Body in Action Movement Mr G Davidson

Movement All day, every day, our bodies are continually moving. People use many different kinds of movement when they play sports. Bones support our body weight.

Movement Muscles allow our bodies to move. We must be able to move our bodies in a controlled way and our sense organs help us to do this. This control is unconscious and is known as coordination.

The Skeleton The skeleton has three functions: Support Movement protection

The skeleton Skull Mandible Vertebrae Clavicle Scapula Sternum Humerus Rib Vertebrae Pelvis Ulna Radius Carpals Phalanges Femur Patella Tibia Fibula Tarsals Phalanges

Structure of the Bone Bone is made up of living cells which form flexible fibres. These are supplied with food and oxygen by blood vessels. The fibres are surrounded by hard minerals mainly calcium phosphate. Our bones grow as we get bigger, providing a hard, strong framework.

Structure of the Bone

Composition of Bone Inorganic minerals make bones hard and strong. The organic parts, the living cells, give the bones flexibility. If the minerals are removed from a bone by soaking it in acid, the bone becomes very soft and pliable (rubbery). If the organic parts are removed by burning the bone, it becomes very brittle.

Joints Joints are found at many places in the skeleton. They are formed where bones of the skeleton meet. Joints allow different kinds of movement, E.g. Ball & socket at the hip and shoulder Hinge joint at the elbow and knee Gliding joint at the ankle and wrist.

Structure of a Joint

Structure of a Joint

Structure of a Joint Structure Function Ligaments Hold the bones in place Synovial fluid Lubricate the joint Synovial membrane Secretes synovial fluid Cartilage Shock absorber to protect the ends of the bones

Structure of a Joint

Human Arm Our arms and legs provide mobility. Muscles are joined to bones by TENDONS. When a muscle contracts, the tendon pulls the bones and the arm moves.

Human Arm Movement is brought about by pairs of muscles which work against each other. If one muscle bends the arm, then another will straighten it. Muscles which work in pairs like this are called ANTAGONISTIC pairs.

Arm Movement Biceps contracts Triceps relaxes Biceps relaxes Triceps contracts Arm Bends Arm Straightens

Sports Injuries Strenuous activities like sports can cause injury to joints and muscles. Some parts of the body are more likely to be injured than others, e.g. legs. The kinds of injuries you are likely to get are affected by the movements you make while playing each sport. Most injuries are caused by sudden changes in movement.

Sports Injuries Footballers sprain knees and ankles damaging ligaments. Runners suffer from torn muscles and tendons. Direct blows can cause fractures.

Types of Fracture Spiral fracture – e.g. a tennis player turns sharply. Green-stick fracture – usually found in children where the bone doesn’t snap completely but resembles a broken twig. Simple fracture – when the bone breaks but doesn’t break the skin. Compound fracture – when the bone breaks and does break the skin.

Spiral Fracture

Green Stick Fracture

Simple Fracture

Compound Fracture

Arthritis The joints swell up and hurt and movement is difficult. There are 2 kinds of arthritis.

Osteo-arthritis This occurs usually in older people. It is due to the everyday wear and tear of the joints. The smooth cartilage begins to break down so the joints lose their shock-absorbing properties. The bones no longer move smoothly against each other as the surfaces of the cartilage are bumpy.

Osteo-arthritis

Rheumatoid Arthritis Connective tissue grows into the joint cavity and gradually hardens. The two bones become joined together, making movement impossible. This kind of arthritis can run in families and may start at any time, even in young people.

Rheumatoid Arthritis

Tendons and Ligaments Although tendons and ligaments look similar, they are structurally different with different functions. Tendons attach muscle to bone. Ligaments attach bone to bone.

Tendons and Ligaments