The functions of the skeleton (as part of a healthy, active body)

• Shape and support

(allowing good posture)

• Movement

Muscles attach to bones and create movement (levers) around joints

• Protect internal organs

• Produce red and white blood cells

• Store minerals

Task

• Label the bones on the skeleton

3 categories of joint

• Fibrous or fixed - no movement

• Cartilaginous - slight movement

• Synovial - freely moveable

Hinge joint

• Movement in one plane only

• Eg knee, elbow

Pivot joint

• Only allows rotation

Eg neck vertebrae when turning head

ellipsoid

• Biaxial movement i.e. in 2 planes

Eg playing a badminton shot

gliding

• When two flat surfaces glide over one another

Eg carpal bones in wrist when playing hockey

Saddle joint

• When concave surface meets convex as in thumb gripping tennis racket

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

Movement at joints

• Flexion

• Extension

• Abduction

• Adduction

• Rotation

levers

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

Answer 3

• Women over 60

• Inadequate calcium and vitamin D intake

• Lack of weight bearing exercise