The functions of the skeleton (as part of a healthy, active body)
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Transcript of The functions of the skeleton (as part of a healthy, active body)
3 categories of joint
• Fibrous or fixed - no movement
• Cartilaginous - slight movement
• Synovial - freely moveable
gliding
• When two flat surfaces glide over one another
Eg carpal bones in wrist when playing hockey
Ball and socket
• When a round head of bone sits in a socket – allows wide range of movement
Eg hip, shoulder
Cartilage Ligaments
• Soft connective tissue• Babies skeleton is
mainly cartilage – through process of ‘ossification’ mostly becomes bone
• Has no blood supply
• Connective tissue between bones
• Tough, resilient, keep joints together & stable
• Prevent extreme movement
• Resist dislocation
3 main types of cartilage
• Yellow elastic - flexible (ear lobe)
• Hyaline (blue) articular - on articulating surfaces of bones. Protective - allows movement by limiting friction. Thickens through exercise
• White fibro - tough shock absorber, eg semi-
lunar cartilage in knee joint
Cartilage & ligament injuries
• Repeated small injuries can lead to cartilage tears
• Degeneration (wear and tear of meniscus cartilage)
• Cartilage is slow to heal as it doesn’t have a blood supply
• Ligaments can sprain or tear• Medial/cruciate – common knee ligament
injuries
Q’s
• 1. explain how the skeletal system responds to exercise (5)
• 2. name the two most common forms of arthritis and describe their causes (6)
• 3. which category of person is most likely to suffer from osteoporosis and what factors could contribute to this (3)
Answer 1
• short term – in joints stimulates secretion of synovial fluid, which becomes less viscous = greater range of movement
• longer term – connective tissue becomes more flexible. With time improved range of movement becomes more sustained. Bone increases in density = stronger = less risk of osteoporosis. Hyaline cartilage, tendons and ligaments thicken = reduced risk of injury. Bone mineral content higher
Answer 2
• Osteoarthritis – caused by ageing and general wear and tear, injury, overweight
• Rheumatoid – immune system attacks cells within joint capsule. Women more at risk, also genetic predisposition, smoking and obesity