structures

Specialized structures used for gas exchange, such as lungs and gills

Respiratory Exchange Membrane

Seperates the animal’s internal tissue from the evironment and allows gases to cross

Partial pressure

Pressure of one specific gas in a mixture

diffusion

Movement of gasses from high partial pressure to low partial pressure

Ventilation

Movement of air or water across a respiratory surface

Lungs

Specialized structures for gas exchange with air

Gills

specialized strcuture for gas exchange with water

Negative pressure

A change in volume that creates pressure diiference and helps move air into the lungs

Body size

A factor that afffects how an animal gets oxygen across its respiratory membrane

Metabolic Demands

The amount of oxygen an animal needs based on its energy use

Evironment

A factor that affects how an animal exchanges gases

Lung Ventilation

Movement of air into and out of the lung

Gill Ventilation

Movement of water across the gills

O2 Movement

Oxygen moves from the evironment toward the tissue

CO2 Movement

Carbon dioxide moves from the tissue toward the evironment

Small/ Simple animals

often rely on simple diffusion across their body surface

Large/ Active animals

Usually need specialized respiratory structures

Main Goal of Gas exchange

Move oxygen from the evironment to the tissues and remove carbon dioxide

Key rule

Gases move from high partial pressure to low partial pressure

Main factors

• body size

• metabolic demands

• Environment afffect how animals get oxygen