Your Heart, Lungs, and Muscles: How Your Body Works Together
Right now, without you doing a single thing, your heart is beating. It beats about 100,000 times every single day — that is 40 million times every year! Your lungs are puffing in and out about 20,000 times today. Your muscles are holding you up, moving your eyes, and even helping you smile. These three amazing body parts work together like a team to keep you going.
What You'll Learn
In this lesson you will: - Learn what the heart does and how big it is - Find out how your lungs help you breathe - Discover how muscles move every part of your body - Understand how these three parts work as a team
Your Amazing Heart
Your heart is a muscle about the size of your fist. It sits in the middle of your chest, a little to the left. The heart's job is to pump blood all around your body — from the top of your head to the tips of your toes. Blood carries oxygen and food energy to every part of you. Imagine the heart as a pump at a water park: it pushes water (blood) through all the slides (blood vessels) so every rider (body part) gets what it needs.
Breathing with Your Lungs
You have two lungs inside your chest, one on each side of your heart. When you breathe IN, your lungs fill up with air — like two balloons getting bigger. Your body takes the oxygen out of that air and uses it for energy. When you breathe OUT, your lungs push out a gas called carbon dioxide. Your body made this gas while using energy and does not need it anymore. Your lungs and heart are best friends: the heart sends blood to the lungs to pick up fresh oxygen, then sends that oxygen-rich blood all over your body.
If you unfolded all the tiny air sacs in your lungs and spread them flat, they would cover a tennis court! That enormous surface area helps your body grab lots of oxygen with every single breath.
Muscles That Move You
You have more than 600 muscles in your body! Some muscles you control on purpose — like the ones in your arms when you wave, or your legs when you kick a ball. These are called voluntary muscles. Other muscles work all by themselves without you thinking about it — like the muscles in your stomach that help digest food. Your heart is also a muscle, and it never rests. All your muscles need oxygen from your blood to work, which is why your heart beats faster when you exercise — it is sending more oxygen to your hardworking muscles.
What does blood carry from the lungs to the rest of your body?
Why does your heart beat FASTER when you run?
Heartbeat Before and After
Find your pulse by gently pressing two fingers on the inside of your wrist just below your thumb. Count how many beats you feel in 15 seconds, then multiply by 4 — that is your beats per minute while resting. Write it down. Now do 30 jumping jacks and count again right away. Write that number too. Draw two big heart shapes on paper: label one 'Resting Heart' and the other 'Working Heart,' and write your numbers inside. In one sentence, explain why you think the numbers are different.
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