The respiratory system is the group of tissues and organs in your body that allow you to breathe. This system includes your airways, your lungs, and the blood vessels and muscles attached to them that work together so you can breathe.
The respiratory system’s main function is to supply oxygen to all the parts of your body. It does this through breathing: inhaling oxygen-rich air and exhaling air filled with carbon dioxide, which is a waste gas.
This is how the respiratory system works:
First you breathe air in through your nose and mouth, which wets and warms the air so it won’t irritate your lungs.
Then the air travels through your voice box, down your trachea (windpipe), and though two bronchi (bronchial tubes) into your lungs. Cilia, tiny mucous-covered hairs, in your airways trap foreign particles and germs to filter the air that you breathe. You then cough or sneeze the particles out of your body.
The diaphragm, abdominal muscles, and other muscles help your lungs expand and contract so you can inhale and exhale.
When you inhale, the air goes through the bronchi in your lungs to blood vessels that connect to veins and arteries. These veins and arteries carry the blood throughout your body.
When you exhale, the carbon dioxide goes out the same way, exiting your body through your nose and mouth. If you can’t breathe or can’t breathe well, your body won’t receive enough oxygen to keep it running, and it will also be poisoned by the carbon dioxide that is building up in your blood with nowhere to go.
Fun Fact: You breathe in and out anywhere from 15 to 25 times per minute!
My Lungs My lungs help my body breathe. The upper part of my chest is almost filled with my lungs. My lungs are made up of millions of elastic-like sacs which fill up with air and let out air. My lungs can hold about as much air as a basketball! Air comes into my body through my nose and mouth. It travels down my trachea (windpipe), through my bronchial tubes, and then to both my lungs. My lungs trade air with my blood. My heart pumps used blood to my lungs. My lungs take the carbon dioxide and other things I can’t use out of my blood. My lungs give back fresh oxygen to my blood. After the trading is done, my blood goes back to my heart to work again. A big, strong muscle helps make my lungs work. It is called my diaphragm. My diaphragm is under my lungs. It helps my lungs expand when they are filling up with air. My diaphragm also helps my lungs squeeze out the used air. So, every time I inhale (breathe air in) and every time I exhale (breathe air out), I know my lungs are working. My lungs help my body breathe. They are like balloons filling up with air and letting air out!
THE CIRCULATORY SYSTEM
Did You Know?
• The body of an adult contains over 60,000 miles of blood vessels!
• Your heart beats some 30 million times a year!
• A “heartbeat” is really the sound of the valves in the heart closing as they push blood through its chambers.
What is it?
It’s a big name for one of the most important systems in the body. Made up of the heart, blood and blood vessels, the circulatory system is your body’s delivery system. Blood moving from the heart, delivers oxygen and nutrients to every part of the body. On the return trip, the blood picks up waste products so that your body can get rid of them.
Your Heart
About the size of your clenched fist, your heart is a muscle. It contracts and relaxes some 70 or so times a minute at rest — more if you are exercising — and squeezes and pumps blood through its chambers to all parts of the body. And it does this through an extraordinary collection of blood vessels.
Your Blood Stream
Your blood travels through a rubbery pipeline with many branches, both big and small. Strung together end to end, your blood vessels could circle the globe 2 1/2 times! The tubes that carry blood away from your heart are called arteries. They’re hoses that carry blood pumped under high pressure to smaller and smaller branched tubes called capillaries. The tubes that more gently drain back to the heart are veins.
How does your blood get oxygen?
When you inhale, you breathe in air and send it down to your lungs. Blood is pumped from the heart to your lungs, where oxygen from the air you’ve breathed in gets mixed with it. That oxygen-rich blood then travels back to the heart where it is pumped through arteries and capillaries to the whole body, delivering oxygen to all the cells in the body — including bones, skin and other organs. Veins then carry the oxygen-depleted (has less oxygen now) blood back to the heart for another ride.
What’s blood, anyway?
Most of your blood is a colorless liquid called plasma. Red blood cells make the blood look red and deliver oxygen to the cells in the body and carry back waste gases in exchange. White blood cells are part of your body’s defense against disease. Some attack and kill germs by gobbling them up; others by manufacturing chemical warfare agents that attack. Platelets are other cells that help your body repair itself after injury.
My Heart
My heart is a strong pump that moves blood through my body. It
hangs in the center of my chest and is about the size of my fist.
My heart works all the time, even when I am sleeping. It pumps
blood that is full of oxygen and food through tubes called arteries.
This fresh blood travels to all my cells and feeds them. My blood
also cleans my cells. My cells give the blood carbon dioxide and
other things they can’t use. Then, my blood moves back to the heart
through tubes called veins.
My heart pumps this used blood to my lungs. My lungs take out the
carbon dioxide and put in new, fresh oxygen. Then, my blood goes
back to my heart to work again.
It takes about one minute for my heart to circle blood around my
body and back again. This is called circulation.
I can hear my heart working all the time. The beating sound my
heart makes is caused by the opening and closing of the valves inside
my heart. These valves are like doors. They let the blood in and out
of my heart.
So when I hear or feel my heart beating, I know my blood is circling
all around my body. My heart moves the blood to clean and feed
my cells.
