Musculoskeletal

Maintain posture and produce movement

fascicles - bundle of muscle fibers (cylindrical multinucleated cells) - made of thread like parallel myofibrils- myofilaments fibres held together by perimysium each fibre surrounded by sarcolemma 2 types of myofilaments - actin (thin) - myosin (thick)

M line- middle, actin only Z line- anchors actin I band - actin only A band - overlapping actin and myosin H Zone- actin only

muscle fibre is supplied with energy and activated by a nerve impulse actin slides over the myosin, shortening the sarcomeres, which shortens the muscle fibre 1- myosin heads split ATP and gain energy 2- heads bind to actin (cross bridges) 3- heads rotate to centre of sarcomere 4- heads bind ATP crossbridges detach from actin

elasticity, extensibility, contractibility

pairs of muscles that work opposing each other extensor- contract to extend flexor- contract to flex/bend origin- end of muscle fixed to the stationary bone insetion- end of muscle to the movable bone furtherest from middle of body tendons join muscle to bone ligaments join bone to bone

body shape and support allows for attachment of muscles protection of vital organs storage of minerals and fats blood cell production

Axial- skull, vertebrae, ribs and sternum Appendicular- pelvis, shoulders, upper and lower limbs

epiphysis- bone end epiphyseal line- growth plate Articular cartilage- protects bone ends spongy bone- contains red marrow, site of blood cell production compact bone- made of haversian systems - osteons diaphysis- bone shaft, hollow cylinder of compact bone medullary cavity- yellow bone marrow for fat storage periosteum- outer covering of bone metaphysis- where diaphysis and epiphysis combine nutrient foranen- allows artery and vein to enter

inorganic matrix of calcium- hard organic matter such a collagen- soft bone cells - osteocytes- mature - osteoblasts- young bone building - osteogenic- stem cells - osteoclasts- breaking central canal contains blood vessels and neurons

irregular arrangments of thin bony plates called trabeculae large spaces filles with red bone marrow for blood cell production osteocytes

chondrocytes- mature cartilage cells matrix- lucanae strucutral support and protective cushioning no blood supply chondrin- matrix collagen- cartilage fibres chondoblasts- young builders

hyaline - matric with embedded cytes, closely packes - strong and flexible - ends of bones, joints, trachea rings fibro - parallel bundles of thick collagen fibres - slightly compressible - invertebral discs elastic - elastic fibres and losely packed collagen fibres - flexible and retains shape - external ear

fibrous - joined by fibrous tissue - immovable - cranium cartilaginous - limited movement - ribs to sternum synovial - range of movements depending on type - structure- joint capsule, synovial membrane with synovial fluid, ligaments - knee, hip, shoulder

Ball and Socket o 3 planes of movement –circumduction o E.g. shoulder and hip including names of articulating bones Hinge o 1 plane of movement to bend (flex) or straighten (extend) o E.g. elbow and knee including names of articulating bones Pivot o rotational 1 plane o E.g. 1st and 2nd vertebrae in neck, radius and ulna in forearm Gliding o 1 plane back and forth, sliding o E.g. carpals and tarsals Saddle o 2 planes, back and forth, side to side o The only location is the thumb condyloid - wrist and ankles - 2 planes of movement

• Bone density determined by dietary intake of calcium, weight bearing activity and genetic inheritance • Loss of calcium from bones occurs more quickly than replacement leading to a loss of bone density • Increased risk of fractures, curved spine, shortened height • Prevention – regular weight bearing activity, good dietary calcium intake • More common in post-menopausal women

• Loss of cartilage between joint due to wear and tear • Friction between joints, inflammation, pain and limited movement at joint • Prevention – maintain healthy weight range • Treatment – pain and anti-inflammatory medication, joint replacement, aids for carrying out daily activities