1. The Skeletal System

2. The Skeleton Supports the body, protects internal organs,
provides for movement,
stores mineral reserves,
provides site for blood cell formation

3. Structure of Bones
Bones are a solid network of living cells and protein fibers that are surrounded by deposits of calcium salts.
Periosteum = the tough layer of connective tissue that covers the bone
Blood vessels pass through it and carry oxygen and nutrients to the bone

4. Haversian canals = the network of tubes running through your bone that contains blood vessels and nerves.
Dense tissue called spongy bone is found inside the outer layer of compact bone.
Very strong not soft like name indicates
Lattice networking makes bones strong but not heavy

6. Bone marrow is the soft tissue within bones
There are two types of bone marrow
Yellow marrow – mainly fat cells
Red marrow – makes red blood cells, some white blood cells, and platelets

7. Development of Bones
Cartilage is a type of connective tissue that is made up of cells scattered in a network of protein fibers including tough collagen and flexible elastin.
The skeleton of an embryo is composed almost entirely of cartilage

8. Cartilage is replaced by bone during the process of bone formation called ossification
Ossification starts around 7 months before birth
In adults cartilage is found in flexible parts such as the tip of the nose and external ears.
Also found where ribs meet the sternum

9. Joints Joints are places where a bone meets another bone
Joints are classified based movement, immovable, slightly movable or freely moveable

10. Slightly movable joints permit a small amount of restricted movement
Immovable joints are sometimes called fixed joints because they allow no movement
Example: the bones in the skull
Slightly movable joints permit a small amount of restricted movement
Example: the two bones of the lower leg and adjacent vertebrae

11. Freely movable joints permit movement in one or more directions
Ball and socket
Hinge joint
Pivot joint
Saddle joint

12. Structure of Joints
In freely movable joints cartilage covers the surfaces to protect the bones as they move
There is also a joint capsule that has two layers
Ligaments are a layer of tough tissue that hold bones together
Synovial fluid allows bones to slide over each other smoothly

13. Skeletal system disorders
Inflammation is when increased fluid builds up causing swelling, redness, pain, and heat
Caused by strain on a joint
Arthritis is an inflammation of the joint itself
Osteoporosis is a weakening of the bones
More common in older people (especially women)