BONES

The Skeleton -Contains approx. 206 bones. -Main function: rigid framework for support, protection, and storage. -The human skeleton is divided into two parts: 1. axial (skull, ribs, spine, sternum) 2. appendicular (everything else)

Bone Structure Bone Marrow --- Red and Yellow Red Marrow --- Produces red blood cells & certain types of white blood cells. Red Marrow --- Produces red blood cells & certain types of white blood cells. Yellow Marrow --- Consists of fat cells & serves as energy storage. Yellow Marrow --- Consists of fat cells & serves as energy storage.

Bones Continued Periosteum --- Membrane that contains a network of blood vessels which supplies nutrients. (Outer layer of the bone.) Compact bone --- Allows the bone to endure a large amount of stress it receives upon impact. Spongy Bone - Network of connective tissue.

Bone develops from cartilage. Cartilage is a tough, flexible connective tissue. Cartilage will eventually harden during fetal development in a process called ossification.

Joints Joints are places where two bones meet. Joints are held together by ligaments, tough bands of connective tissue. Bursae help to absorb shock & keep bones from rubbing against each other. Tendons attach muscle to bones.

Hinge Joint  Found in your elbow. Allows you to move arm forward & backward. Like a door.

Gliding Joint  Allows bones to slide over one another. Example are the joints between the small bones of your feet. Allows your foot to flex when you walk.

Pivot Joint  Forms the top 2 vertebrae in your neck. Allows you to move your head side to side. (Saying “no”).

Ball & Socket Joint  Found in your shoulder or hip. Allows you to move your arm up & down, forward & backward, & rotate in a complete circle.

Saddle Joint  Found at the base of each thumb, allows you to rotate your thumbs and helps you grasp objects with your hand.