LUNGS
• Diaphragm—muscle under the lungs
• Lungs take in oxygen and release carbon dioxide
• Mammals, birds, most reptiles and amphibians

GILLS
• Filter oxygen from the water—H
2
O
• Examples: fish and some amphibians

Is this an animal? What does it use to breathe?

SKIN
• Some animals take in oxygen through their skin
• Examples: flatworm or earthworm

The Respiratory System
1. Oxygen (O2) enters the nose or mouth
2. It travels through the pharynx and larynx down the trachea or windpipe.

3. Next, oxygen enters into two bronchial tubes, or bronchi , that lead to the lungs.
4. Inside the lungs the O2 passes through tiny air sacs called alveoli into the blood.

YES!! Plants breathe!
The plant takes in carbon dioxide and releases oxygen through stomata.
--Tiny openings on the bottom of the leaf.

• Supplies cells with the oxygen they need to perform cellular respiration
–Gets rid of CO
2

• Lungs-get oxygen from the air to the blood
• Diaphragm-large muscle that helps bring air into the lungs

• Gills-organs that remove oxygen from the water (H
2
O)
–Oxygen passes through gills to the blood
–Gills remove CO
2