Class I, II, and III – based on efficiency.

See Holt, Page 87

b. Classes of levers

RF

Class I

FR

Class II

FR

Class III

(Reading pp 157-160)

B. Bone Development.

Bone formation = Ossification.

Intramembranous and Endochondral

See – Lab 3 section “ossification”

Two types

(Reading page 189)

C. Injuries and disease.

1. The knee joint.a. anterior cruciateb. posterior cruciatec. lateral collaterald. medial collateral

2. Dislocation = tearing of ligaments that keep bones in place (bone is forced out of position.)

3. Sprain = Damage to ligaments. (tearing or straining tendons or ligaments)

4. Fracturesa. compound - bone sticks out through the skinb. simple - bone doesn't stick out through the skin

Metatarsal fracture

Clavicle Fracture

18 year old girl

12 year old boy

12 year old girl with buckle fracture of radius

5. Arthritis a. rheumatoid arthritis - inflammation of synovial membrane - articular hyaline cartilage destroyed

6. Rickets - from deficiency of vitamin D preventing ossification. The bones actually bend because cartilage still dominates. Vitamin D is needed for calcium and phosphorus absorption.

What are the functions of the skeleton?

Summary:

1) framework for support

2) attachment of skeletal muscles for movement

3) protection of vital organs

4) bone marrow is site of blood cell formation

5) bone stores minerals needed for metabolism