BY KATHERINE WANG AND JENNIFER CHENG The Skeletal System π

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

FUNCTIONS OF THE SKELETAL SYSTEM  Strength: gives shape to body  Protection of organs  Leverage for movement  Production of red blood cells

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

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

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

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

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

SLIGHTLY MOVABLE JOINTS  Joints that are tightly connected but have limited movement  E. x.: back bone and hip bone Back bone

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 o Is able to move in all directions o E. x.: shoulder joint  Saddle joint → allows movement back and forth and side to side o Does not allow rotation o E. x.: the thumb  Hingle joint → where two bones open and close in a single direction o E. x.: the knee joint

FREELY MOVABLE JOINTS (CONT.)  Pivot joint → where one bone swings around the ring formed by another bone o E. x.: elbow joint  Gliding joint → Also known as plane joint. Where one smooth surface slides across another o E. x.: wrist joint  Condyloid joint → allows movement without rotation o E. x.: jaw or finger joints

FREELY MOVABLE JOINTS (CONT.)

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

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

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

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

HOW TO MAINTAIN HEALTH OF THE SKELETAL SYSTEM  Drink lots of milk  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 exercises: weight lifting is essential to building strong bones and keep your bones healthy  Wear a helmet or other kinds of padding  Wear a helmet or other kinds of padding while playing sports. This prevents serious injury to bones

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

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