Download Skeletal System

Skeletal
System
3 functions of the skeleton
 Movement
– joints
 Shape/Support – keep us upright
 Protection e.g. the skull and other organs.
Joints
The Hinge Joint
This includes the Elbow and the Knee Joint.
It is Capable of Bending (Flexion) and Straightening (Extension) E.g.
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the elbow flexes on a bicep curl, and extends to straighten the
arm.
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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
Joints
The Ball and Socket Joint
This includes the Hip Joint and the Shoulder Joint.
It is capable of flexion, extension, adduction, abduction and rotation.
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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
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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
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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 system
http://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 calcium
Source: sunlight
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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
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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
Lifestyle
Diet
 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