Amphibians

Respiratory System

Lungs, skin, and sometimes gills

Description

Amphibians can get oxygen into their bodies in three different ways. The first way is by using lungs, which are similar to ours. The second way is through their skin, and the last way is by using gills.

Amphibians, like reptiles, are cold blooded, so they don't use up any energy by keeping their bodies at a constant temperature. This means their cells aren't working as hard as warm blooded animals like us, and they don't need as much oxygen. Because of this, amphibians don't breathe constantly like humans do. Instead, they just breathe now and then, when their body needs more oxygen.

Amphibian lungs are a bit different from our lungs. Our lungs are spongy, and full of tiny little sacs called alveoli. These alveoli increase the amount of surface that oxygen can enter our bodies through. Since amphibians don't need as much oxygen as humans, they don't have as many alveoli, either! In fact, many amphibians have lungs that are just two hollow sacs!

The way amphibians use their lungs is different from humans, too. Humans have a diaphragm beneath their lungs, that causes the air to rush in and out. Amphibians don't have diaphragms, and they have to force air into their lungs by moving their mouth -- sort of like swallowing.

Amphibians can also get oxygen through their skin! The skin on amphibians is very thin, and it allows water to go through it. The water carries oxygen with it, and into the amphibian's body! Since humans have water-proof skin, we aren't able to breathe through it.

Many amphibians have gills, at least when they're young. Gills are made up of very thin blood vessels, surrounded by water channels. When water flows through the gills, the oxygen it contains crosses the very thin blood vessel walls, and into the blood. See the fish page for more information about gills.

Neat Stuff

Although the thin skin on amphibians allows water to enter their bodies so they can get oxygen, it also allows water to leave their bodies when they're in a dry environment. That's why most amphibians have to live in moist places, where there's water near by. Since humans have water-proof skin, we can live out of the water our entire lives, but it means we can't breathe through our skin.