Body Systems and Senses — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. Blood vessels that carry blood away from the heart are called arteries.
Grade 4 science introduces arteries as the vessels that carry oxygen-rich blood from the heart.
2. Air enters the lungs through a tube called the windpipe.
Grade 4 students learn the windpipe (trachea) carries air from the throat into the lungs.
3. The long tube where most nutrients are absorbed from food is the small intestine.
Grade 4 science teaches the small intestine absorbs most nutrients from digested food.
4. Bones meet other bones at places called joints.
Grade 4 students learn joints let bones move and connect parts of the skeletal system.
5. Muscles move bones by contracting, or getting shorter and pulling.
Grade 4 science explains that muscles contract to pull on bones and produce movement.
6. The spinal cord is part of the nervous system and runs down the back inside the spine.
Grade 4 students learn the spinal cord carries nerve signals between the brain and the rest of the body.
7. Carbon dioxide leaves the body when we breathe out.
In Grade 4 science, the respiratory system removes carbon dioxide each time we breathe out.
8. The skull is part of the skeletal system and protects the brain.
Grade 4 students learn the skull is a bone that protects the brain from injury.
9. Blood that returns to the heart travels through vessels called veins.
Grade 4 science teaches that veins carry blood back to the heart to be pumped to the lungs again.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Skeletal system
→ Bones that support and protect the body
Bones that support and protect the body
Muscular system
→ Muscles that contract to move bones
Muscles that contract to move bones
Respiratory system
→ Lungs that take in oxygen and release carbon dioxide
Lungs that take in oxygen and release carbon dioxide
Nervous system
→ Brain and nerves that control body actions
Brain and nerves that control body actions
Grade 4 students should pair each major body system with its key organs and function.