Our bodies do tons of different things every single minute of our lives to keep our bodies healthy and working the right way. In this post, we’ll talk about the structure of the human body in a way that both kids and adults will enjoy. We’ll talk about the main body systems: the musculoskeletal system, the cardiovascular system, the digestive system and the nervous system for kids.
The muscle and skeletal system for kids
All of the bones in your body make up the skeletal system, and the muscles you use to move different parts of your body make up the muscular system. Together, they give your body its shape and structure. You have more than 200 bones in your body, from big bones like the femur in your thigh, to tiny bones in your fingers. Bones do more than just support your body – they also have a substance called marrow inside them which is where your blood cells come from!
Your muscles are what allow you to walk, jump, swim and even write your name. Muscles do a lot of work all day long, so they are specially designed to be good at using energy you give you body through food.
The musculoskeletal system also includes joints, ligaments and tendons. Anywhere you can bend or twist a body part, you have a joint, which is a flexible cushion between two bones. You have joints in your knees, shoulders, fingers and even between every vertebra (back bone) in your spine! Ligaments are made of strong material that attaches bones to other bones, and tendons are what attach your muscles to your bones so they stay in the right place when you move around.
The cardiovascular system for kids
Every cell in every part of your body needs oxygen from the air you breathe, but how does it get there? Your cardiovascular system! The cardiovascular system includes the heart and all of the blood vessels in your body, which transport oxygen from your lungs to all the other parts of your body. Just like roads have different lanes for cars going in different directions, your body has different blood vessels for blood that has enough oxygen and blood has run out of oxygen and needs more.
Blood vessels that have blood that needs more oxygen flow to the heart. The heart then pumps that blood into the lungs so that they can get oxygen in exchange for carbon dioxide (the gas you exhale when you breathe out). Once the blood is full of oxygen, it gets pumped back to the heart through a different “road”. The heart can now take this blood and send it to all the parts of the body that need oxygen.
Your cardiovascular system is like the delivery service for your whole body. It carries oxygen and nutrients from the foods you eat all around your body.
The digestive system for kids
All the cells in your body need certain nutrients and energy, which they get from the food you eat. But before your body’s cells can do anything with your lunch, it first has to be digested by your digestive system. Your digestive system includes every part of your body that your food passes through: your mouth, throat, stomach, intestines, and anus (where your poop comes out).
Food needs lots of steps to be broken down and digested. The first step happens in your mouth while you chew your food. Your teeth break the food into small pieces, and mixes with the saliva (spit) in your mouth. When you swallow a bite, it goes down into the esophagus (throat) and into your stomach. Your stomach contains a strong acid which helps dissolve your food into tiny pieces. This acid would hurt the rest of your body though, so the digested food has to mix with another substance called bile to get rid of the acid.
When the acid is gone, the digested food moves into your small intestine. Even though we call it the “small” intestine, it’s actually about 20 feet long! It’s a long, thin tube that absorbs nutrients from your food as it moves through the tube. After a long journey through the thin “small” intestine, the food goes into the large intestine or colon, which is shorter but very thick. This is the last chance for your body to absorb what it wants from your food: proteins, sugars, vitamins and minerals, water, etc. Anything that is left over is material that can’t be broken down by the body, and this is what your poop is made of. This waste leaves the large intestine and goes into the toilet when you go to the bathroom.
The nervous system for kids
The nervous system is kind of like a super computer that tells every other part of your body what to do and when to do it. The main part of the computer is your brain, which has lots of different sections that have different jobs. The different areas of the brain “talk” to each other by sending electrical signals or sometimes special chemicals called neurotransmitters.
Your brain also has to communicate to the other parts of your body, everything from your heart and lungs to your fingertips and eyelids! This is done through special cells called nerves, which are actually a type of brain cell that can be very, very long. Your body has two different types of nerves. The first type allows you to sense things with your five senses: sight, hearing, touch, taste and smell. These nerves send a message to the brain so that you can sense these things. The second type of nerve is how your brain tells a certain body part to move. If you decide you want to stand up, your brain uses these nerves to tell your leg muscles to stand up.
Aside from making your body do the things you want it to do, your nervous system also controls things that you don’t have to pay attention to, like your heart beating or breathing.