Information
How do broken bones heal?
What is the largest/smallest bone in your body?
Can your students imagine themselves in a large pile on the floor not begin able to move? Well that is what would happen if they had no bones. Ask them if they have seen a baby or if they have a little brother or sister? Begin a discussion about their bones and ask them if theirs are the same size as yours or the same size as their dads, or even the same size as Shaquille O'Neal? Once the material is introduced, this activity will show students how their bones grow and how they heal!
You begin your life with over 300 bones and as you get older you have only 206. Most of your body is soft and rubbery. This rubbery cartilage stays that way so it is easier for you to be born. After you are a few months old, your bones grow. You grow very fast and your bones will begin to get hard so that you can start to walk and run. The once rubbery cartilages join with other pieces of cartilage and then turn into bones. Your bones grow and change because they are made of living cells. As you get older your bones may join together. The Greek meaning of the word skeleton is "dried up". We know this is not true. Bone is made of living tissue and minerals. So how do you grow if your bones are hard and do not stretch?
Ask the students if their mother tells them to eat their vegetables and drink their milk so you can grow big and strong? Well she is right! Bones are made up of a substance called minerals. These minerals contain calcium and phosphorus. This makes our bones hard. We need calcium and phosphorus everyday to keep our bones strong. Your bones are composed of layers. This layering makes your bones strong. Each layer has a specific function.
Bones are also made of a protein fiber called collagen. The protein holds the bone together so we can run and jump without breaking anything. Bones would crumble if the collagen was removed. Have you ever broken a bone? You know that it will eventually heal. The outer cover of your bone is covered with periosteum. This is a tough skin like cover that contains blood vessels and nerves. These blood vessels provide food and oxygen to your bones. This tough skin like cover helps your bones grow and repair from a break.
The first layer gives your bone strength and is so hard that a doctor would use a saw like instrument to cut through it. This layer is called compact bone. There are small holes in this area to allow blood vessels and nerves to pass. This compact bone area is dense. The next layer is area called the cancellous bone. The cancellous is sponge like in shape, but very hard. This sponge looking structure gives your bones extra support. In some bones, the inner cancellous region or center of the bone is the site of blood cell formation. This active blood forming region is called bone marrow. This spongy bone marrow is important because blood cells are made there. Red blood cells which carry oxygen throughout the body are produced in this area, along with white blood cells that fight disease and infection. Platelets are also produced in this area. These platelets clot the blood if you are injured. Yellow marrow is also stored in this area. Yellow marrow contains fat and releases it to different places in the body.
Over six million Americans break a bone each year. There are several types of fractures. An oblique fracture occurs across the bone in a diagonal way. A spiral fracture is when the fracture travels in a spiral shape around the bone. A transverse fracture is straight across the bone. Some of you may have heard of a compound fracture. This is when the broken bone pierces through the skin! A simple fracture is when the bone does not pierce the skin.
If you should break a bone, a doctor or orthopedic surgeon will x-ray the area to find where the fracture occurred, what kind of fracture and then cast it to keep it from moving. Once your broken bone is in a cast, your bone will begin to heal. This usually takes six to eight weeks. How does this happen? You learned that the bone is covered with a protective layer called periosteum. You also learned that blood cell and vessels are located in this area. Well your blood clots rush to this area, between the broken bones. After a few days, your bone cells from the periosteum join in and close up the area. Callus, which is new bone tissue, develops and after a while the broken bones begin to join. The callus then hardens and you are healed!
Many diseases also occur. One very dangerous disease is rickets. Rickets occurs when a person does not have enough calcium to keep their bones strong. The bones become soft and bend. Small children in countries were food is limited can be seen with very pronounced bends in the legs.
Now it is time to begin the activity with the students. Ask them to find their femur! Do they feel how long this bone is? It is the longest bone in your body. In the activity the students will make a bone. Have the students to www.ask.com and view pictures of a femur. This will give them a good idea on the shape of the bone.
Project: Let's Make a Bone
Objective: To show students bone size, structure and shape.
Materials: 1 paper towel tube, 1 cup flour, 5 cups water (1cup and 4cups separated), 1 large plastic bowl, newspaper cut into strips, masking tape, white, tan tempera paint, paint brush.
Procedure: Note- Teacher should prepare glue mixture at home or where there is access to a stove. Mix 1 cup flour into 1 cup water and set aside. Simmer to a slight boil the other 4 cups of water. Remove from stove and slowly stir in flour mixture. Let cool for 5 minutes or longer. Pour mixture into container to bring to classroom. Students will tear newspaper into strips about 1 inch wide. Once the strips are completed, the student will use larger pieces of newspaper and crumble into ball shape. Using tape, the student will attach the newspaper to the ends of the tube to form the shape of a femur using visual pictures supplied by the teacher or ones they printed from the computer. Once the proper shape has been formed, students will dip the 1 inch newspaper strips into the flour/glue mixture and wrap around the bone shape.
After a day or two the bone model will be dry. Students will use the paint and brush to complete the bone.
This model could be used not only as a visual representation of a bone but also for science experiments to see how much force or pressure can be placed on the bone before it breaks.
Let's Make a Bone Score Sheet
1.________pts Follows project directions
2.________pts Bone has shape similar to a bone in the human body
3.________pts Bone has support (doesn't fall apart)
4.________pts Student can orally state five facts about bone structure.
25 points per section
Grade:
100-90pts= A E/E-
89-80pts= B S+
79-70pts= C S-
69-60pts=D N
59-0pts=F N-
Vocabulary Words for Word Wall
Femur | stirrup | periosteum | compact bone
Marrow | calcium | phosphorus | transverse fracture
Callus | red blood cell | white blood cell | cancellous bone
Oblique fracture | Blood platelets | Spiral fracture