1. Skeletal System
Your skeletal system gives your body shape and support, provides protection for vital organs, and produces blood cells.

2. What does the skeletal system do?
Without the skeletal system we would be shapeless blobs on the floor
What is a skeleton?
A framework of bones that support the muscles and organs and protect the inner organs
Bones also serve as points to which the muscles attach and create body movement
Inside some bones, there is a soft tissue that makes new blood cells

3. How do bones grow?
At birth, the skeletal system is soft and mostly made of cartilage
As a child grows, bone tissue begins to replace the cartilage
At the end of long bones is a band of cartilage called the growth plate (epiphysis)
Cartilage that will be replaced by bone is grown here

4. http://kidshealth. org/PageManager. jsp

5. Your skeleton is made up of 206 bones and has two main parts, the axial skeleton and the appendicular skeleton. The image to the right shows some of the major bones.

6. Appendicular skeleton = made up of 126 bones that form the frame to which the muscles are attached and enable the body to move about
Axial skeleton = central bones that work together to provide support and protect vital organs

7. What are bones made up of?
Outside layer of a bone is made up of a membrane called the periosteum
Contains blood vessels that supply nutrients to the bone and nerves, which signal pain
Under the periosteum is a hard material called compact bone which provides support and is made up of living bone cells, minerals, protein fibers, blood vessels and nerves
Inside compact bone is a network of spongy bone which is a connective tissue that makes bones both light and strong
Many bones also contain a soft tissue called bone marrow which can be either yellow or red
Long bones are filled with yellow marrow which is mostly made of fat and stores energy
Other bones contain red bone marrow in which the production of blood cells begin

10. How are bones held together?
Muscles, tendons, and ligaments hold bones together
Two or more bones meet at places in the body called joints
Ligaments, which are tough bands of tissue, hold the ends of bones together at joints
Tendons are cords of connective tissue that attach muscles to bones.
Muscles and tendons attach to the bones on either side of a joint, holding the joint together tightly

12. OUCH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

13. Is it bad to crack knuckles?
No, the popping or cracking sound made by some joints is very normal
Pulling on the joint creates a vacuum inside the joint
This vacuum causes tiny air bubbles in the joint fluid to burst. The result is a “pop” or “crack” that you can hear.
Popping joints is not clearly linked with arthritis which is a painful inflammation of the joints

14. Do all joints move?
No, some joints are fixed, such as the ones between the bones in the skull
A fixed joint does not allow any movement
Other joints, such as semi movable joints (most of the vertebrae in the spine) allow only a small amount of movement

15. Ball and socket joint all major movement = hips and shoulders
Bones attached at the hinge joint can simply move back and forth (knees and elbows)
Movement in all ways except rotation! (Wrists and ankles)

16. Questions for you! What are the four basic parts of the bone?
Four layers
Periosteum = contains blood vessels that transport nutrients to the inner layers of the bone.
Compact bone = provides support
Spongy bone = makes bones light and strong
Bone marrow = yellow stores fat for energy and red is a site of blood cell production

17. Questions for you! How do most bones grow?
The structures that will become bones are initially made up of cartilage. New cartilage is produced as a child grows and increases bone size to mature length. Bone tissue replaces the cartilage as a person grows. Cartilage is retained at the ends of the longest bones in the body.

18. Questions for you! List 3 types of joints
Fixed joint, semimovable joint, hinge joint, ball and socket joint, pivot joint, and/or ellipsoidal joint

19. Question for you! Do you know what role bones play concerning calcium?
Calcium is part of teeth and bones and is used to regulate the function of the nerves and muscles. Sources = dark, leafy veggies, milk and dairy products and calcium fortified juices. If bone calcium becomes depleted, the bones become brittle and can fracture. 

20. Skeletal Assignment
Page 529 Questions 1-4
Due tomorrow!