3Ossification and Composition The bones of embryos are made largely of cartilage. They are soft.The process of ossification uses calcium to create bone as the child grows and matures.The skeleton has over 200 bones.
4Bone Growth Bones gradually become hard and strong. With age bones lose their density and strength. When severe this is called osteoporosis.Eating foods containing calcium and exercising regularly helps bones to develop and stay stronger for longer.
6Joints and their function A joint is where two or more bones meet.Synovial jointsCartilage reduces friction. Acts as a shock absorber.Synovial fluid lubricates the joint.Synovial membrane produces synovial fluid.Tendon joins muscle to bone enabling movement.Ligament joins bone to bone, stabilising the joint.
7Joint actions Abduction Movement away from the mid-line of the body Adduction Movement towards the mid-line of the bodyExtension Straightening limbs at a joint – moving bones apartFlexion Bending the limbs at a joint. –moving bones towards each otherRotation A circular movement around a fixed point
8Types of Joint Hinge Elbow, knee, fingers; Movement=Flexion, extension Ball and Socket Shoulder, hipMovementFlexion, extension, abduction, adduction, rotationPivot Between the atlas and axis in the neck
9General Functions of the Human Skeleton Protection - the cranium and ribs protect the brain and vital organs in the chest.Shape - gives shape to the body and makes you tall or short.Support - holds your vital organs in place when playing sport. The vertebral column holds the body upright.Movement - muscle are attached to bones, which are jointed. When the muscles contract the bones move.Blood production - red blood cells (to carry oxygen) and white blood cells (to protect against infection) are produced in the bone marrow of some bones.
10VertebraeCervical Vertebrae – supports the head and the neck and allows it to nod and rotateThoracic Vertebrae – ribs are attached making a protective cage. It allows some movement bending forward and backward and side to sideLumbar Vertebrae - allows much flexibility; bending forward and backward and side to side but is prone to injurySacral Vertebrae – these are fused together and make a strong base. Transmit force from legs to upper bodyCoccyx – fused vertebrae with no special use
12Importance of diet and exercise Bone can change in strength, density and shape. The body does most of its bone building during the first 30 years of life. Bone is constantly being broken down and replaced, however, bone loss begins to outpace bone growth between the ages of 30 and 35.You can maintain bone strength by increasing intake of calcium, vitamin D and fibre. Also doing weight bearing exercise e.g. walking, jogging, bicycling, tennis, basketball, soccer and dancing.
13Importance of bones in terms of body size Heavier people have stronger bones as the bones respond to the weight that they have to carry. Therefore they tend to be better at sports like rugby or wrestling.People with smaller bones tend to be better at flexible sports e.g. gymnastics or dance.Your bone structure is most influenced by your genes