The Human Body
Grade 2 · Science · Study Guide
Your body is an amazing machine! Learn about the major body systems and how they keep you healthy and moving.
Your body is made up of many different systems that work together to keep you alive and healthy. The skeletal system is made of bones that give your body shape and protect your organs. The muscular system is made of muscles that help you move. Your bones and muscles work as a team — muscles pull on bones to make you walk, run, and jump!
The digestive system breaks down food into nutrients your body can use for energy. It starts in your mouth when you chew food, and continues through your stomach and intestines. The respiratory system brings oxygen into your body through your lungs when you breathe. Your heart pumps blood through your circulatory system, delivering oxygen and nutrients to every part of your body.
Taking care of your body is super important! Eating healthy foods, drinking water, getting exercise, and sleeping enough all help your body systems work their best. Your body works hard every second — even when you are sleeping!
| System | Main Parts | Main Job |
|---|---|---|
| Skeletal | Bones, joints | Support, protect organs, allow movement |
| Muscular | Muscles, tendons | Move the body |
| Digestive | Mouth, stomach, intestines | Break down food into nutrients |
| Respiratory | Nose, throat, lungs | Bring oxygen in, push carbon dioxide out |
| Circulatory | Heart, blood vessels, blood | Pump blood and deliver nutrients |
Key terms
- skeletal system
- The system of bones that gives your body its shape and protects organs
- muscular system
- The system of muscles that allows your body to move
- digestive system
- The system that breaks down food into nutrients the body can use
- respiratory system
- The system that brings oxygen into the body through the lungs
- circulatory system
- The system where the heart pumps blood throughout the body
- nutrient
- A substance in food that the body uses for energy and growth
Flashcards
- Skeletal system
- All of your bones; gives the body shape and protects organs
- Muscular system
- All of your muscles; allows you to move your body
- Digestive system
- Breaks food down into nutrients; includes mouth, stomach, intestines
- Respiratory system
- Brings oxygen into the body through the nose and lungs
- Circulatory system
- Heart and blood vessels that pump blood throughout the body
- Nutrient
- A substance from food that gives the body energy and helps it grow
Practice questions
Which body system is made of bones?
- Muscular system
- Digestive system
- Skeletal system
- Respiratory system
Show answer
Answer: Skeletal system
The skeletal system is made up of all your bones. It supports your body, protects organs, and works with muscles to allow movement.
The heart is the main organ of the circulatory system.
Show answer
Answer: True
The heart is the central organ of the circulatory system. It pumps blood through blood vessels to every cell in the body.
The system that breaks down food into nutrients is called the ___ system.
Show answer
Answer: digestive
The digestive system processes food — starting in the mouth and moving through the stomach and intestines — to extract nutrients.
Which system brings oxygen into your body?
- Skeletal system
- Respiratory system
- Muscular system
- Digestive system
Show answer
Answer: Respiratory system
The respiratory system uses your nose, throat, and lungs to take in oxygen from the air and release carbon dioxide.
Muscles and bones work together to help you move.
Show answer
Answer: True
Muscles attach to bones via tendons. When muscles contract, they pull bones and create movement.
Fun facts
- You have 206 bones in your body — but babies are born with about 270 bones that fuse together as they grow!
- Your heart beats about 100,000 times every single day without stopping!
- The small intestine in your digestive system is about 20 feet long — coiled up inside you!
Get a personalized course on The Human Body built around your child.