The Musculo-Skeletal System

Why Both? This system includes both skeletal and muscular systems because they need each other to function properly

The Skeletal System The skeleton is important because: It supports our body It stores minerals It allows us to move It protects our internal organs It makes blood cells

What are bones? Bones are living tissue Inside bones is a soft tissue called marrow New blood cells made by the marrow inside Contain nerve endings (sense pain) Lightweight and strong

Types of Bones There are two types of bones: compact and spongy Compact Bone: hard outer layer of bones gives bones their smooth, white, and solid appearance accounts for 80% of the total bone mass of an adult skeleton.

Types of Bone Spongy Bone Made up of compounds that make the bone lightweight Allows room for blood vessels and marrow

Groups of Bones Bones are divided into groups Flat Long Short Irregular

Groups of Bones Flat The purpose of flat bones is to protect important organs and to provide a flat surface muscle attachment. Include: the cranium (skull), scapula (shoulder blade), sternum (breast bone), pelvis, ribs and hip bone

Types of Bones Long The bone is longer than it is wide (that’s how it is classified) Growth plates at the end that are covered with cartilage Include: femur, tibia and humerus

Types of Bones Short Bones that are as wide as they are long Provide stability and support Do not move a lot Carpals and Tarsals (bones in wrists and feet)

Types of Bones Irregular Have their own category because they do not have distinct shape Include bones in your jaw and vertebrae (backbone)

Cartilage Tough and flexible Found in the nose, outer ear and joints Prevents cushioning and stops bones from rubbing together Minerals added to cartilage makes bone

Tendons A tough band connective tissue that connects muscle to bone Can only exert a pulling force When a muscle moves, the tendon pulls and moves the bone

Ligaments Tissue that connects bones to other bones to form a joint (like elastic bands) Prevents bones from moving at a joint and are important in preventing dislocation

Joints Are the points of our skeleton where two bones meet Every joint contains cartilage, tendons and ligaments Cartilage coats the ends of the bones Ligaments attaches two bones together Tendons attach muscles to the bones

Types of Joints There are 3 types of joints Fixed – does not allow movement Partially Movable – allows a little movement Movable – allows complete movement

Partially Movable Joints Allows a very little movement by the bones Ex. The joints between our vertebrae

Fixed Joints The bones are tightly locked together so no movement occurs Ex. Joints found in the skull

Movable Joints Ball and Socket – allows movement in almost all directions. One rounded end of the bone fits into the socket end of another bone Ex. Hips and shoulders http://www.bbc.co.uk/science/humanbody/body/factfiles/joints/gliding_joint.shtml

Movable Joints Hinge Joint – allows movement in only one direction like a door Ex. Elbows, knees fingers and toes http://www.bbc.co.uk/science/humanbody/body/factfiles/joints/gliding_joint.shtml Pivot Joint – allows movement from side to side A bone rests and rotates on one spot back and forth Ex. Neck, elbow and knees (also hinge joints)

Movable Joints Gliding Joint – where several bones come together like a puzzle and can slide past one another Ex. Wrists and ankles http://www.bbc.co.uk/science/humanbody/body/factfiles/joints/gliding_joint.shtml