The Skeletal System

1. The Skeletal System Strong & Living, Structure of Bones, How Bones Form, Joints, Taking Care of Bones, Diagnosing Bone and Joint Injuries

2. Bones—Strong and Living • The word “skeleton” actually comes from a Greek word meaning “a dried body” but your bones are very much alive! • Bone Strength • Strong & lightweight • Can absorb more force without breaking than concrete • Only make up about 20% of your weight • Made of minerals like phosphorus and calcium. Basically, if you weighed 100 lbs, then your bones would make up 20 lbs and the leftover 80 would be muscle and fat.

3. Bones—Strong and Living continued! • Bone Growth • Bones are constantly creating new bone tissue as you grow • Bones absorb the force of your weight when you move, so new bone tissue is needed. • Bone tissue grows to fill in the gap between broken ends of the bone.

4. The Structure of Bones • All bones are covered in a tough outer membrane • This is where blood vessels enter and leave the bone • Beneath that is a layer of hard compact bone • Has small canals with blood vessels running through it.

5. The Structure of Bones continued! • Spongy bone is found at the ends of bones • Contains many small spaces • Keeps bones light • Marrow is found beneath compact bone and between spongy bone. • Two types of marrow: red and yellow • Red marrow produces red blood cells • Yellow marrow stores fat for energy

6. How Bones Form • Cartilage is a connective tissue that is more flexible than bone. • Also covers many ends of bones as a “cushion” for joints. • As an infant, you are born with more cartilage in your skeleton that is replaced with bone as you grow older. • By the time you stop growing, most cartilage has been replaced by bone. • However, the cartilage in your nose, ears, ribcage, and between your joints will never by replaced by bone.

7. How Bones Form Picture! 13-year-old 3-year-old 1-year-old

8. Joints of the Skeleton • Take a few seconds and talk to the students at your table about what life would be like if your femur ran from your hip to your ankle. • How would your life be different? • Luckily, our skeleton has joints. • A joint is a place in the body where two bones come together.

9. Joints of the Skeleton continued! • Our bodies have two kinds of joints • Immovable – a place where two bones meet that allows for little or no movement. • Movable– allows the body to make a wide range of movements. Bones are held together by strong connective tissue called ligaments.

10. More Joints! Gliding joint – allows one bone to slide over another. Found in wrists and ankles. Ball-and-socket joint– allows for the greatest range of movement. Found in shoulders and hips. Pivot joint– allows one bone to rotate around another. Found in the vertebrae in your neck. Hinge joint– allows extensive forward or backward motion. Found in your knees and elbows.

11. Taking Care of Your Bones • Keep your skeleton healthy by combining a balanced diet and regular exercise. • Your diet should include: • Calcium and phosphorus • Meats, grains, and leafy green vegetables • Also dairy products • Get plenty of exercise! • Walking, sports, skateboarding, aerobics, etc.

12. Taking Care of your Bones • As people get older, they begin to lose some minerals within their bones. • Osteoporosis is a condition in which body’s bones become weak and break easily. How can we prevent this?

13. Diagnosing Bone and Joint Injuries • Common skeletal injuries • Fracture – A break in a bone • Sprain – Occurs when ligaments are stretched too far and tear in places • Most common joint injury • Dislocation – Occurs when a bone comes out of its joint • Sometimes doctors can put the bone back in place • Sometimes individuals may need surgery An x-ray image of a broken bone.

14. X-Rays: A Look Inside the Body • X-rays are a form of energy that travels in waves • Helps us determine whether bones are broken • Because most x-rays pass through the skin and other body tissues, the X-rays strike the photographic film beneath the area. Unlike other body tissues, bone absorbs X-rays.

15. Magnetic Resonance Imaging • A new method was developed in 1970 that showed clear images of both bone and soft tissue. • Known as an MRI, the machine sends off magnetic energy that makes body molecules vibrate or resonate.