1. Objectives 32.1 The Skeletal System
-List the structures and functions of the skeletal system.
-Describe the structure of a typical bone.
-List the different kinds of joints and describe the range of motion of each.

2. The Skeleton
The skeleton supports the body, protects internal organs, assists movement, stores minerals and is a site of blood cell formation.
There are 206 bones in the adult human skeleton.

3. 2 divisions of the Skeletal System include: Axial Skeleton
Appendicular Skeleton .

4. Axial Skeleton
The axial skeleton consists of the skull, the vertebral column and the rib cage.

5. Appendicular Skeleton
The bones of the arms and legs, pelvic and shoulder girdle form the appendicular skeleton.

6. Bones
Most of the mass of bone is mineral salts—mainly calcium and phosphorus.
However, bones are living tissue.

7. Structure of Bones
 The bone is surrounded by a tough layer of connective tissue called periosteum.

8. Structure of Bones
Beneath the periosteum is a thick layer of compact bone.

9. Structure of Bones
Nerves and blood vessels run through compact bone in channels called Haversian canals.

10. Structure of Bones
A less dense tissue known as spongy bone may be found under the outer layer of compact bone.

11. Bone Marrow
There are two types of bone marrow yellow marrow and red marrow.
1. Yellow Marrow – fat storage
2. Red Marrow – blood cell formation

12. Development of Bones
The skeleton of a human embryo is composed almost entirely of a type of connective tissue called cartilage.
Cartilage is gradually replaced by bone during the process of bone formation called ossification.

13. Development of Bones Bone tissue forms using cells called osteoblasts.
Mature bone contains osteocytes, which help to maintain and strengthen the bone tissue.

14. Joints
A place where one or more bones meet another bone is called a joint.

15. Types of Joints
Depending on its range of movement, a joint is classified as immovable, slightly movable or freely movable.
Immovable joints allow no movement.
Slightly movable joints permit a small amount of movement.
Freely movable joints permit movement in two or more directions.

16. Ligaments
Bones are held together at a joint by ligaments.