1. The Skeletal System
Chapter 14
Section 2

2. Key Concepts no cares about
What are the functions of the skeleton?
What role do joints play in the body?
What are the characteristics of bone, and how can you keep your bones strong and healthy?

3. Vocabulary Skeleton Vertebrae Joint Ligament Cartilage Compact bone
Spongy bone
Marrow
Osteoporosis

4. What the Skeletal System Does
Can a building stand without a frame?

5. Five major skeletal functions
Just as a building cannot stand without frame you would collapse without your skeleton
Functions
Provides shape and support
Enable you to move
Protects your organs
Produces blood cells
Stores mineral and other materials until your body needs them

6. Shape and Support
The skeleton provides a framework that supports and protects many other body parts
The backbone or vertebral column is the center of the skeleton
The bones in the skeleton are in some way connected to this column
You can feel 26 small bones if your move your fingers down the center of your back
Bend forward at the waist and feel the bones adjust as you move
Think of each individual vertebra as a bead on a string it is flexible and able to bend

7. Production and Storage of Substances
Some of your bones produce substances that your body needs
The long bones of your arms and legs can be thought of as factories that make certain blood cells
Bones also store minerals such as calcium and phosphorus
When the body needs these minerals the bones release small amounts of them into the blood

8. Joints of the Skeleton
Joints allow bones to move in different ways as they are the place in the body where two bones come together
There are two kinds of joints
Movable and immovable joints

9. Immovable Movable Joints
Some joints in the body connect bones in a way that allows little or no movement
Bones of the skull are held together by immovable joints
Most joints in the body are movable they allow the body to make a wide range of movements
Movable joints are held together by connective tissues called ligaments
They also have a second type of connective tissue called cartilage which is more flexible than bone

10. Movable joints Hinge Joint-allows forward or backward motion
Your knee is a hinge joint as well as your elbow

11. Ball and Socket Joint Allows the greatest range of motion
The ball and socket joint in your shoulder allows you to swing your arm freely in a circle
Hips also have ball and socket joints

12. Pivot Joint Allows one bone to rotate around another
Pivot joint in your neck allows you to turn your head from side to side

13. Gliding Joint Allows one bone to slide over another
Your wrist or ankle enables you to bend and flex as well as make limited side to side motions

14. Cartilage
Covers the ends of the bones and keeps them from rubbing against each other

15. Bones-Strong and Living
Bones are complex living structures that undergo growth and developments

16. Bone Structure (1)
Femur is the body’s longest bone and connects the pelvic bones to the lower leg bones
A thin tough membrane covers all of the bone except the ends
Blood vessels and nerves enter and leave the bone through the membrane
Beneath the bones outer membrane is a layer of compact bone which is hard and dense but not solid

17. Bone Structure (2) Small canals run through the compact bone
These canals carry blood vessels and nerves from the bone’s surface to the living cells within the bone
Just inside the compact bone is a layer of spongy bone

18. Spongy Bone Like a SPONGE, spongy bone has many small spaces within it
This spongy structure makes spongy bone tissue lightweight but strong
It is also found at the ends of the bone
Spaces in the bones contain a soft connective tissue called marrow

19. Two types of Marrow Red and Yellow
Red bone marrow produces some of the body’s blood cells
As a child most of your bones contain red bone marrow
As a teenager only the ends of your femurs, skull, hip and breastbone contain red marrow
Other bones contain yellow marrow
This marrow stores fat that can serve as an energy reserve

20. Bone Strength
The structure of bone makes it both strong and lightweight
They are so strong they absorb more force without breaking than can concrete or granite rock
Bones are hard because they contain minerals-phosphorus and calcium
You can jump up and down or turn cartwheels without breaking bones

21. Bone Development The tip of your nose contains cartilage
As an infant much of your skeleton was cartilage
Over time the cartilage is replaced with hard bone tissue
This replacement of cartilage by bone tissue usually is complete by the time you stop growing

22. Bone Growth
Bones are alive-they contain cells and tissues such as blood and nerves
They also form new bone tissue as you grow as they are alive
Even after you are grown however, bone tissue continues to form within your bones

23. Taking care of your bones
A combination of a balanced diet and regular exercise are important for a lifetime of healthy bones
Diet and exercise are some ways of taking care of your bones

24. Osteoporosis
As people become older their bones begin to lose some of the minerals they contain
Mineral loss can lead to osteoporosis a condition in which the body’s bones become weak and break easily
It is more common in women than men

25. 1. What are five functions of the skeleton?
Provide shape and support
Enable you to move
Protect your organs
Produce blood cells
Store minerals and other materials

26. 2. What are four types of movable joints?
Hinge
Ball and socket
Pivot
gliding

27. 3. What are three types of tissue in bone?
Compact bone
Spongy bone
Marrow

28. 4. Which function of the skeletal system gives you a clue that bones are not dead or solid?
Bones make certain blood cells and release small amounts of minerals into the blood when needed.

29. 5. Where is marrow produced?
In the spaces in bone

30. 6. Does new bone tissue stop forming after you stop growing?
No, bones make new tissue when they absorb the force of your weight and when a bone has broken

31. 7. What do ligaments do?
They hold together the bones in movable joints.

32. 8. What substance keeps bones from rubbing against each other?
cartilage

33. 9. What other functions does the skeletal system perform besides providing support and protection?
Produces certain blood cells
Stores minerals

34. 10. Why are vertebrae important?
The are the bones that make up your backbone, and all other bones are connected to the backbone.