1 The Skeletal System Chapter 15

2 FIVE JOBS OF THE SKELETAL SYSTEM 1. Provides shape and support 2. Enables you to move 3. Produces blood cells 4. Stores materials for later use 5. Protects internal organs

3 BONE STRUCTURE Turn to page 473 Let’s read together… Why do we need spongy bone? What are the two types of marrow and what do they do?

4 BONE STRUCTURE Why do we need spongy bone? Spongy bone provides most of the strength and support for a bone because it is able to absorb shock easily. What are the two types of marrow and what do they do? Red marrow produces both red and white blood cells. Yellow marrow stores fat.

5 BONE GROWTH By yourself, read about bone growth and answer the questions… What is cartilage? What happens to cartilage as you grow? Why do you think it is necessary for a baby to be mostly cartilage?

6 BONE GROWTH What is cartilage? Cartilage is a flexible tissue. What happens to cartilage as you grow? Cartilage is replaced by bone throughout your life. Cartilage allows for growth plates to develop. Some cartilage is never replaced by bone. Why do you think it is necessary for a baby to be mostly cartilage? The baby’s bones would break during childbirth and the cartilage growth plate allows the baby to grow throughout its lifetime.

7 BONES AND JOINTS Chapter 15, section 2

8 JOINTS 2 TYPES OF JOINTS Fixed = can’t move, like those in your skull Movable = allow body to move Joint = a place where two bones come together allowing the body to move in different ways

9 LOOK AT YOUR JOINTS Under each picture, label which type of joint it is: Ball and Socket Hinge PivotGliding (hip) (elbow) (neck)(spine)

10 4 TYPES OF MOVABLE JOINTS 1. Ball and Socket = allow greatest range of motion- circular (shoulder and hip) 2. Hinge = extensive backward and forward motion (knee and elbow) 3. Pivot = one bone can rotate around another (neck) 4. Gliding = one bone can slide over another (wrist, ankle, spine)

11 THE STRUCTURE OF JOINTS Joints are under a great deal of stress. Joints are held together by ligaments, if they are stretched too far or torn it is called a sprain. Joints and bones are also cushioned by cartilage. Arthritis is a disease that causes joints to stiffen or swell.

12 KEEPING BONES HEALTHY Eat a well balanced diet with lots of calcium and phosphorous to keep bone strong Exercise helps bones grow stronger and denser Do this and avoid osteoporosis later in life (bones getting weak and break easily)

13 EXERCISES TO KEEP BONES HEALTHY Running Dancing Jumping jacks Speed walking Aerobics Boxing Any exercise where you force your bones to absorb the weight of your body. This prompts the cells to make new bone cells.

14 FOODS TO MAKE YOUR BONES HEALTHY Cheese Yogurt Lowfat ice cream Leafy green vegetables Calcium fortified cereals Calcium fortified orange juice Milk Whole grains

15 THE SKELETAL SYSTEM Cut and arrange your skeleton onto your paper. Double check the layout before gluing it on!

16 JOINTS Joint = a place where two bones come together allowing the body to move in different ways On your skeleton, color where you think you’d find joints

17 LOOK AT YOUR JOINTS Under each picture, label which type of joint it is: Ball and Socket Hinge PivotGliding (hip) (elbow) (neck)(spine)