2. GAS EXCHANGE Summary on system cards

3. Card No 1 Definitions Make them short and sharp Underline or highlight key words It may be easier sometimes to draw and label a diagram

4. Choosing the content of your card Glance over the objectives and group closely related objectives together For example, Gas Exchange can be grouped into four main themes:  Gas exchange in general  Gas exchange in plants  Gas exchange in animals  Gas exchange in mammals (humans)

5. Gas Exchange in General Air 1 L contains 210 mL of O 2 as altitude , density of air  in micro- environments, [O 2 ] is less and [CO 2 ] is greater greater chance of respiratory surfaces drying out Water 1 L contains 7 mL of O 2 as temperature , salinity , or depth , amount of gas that can dissolve  (including oxygen) less chance of respiratory surfaces drying out

6. Gas Exchange in Plants Leaves stomata (include diagram) Stem lenticels (include diagram) Roots get gases from the air spaces in the soil gases diffuse into the film of moisture surrounding the root hairs

7. Gas Exchange in Animals Breathing in Air insects have: –tracheae, branching tubes –spiracles, holes in the cuticle frogs exchange gases by: –absorbs through skin –gulping movements of the throat and floor of the mouth Breathing in Water gills composed of: –several gill arches –gill arches contain gill filaments –the gill lamellae is a section of the filament where gas is exchanged cilia can be used to move water most have muscular pump to ventilate gills