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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
oE. x.: elbow joint
Gliding joint → Also known as plane joint. Where one
smooth surface slides across another
oE. x.: wrist joint
Condyloid joint → allows movement without rotation
oE. 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: 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
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
Any
questions?