Skeletal System

3 functions of the skeleton  Movement – joints Shape/Support – keep us upright Protection e.g. the skull and other

organs.

JointsThe Hinge Joint This includes the Elbow and the Knee Joint.

It is Capable of Bending (Flexion) and Straightening (Extension) E.g.

the elbow flexes on a bicep curl, and extends to straighten the arm.

The knee joint, flexes when a footballer prepares to kick the ball and then extends to strike the ball.

The joint is connected by 2 smooth shallow surfaces and held in place by strong Ligaments

JointsThe Ball and Socket Joint This includes the Hip Joint and the Shoulder Joint.

It is capable of flexion, extension, adduction, abduction and rotation.   It is called a ball and socket joint as one bone such as the Humerous

(arm) is a long bone with a ball like end and the other is a cub shaped socket (shoulder) in which the femur fits in to. These are covered in cartilage and held in place by ligaments.

Examples include Bowling in cricket (forward rotation), swimming back crawl (backward

rotation) Abduction occurs as the arm is brought behind the body in preparation

to throw a ball or javelin.

Movements

The effects of exercise on the bones:

Positives Increase in Bone Density (heavier and stronger) Ligaments (which attach bone to bone) and tendons

(which attach bone to muscle) become thicker and stronger. This increases joint flexibility and allows more power in movement.

Negatives: Too much exercise on hard ground can cause stress

factures Young people should be careful not to do too much of

activities such as weight lifting or cross country as it can cause bones (which are still growing) to develop unevenly.

Effects of exercise on the Skeletal System

Increases bone density when bones become heavier and stronger Ligaments (bone to bone) and Tendons (bone to muscle) become thicker

and stronger increasing joint flexibility and more power of movement

Weight-bearing exercise

As people get older their bones become lighter and their density and strength is reduced. If too much is lost i.e. due to lack of activity or nutrients then the skeleton can become weak this is called Osteoporosis.

Putting weight and pressure on certain bones by doing activities such as walking, running, aerobics etc can help strengthen bones.

Yoga is also a useful weight bearing exercise as it also improves balance, reducing the chances of falling.

The effects of Diet on the skeletal systemhttp://www.youtube.com/watch?v=waTOl1Orkt8

CALCIUM!!!!! – helps bones grow and increases density

Sources: milk, cheese, yoghurt Vitamin D – bone growth, healthy bones and

absorption of calciumSource: sunlight

Smoking and too much alcohol have a toxic effect on bones by making them more brittle

Injuries to the skeletal System

Fractures

A fracture is a cracked or broken bone.

Closed Fracture – the skin is not broken or damaged

Compound Fracture – the broken bone protrudes (sticks out) through the skin.

Simple Fracture – fracture takes place in one line, no displacement of the bone, only part of the bone breaks.  Stress Fractures

These can occur due to: overuse a result of the muscle become fatigued and unable to absorb shock. increasing the amount or intensity of exercise too rapidly using hard surfaces Poor fitting shoes.

Joint Injuries

Tennis/Golfers elbow Overuse injury – pain around the elbow.

Dislocations This is when a bone at a joint is forced out of its normal position caused by a hard impact. The most obvious sign is deformity and swelling at the joint. Sprains

A sprain is a damage ligament (A strain is a torn/pulled muscle), this occurs such as a twisted ankle in netball or football.  

These usually occur due to twisting or stretching too far past the normal range of a joint due to falling, twisting or colliding with another player.

Torn Cartilage   Cartilage is a firm elastic substance found at the ends of the bones of a synovial joint. Tearing it for example at the knee, can often be cause by pivoting on one foot. If the

cartilage is torn the sufferer will often be in pain and fall to the ground. 

Treatment

  R- Rest – stop playing or training I – Ice – apply ice to reduce any

swelling. C – Compression – use pressure to apply

the ice pack and help relieve pain E – Elevation – keeping the injury raised

can reduce swelling

LifestyleDiet Calcium – helps bones grow and increases bone density

(strength) e.g. milk, cheese Vitamin D – is needed for growth, healthy bones and to

absorb calcium. It is made in the body through exposure to sunlight.

Weight Bearing exercise Prevents Osteoporosis

Smoking and alcohol Have a toxic effect on bones and can cause weakening