The Skeleton and Muscles

• functions of the skeleton - support, shape, protection, movement and manufacture of blood cells
• axial skeleton - skull, facial bones, spine, ribcage and sternum
• appendicular skeleton - limbs, pertoral girdle and pelvic girdle
• skull - protects the brain and is made of 22 bones that are fused together except for the lower jaw which can move to open the close the mouth
• Spine - consists of 33 bones (vertebrae) arranged into 5 regions
• the vertebrae enclose the spinal chord for protection - a pad of fluid enclosed by cartilage called a disc, located between most of the vertebrae
• these discs act as shock absorbers and protect the vertebrae from rubbing against each other#
• cervical - 7 vertebrae
• thoracic - 12 vertebae
• lumbar (small of back) - 5 vertebrae
• sacrum 9hip) - 5 vertebrae
• cocyx (tail) - 4 vertebrae
• the ribcage protects the heart and lungs - 7 true ribs, attached to the breastbone and spine - 3 false ribs, attached to the spine and each other at the front of the chest - 2 floating ribs, attached to the spine
• bone is dense connective tissue that forms that major part of the skeleton
• compact bone is composed of bone cells called osteoblasts
• compact bone also contains blood vessels and nerve fibres
• spongy bone looks like a sponge when viewed under the microscope and is found mainly in the epiphysis of log bones - function is to give strength and rigidity to bones without making them too heavy
• red bone marrow is active in making blood cells
• yellow marrow is inactive and contains numerous fat-storage cells - can convert to active red marrow if required
• cartilage is a flexible material that consists of protein fibres embedded in a rubbery matrix - protects the ends of long bones and acts as a shock absorber - lacking in blood vessels and nerves
• bone forming cells are called osteoblasts - digest and remove old bone
• physical activity stimulates osteoblasts which results in stronger bones - pituitary gland
• ligaments connect bone to bone and are made of string slightly elastic fibres - prevent excessive movement of bones at a joint
• tendons connect muscle to bone and are strong, flexible, inelastic fibres
• a joint is where two or more bones meet
• immovable (fixed or fused) joints include the scull and pelvic girdle
• the junction between fused bones is called a suture
• slightly movable - the joints between vertebrae in the upper spinal column are slightly movable
• freely movement (synovial) the ends of the bones are covered with cartilage and the bones are separated by a cavity - the bones are held in place in place by ligaments which prevent excessive movement of bones at joints
• synovial fluid is found between the bones - fluid lubricates the joint and reduces friction at the joint
• example of synovial joints - ball and socket joints
• arthritis cause - wear and teat to cartilage in the joints
• arthritis prevention - prevented by reducing wear and tear on certain joints
• arthritis treatment - rest, weight loss, special exercises
• anatagonistic muscles are pair of muscles that work opposite to each other - the bicep contract while the triceps relax whe