Lungs

Today, a girl named Samantha and her father came into Doctor Glycine's office with her stump-eater, Casey.
Casey was sick, and couldn't breathe very well.

A Stump-Eater is an animal from the planet Sopreevo. They eat wood, usually you can find them chewing on a tree stump, that is why they are called stump-eaters.
Stump-eaters have four legs, and one head, sticking out of a hard shell, like a turtle.
But they are not turtles!
People say a turtle carries it's house on it's back, and so does a stump eater, but a stump eater also carries it's lung on it's back.

The lung is the part of the body, or organ, that lets an animal breathe air. Most animals have lungs inside their body, and tubes to let the air get in and out. Stumpeaters have their lung on the top of their shell, with just a hole to breathe through.
The lung is like a bag that holds air. There is a breathing muscle that makes the lung get big or small. When the lung gets big, good air comes in, and goes into the animals' blood. When the lung gets small, bad air gets pushed out.

Samantha said Casey didn't want to play anymore, and kept his head inside his shell. Doctor Glycine looked at Casey.
He shined a light in casey's eyes,
and wanted to shine a light into casey's mouth,
but Casey wouldn't open his mouth
or even stick his head out!
Next, Doctor Glycine looked into Casey's breathing hole.
"Aha!" he said.
"What is it?" Asked Samantha.
"The inside of Caseys breathing hole is yellow, but it should be purple.
He has an infection. His aveoli are getting clogged."
"Oh no!" Samantha said "What are those?"

Aveoli are tiny air sacs in the lung that do the job of gas exchange: putting air into the blood, and taking it out again. Lungs are not just one big bag, they are millions of [many, many] individual mini-lungs. This make lungs transfer a lot more air. If lungs were hollow, like an ordinary bag, blood could only flow on the outside surface. By having lots of aveoli, the middle parts of the lung are also used. The aveoli are connected to the breathing hole with brochial tubes, or 'bronchi' that branch out from te breathing hole.

On earth some animals, like frogs, do not have aveoli. They can still survive because they do not need much oxygen, and they also absorb some oxygen directly through their skin.

Samantha thought about this, and asked a question, "Is my lung just like Casey's?"

• You have two lungs, one on your Left side, and one on your Right side, Casey only has one.
• Casey has a breathing muscle that sqeezes his lung to push out the bad air, but you have a breathing muscle called a diaphragm that expands your chest, so the lungs suck in air.
• Your lungs are inside your body, so you have a tube called a trachea that goes from your lung to the bottom of your throat. You breathe through the same hole you eat through.
• Casey does not breathe through his mouth, and he does not have a nose!

Doctor Glycine did a few other tests to make sure he was right about the infection. Machines went BEEP BEEP BEEP, and told him he was right. He gave Samantha's father a bottle of a medicine called an antibiotic.
"Put a capful of this into a fresh bowl of water every day. Keep doing it for two weeks, even after he gets better"
"Will it take long?" Samantha asked.
"No, he will be playing again in a couple of days."