Notes- The Skeletal System

Functions

I. 5 functions of the skeletal system

A. Gives shape and support to your body.

B. Bones protect internal organs

1. The rib cage, sternum, and vertebrae protect the heart and lungs.

2. The cranium protects the brain.

C. Major muscles attached to bones.

Functions

D. Blood cells are formed in the red marrow of some bones.

E. Major amounts of calcium and phosphorus are stored. These elements make bones hard.

Notice the red marrow and the compact bone

Parts of bones

II. Parts of bones

A. 206- 214 bones in your body.

B. Classified by their shape.

(long, flat and short)

Parts of bones

C. Parts

1. Periosteum

a. Tough, tight – fitting

on the outside of the bone.

b. Small blood vessels carry nutrients into bone.

c. Also important in growth and repair of bone

Parts of bones

2. Compact bone a. Contains bone cells,

blood vessels, calcium, phosphorus, elastic fibers

b. Elastic fibers keep bones from being too rigid, brittle, or easily broken

Disorders

c. Rickets and Osteoporosis

are two disorders caused by lack of minerals

Rickets

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Osteoporosis

Parts of bones

3. Spongy bone

a. Found towards the end of long bones

b. Has lots of open spaces which cause bone to be light weight.

4. Marrow Cavity

a. In center of long bones

b. Filled with fatty tissue called marrow

1. Produces 2-3 million red blood cells per second

2. Produces white blood cells also

Parts of bones

5. Cartilage

a. Thick , smooth layer over bone’s ends

b. No blood vessels or minerals

c. Flexible, absorbs shock, makes movement easier

Bone Development

III. Bone Development

A. Before birth, our skeleton is cartilage

Bone Development

B. Osteoblast (bone- forming cells) replace cartilage.

C. Osteoclast break down bone and release calcium and phosphorus into your bloodstream. The blue arrows indicate the

osteoblasts. The yellow arrows indicate the bone matrix they’ve just secreted.

Fractures

IV. Fractures

A. Break in a bone

Fractures

B. Types of fractures

1. Simple : The bone has broken but the ends do not break through the skin.

2. Compound: Broken ends of bone stick out through the skin.

Name the Fracture

What kind of fracture is this?

It’s kind of tough to tell, but this is a _ _ _ _ _ _ fracture.

Joints

V. JointsA. Place where two or more bone meet.B. Ligaments- tough band of tissue that holds bones

together at jointsC. Types of joints1. Immovable a. Allows little or no movementb. Examples: pelvis and skull2. Movablea. Allows body to make a wide range of movements

Joints

b. Types

1. Pivot – head and arm (elbow)

2. Ball and socket- hip and shoulder

3. Hinge- knee, arm and fingers (conyloid)

4. Gliding- wrist, ankle and vetebrae

5. Immovable / Fixed joint – skull (cranium)

Static. How stuffworks.com

Hinge joint and pivot joint

Know the parts of a skeleton

Frontal View

Posterior View