By Katherine Wang and Jennifer Cheng

1. The Skeletal System By Katherine Wang and Jennifer Cheng π

2. Background • provides support for the body • protects the internal organs and fragile body tissues.  • composed of all the bones in your body and other tissues (tendons, ligaments, and cartilage) • Has two parts, axial and appendicular

3. Functions of the skeletal system • Strength: gives shape to body • Protection of organs • Leverage for movement • Production of red blood cells

4. Parts of the Skeletal system • Axial skeleton • the main supportive structure of the body • Central section of the skeleton • Includes skull, vertebrae, sternum, and ribs • Appendicular skeleton • Freely movable parts of upper and lower limbs • Outer part of skeleton • Includes shoulders, hip bones, arms, wrists, hands, legs, and feet

5. The Bone • Is responsible for shape and form of human body • Made of cells and protein fibers surrounded by calcium salts • Stores important minerals such as calcium and phosphorus • Structure: • Outer layer of strong, dense, compact bone • Under outer layer is spongy bone, which is lighter than the top layer • Most bones have bone marrow in the middle • Yellow marrow is made of fat cells and stores fat • red marrow produces red and white blood cells and platelets

6. Growth of the bone • Osteoclasts: cells that break down old bones and replace the old bone with new bone tissue. This is called bone remodeling • Chondroblasts: cells that are responsible for forming new cartilage • When bones fracture, blood vessels in the bone also break. • Blood clots and forms a fracture hemotoma, which keeps the bone stable and stops the flow of blood • Cells in the bone then remove dead and damaged tissue, which causes swelling and inflammation • After a few days, the fracture hematoma becomes tougher, and turns into a soft callus • Fibroblasts then start to produce collagen, a type of fiber and the main protein in bones and connective tissues • Osteoblasts then produce new bone cells

7. Types of joints • Joints are the point of contact between two bones • Are classified by amount of movement • There are three types of joints • Immovable • Slightly movable • Freely movable • Joints can also be known as an articulation

8. Immovable joints • Joints where two or more bones are located close together but cannot move • E. x.: The skull • Synarthrosis→ The immovable joints between the bones of the skull

9. Slightly movable joints • Joints that are tightly connected but have limited movement • E. x.: back bone and hip bone Back bone

10. Freely movable joints • Do not have limited motion • 6 types of freely movable joints • Ball and socket joint → where the rounded head of a bone sits in the cup of another • Is able to move in all directions • E. x.: shoulder joint • Saddle joint → allows movement back and forth and side to side • Does not allow rotation • E. x.: the thumb • Hingle joint → where two bones open and close in a single direction • E. x.: the knee joint

11. Freely movable joints (cont.) • Pivot joint → where one bone swings around the ring formed by another bone • E. x.: elbow joint • Gliding joint → Also known as plane joint. Where one smooth surface slides across another • E. x.: wrist joint • Condyloid joint → allows movement without rotation • E. x.: jaw or finger joints

12. Freely movable joints (cont.)

13. Connective tissues and parts • Tendons: soft, elastic connective tissues that attach muscle to bone • Muscles move bones by pulling on tendons • Ligaments: tough tissue that connects bones to bones • Cartilage: stiff but flexible tissue that is found between joints • Allows joints to move against each other without pain • Synovial membrane: a thin membrane in freely moving joints that lines the joint capsule in fluid

14. Weaknesses/strengths of the skeletal system • Bones can heal themselves • Bones are very easily broken • 6.8 million Americans fracture of break a bone each year • Most people in the U.S. will break two bones in his or her lifetime

15. Types of fractures • Oblique fracture: when a bone breaks diagonally • Communited fracture: bone breaks into many pieces • Spiral fracture: break occurs in a line around the bone • Compound (open) fracture: broken bone sticks out of the skin • Greenstick fractures: bone breaks only on one side and does not break completely • Transverse fracture: break occurs in a straight line across the bone • Simple fracture: bone is only partially fractured

16. Diseases of the skeletal system • Osteoporosis: condition where your bones become weaker are likely to break. • treatment consists of eating calcium and vitamin D rich foods • Medicine is also needed • Paget’s Disease of Bone: disease where bones grow weaker and larger than normal, making it easier to break your bones • Symptoms are pain, enlarged or broken bones, and damage in the cartilage • Medicine and surgery is needed • Ewing’s Sarcoma: type of bone cancer in the bone marrow • Symptoms include extreme pain and swelling at site of tumor • Surgery, amputation, chemotherapy, and radiation are all used to cure it

17. How to maintain health of the skeletal system • Drink lots of milk: Milk contains a lot of calcium, which is good for your bones. Also take vitamin D and calcium supplements • Weight lifting exercises: weight lifting is essential to building strong bones and keep your bones healthy • Wear a helmet or other kinds of padding while playing sports. This prevents serious injury to bones

18. Fun facts • Our bones would be 6 times stronger than steel if both were the same weight • The smallest bone is the same size of a rice grain • Of the 206 bones in the skeletal system, 52 of them make up our feet

19. Thank you! Any questions?