Bones
Background Information & Activities

Bones are a kind of hard endoskeletal connective tissue that is found in all vertebrates. Bones give bodies their structure and protect internal organs. Muscles are attached to bone and they expand and contract to allow movement. The adult human body has 206 bones; the smallest is the stirrup, which is inside the ear. It is less than an inch long. Children are born with 300 bones--some consist of hard connective tissue and others are made of cartilage. Over time, the cartilage hardens and turns to bone and some bones fuse together. This accounts for the larger number of bones in children than in adults. This is also why younger children tend to fracture more bones than adults—young bones are more flexible. Furthermore, children are more inclined than adults to take risks with their bodies and break bones.

Bones are made up of three layers. The outermost layer is called the periosteum. It is a thin membrane that covers the bone and contains nerves and blood vessels to nourish the bone. Bones can grow and change and need oxygen and nutrients just like the rest of the body. The next layer is called compact bone. This is smooth and very hard. Under the compact bone are many layers of cancellous bone. Cancellous bone is spongy and not quite as hard as compact bone. These layers make bones light but strong. In the middle of the bone is marrow, which produces two kinds of stem cells. Hematopoietic stem cells produce blood cells (white blood cells, red blood cells, and platelets) and stromal stem cells produce fat, cartilage, and bone.

There are many bones in the human body, and your children should be able to identify the major bones. The skull is a set of 29 bones in the head that protects the brain. The ribcage includes the ribs and sternum and together they protect the heart and lungs. The spine is a set of vertebrae and cartilage along the back that hold the body up. It goes from the pelvis all the way up to the neck and the base of the head. Joints are places where bones meet. Some joints allow for a wide range of movement, such as the joints in elbow and knees, and other joints are rigid. Though some joints contain cartilage and are not technically considered bones, other joints begin as cartilage and grow into bone, such as the rigid joints in the cranium.

Bones can break, but they can also heal. As soon as a bone breaks, the body begins developing tissue to heal the bone. At first the tissue is soft, but over time it turns into hard bone. Doctors will apply a cast to some broken bones in order to stabilize the body and allow for proper healing. For serious fractures, in which bones are broken into a few or many pieces, doctors can insert steel rods to support the broken bones or in some cases, amputate.

Discuss bone health with your children. How can they care for their bones? They can use helmets, knee pads, elbow pads, and wrist guards when riding bikes, skating, or skateboarding. Following rules is also an important part of staying safe and making sure they don’t harm others. Calcium helps build bones, maintain them, and make them strong. Encourage your children to eat calcium-rich food, especially now as they grow and change, such as milk, cheese, yogurt, and dark leafy greens. Vitamin D helps the body absorb calcium, which is usually found in dairy products and children’s vitamins. The body also converts sunshine into vitamin D. Regular exercise is vital to keep bones healthy. Strong bones as a child will help prevent osteoporosis and other bone diseases later in life.

Bones Teacher Activities – Click Here!

Bones Family Activities – Click Here!

Bones Teacher Activities

Make a Skeleton

Divide the class into small groups or pairs and have students trace an outline of their bodies. Then discuss different bones in the body. Where is the bone found in the body? What does it do? Have students paint or draw their own bones in the outline. Then post their outlines around the classroom. As they grow and change, have students measure themselves against their own drawings. Encourage them to think about how their bones also grow and change.

Natural History Museum

The best way to learn about bones is to look at them. If possible, take a class trip to a natural history museum. Look at different dinosaur and animal bones and compare and contrast them. What bones do all vertebrates have? What bones do some animals have that humans do not? Encourage students to compare skulls of different animals and the sizes of spines and ribcages.

Talk to a Doctor

Invite a doctor to talk to your class. Before he or she arrives, brainstorm a list of questions to ask with the class. What do they want to learn about bones? Ask the doctor if he or she could bring in real bones or models of them. Many doctors have or have access to bones, models of bones, or even a full human skeleton. Have your doctor discuss the different parts and functions of bones and how to maintain strong, healthy bones. After the interview, have students make up posters encouraging good bone health. If possible, students can make a public service announcement about the importance of safety or a calcium-rich diet.

Bones Family Activities

Calcium Plan

For children 4-8 years old, the FDA recommends eating 1-2 cups of milk or other calcium-rich food a day. For girls and boys ages 9-13, the FDA recommends eating 3 cups. Calcium-rich foods include yogurt (preferably sugar free and low- or fat-free), cheese, tofu, calcium-fortified 100% orange juice, and dark leafy green vegetables like collard greens or spinach. Create a meal plan with your child to consume enough calcium in his or her diet. Going grocery shopping with your child will allow him or her to make her own food choices and feel excited about eating healthy.

Growth Chart

Start a growth chart for your child. Every month, measure your child and track his or her growing process. Ask your child to think about how his or her body has changed. Can they run farther or faster? Can they reach things they couldn’t reach before? Explain that as they grow, their bones grow and their muscles grow too.

Safety Checklist

Breaking bones can be painful and have serious health effects. Luckily, most accidents can be prevented. Together with your child, make a list of his or her favorite activities, such as bike-riding, skating, or cooking. Talk about the ways your child can be safe doing each activity. Create a checklist of safety tips for each activity. For example, for skating your checklist might include, helmet, knee pads, elbow pads, and wrist guards. Thick pants and thick socks are also important safety elements. Also write a few rules your child should follow, such as stopping at red lights and stop signs, slowing down through intersections, and outlining routes that are safe from speeding cars. Post the checklist by the door or by their gear so your child will be reminded about being safe.