The Respiratory System By: Mitchell Gwynn

Terms Alveoli – provide surface area for gas exchange in mammals Diaphragm – muscle that draws air to lungs Air sacs – pockets that hold extra air in birds

Fish Fish breathe through their gills Water comes in mouth, passes over gills, and out through operculum. Oxygen enters their bloodstream through diffusion. Some fish can breathe air through a simple lung which diffuses in the blood.

Amphibians In aquatic stage, they breathe through gills As adults, they breathe through lungs, skin or both. Some have a primitive lung structure and must rely on diffusion of oxygen through skin. They must stay moist. Some have more efficient lungs and don’t rely on breathing through their skin.

Reptilia Breathe through lungs that are more developed than an amphibian.

Aves Also have lungs. Connected to their lungs are air sacs. When a bird inhales the air goes to the lungs and rear air sacs. When a bird exhales, the air in the lungs moves to the front air sacs and the air from the rear sacs move into the lungs.

Mammalia Have lungs with alveoli which increase surface area for gas exchange. Also have a diaphragm.