Gill Sans Bold
Senior Science
Preliminary Course
Stage 6
Humans at work
Part 5: Brain protection
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Gill Sans Bold
Senior Science Stage 6 Preliminary Course
Water for living
Plants
Humans at work
•
Human body and injury
•
Protecting the respiratory system
•
Protecting our sight
•
Sounds in the environment
•
Brain protection
•
Movement without injury
Local environment
Contents
Introduction ............................................................................... 2
The brain and its protection....................................................... 4
Examining a skull .................................................................................4
Head injuries ............................................................................. 6
Types of head injuries..........................................................................6
Prevention of head injuries ................................................................10
Suggested answers................................................................. 15
Exercises – Part 5 ................................................................... 17
Part 5: Brain protection
1
Introduction
The brain is a vital organ for the fully functioning human. This organ
must be protected from damage. The skull naturally forms a barrier
between the brain and the environment. Helmets and headgear protect
the head (especially the brain) in the workplace, while playing sport and
during recreational activities. In this part you will examine the types of
injuries a brain can sustain and the use of protective headgear.
In this part you will be given opportunities to learn to:
2
•
identify the role of the skull in protecting the brain
•
define the term concussion
•
describe the effects of bruising of brain tissue and blood vessels
•
discuss the energy transfers and transformation involved when a
hard hat or helmet protects the head from injury
•
discuss the relationship between the design and use of hard hats and
safety helmets in areas of building construction and sport
•
describe situations in which hard hats and safety helmets are used.
Humans at work
In this part you will be given opportunities to:
•
process and analyse information by examining a model human skull
to measure the thickness of bone and inferred strength of the bone
•
identify data sources, analyse and present information on
laws/regulations governing the use of safety helmets and hard hats
and use available evidence to discuss how the design of the
protective headgear is related to activity in one of the following
–
football headgear
–
softball helmet
–
hard hats
–
cricket helmets
–
bike helmets.
Extracts from Senior Science Stage 6 Syllabus © Board of Studies NSW,
November 2002. The most up-to-date version is to be found at
http://www.boardofstudies.nsw.edu.au/syllabus_hsc/index.html
Part 5: Brain protection
3
The brain and its protection
The skull is composed of 22 bones.
The part of the skull that encloses
the brain is called the cranium.
Human skull with brain enclosed.
Examining a skull
In this activity you will examine a model of a human skull and measure the
thickness of the bones to infer the strength of the bone.
Obtaining a model of a skull may be difficult, but not impossible.
Think laterally. Where could you find a model of a skull? Could you
visit a local TAFE College, a local high school, your doctor’s surgery,
the hospital, St. John’s Ambulance or Red Cross where they conduct first
aid classes, the ambulance station. Do you know a medical student?
Let your fingers do the walking and telephone before you go, to make the
most efficient use of your time. Be persistent. Make sure the person
answering your query knows what you want and why you want it.
If they understand your situation they are usually more willing to
help you.
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Humans at work
When you ‘track down’ your skull, examine it closely.
•
Count the number of bones.
•
Examine the suture joints where skull bones have come together.
•
Determine which part of the skull is the thickest and which part of
the skull is the thinnest. Consider why this might be so.
•
Estimate the thickness of the bone eg. 3 mm.
•
Draw a diagram of the skull.
•
Label the diagram. If you do not know the scientific name for the
bones and parts of the skull, label the diagram using descriptive
labels. For example, where the spinal cord goes through the skull.
Ask your source if they have other skulls. They may have a baby’s skull
or a series of skull replicas to illustrate the evolution of humans.
Compare the thickness of the bones and the suture joints.
If you are unable to obtain a model of a skull, research the thickness of
the bones of the cranium and the strength of bones from secondary
sources.
Information may be found in anatomy and physiology text books.
You should also find information on the Internet by using a search engine or
going to the www.lmpc.edu.au web site.
A human skull and baby’s skull. (Photo: Yvonne Kinch)
Record your observations in Exercise 5.1: Skull strength.
Part 5: Brain protection
5
Head injuries
Any head injury is vitally important. Except for very minor injuries, all
head injuries should receive expert medical attention. Jarring of the brain
within the skull can cause bruising or bleeding. Bleeding from the ears
after an accident can be an indication that a major head injury has
occurred.
Types of head injuries
Read the accident/case history of Dimi Done as described below.
The accident occurred on Monday 16 at 7.20 am in Tinterland Rd.
The weather conditions were poor, drizzling rain on a dull and overcast
day. The road surface was good, but it was wet and slippery. At the site
of the accident there was a 60° curve in the road and the road signs
indicated a maximum speed 45 kph.
The driver was exceeding the speed limit and lost control of the car in an
attempt to negotiate the curve. The car left the road, mounted the curb
and crashed into a light pole.
The driver was flung forward by the impact sustaining head injuries to
the front of the skull as it collided with the windscreen; chest injuries as
the steering wheel compressed the rib cage; and severe leg injuries as the
engine was pushed back into the cabin of the car, encasing both legs.
Today Dimi is blind and confined to a wheelchair, a partial quadriplegic.
Dimi’s chest and leg injuries healed very well, but her brain injuries did
not.
The front of Dimi’s skull impacted with the windscreen. The brain
moved forward inside the cranium, hit the front of the skull and bounced
back to hit the rear of her skull. This ‘bouncing’ around of her brain
inside the cranium caused extreme bruising and bleeding of the brain
tissue and blood vessels.
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Humans at work
As the tissue haemorrhaged, the pressure built up within the cranium
causing further damage. Surgeons drilled holes in the cranium in an
attempt to relieve the pressure with little success.
The area of visual perception is the located at the rear of the brain.
At the time of impact the brain continued with the inertia of the body,
striking the front of the skull then the rear of the skull, damaging the
visual region. The pressure created by the bleeding further damaged the
area, resulting in Dimi’s blindness.
The sensory areas of the brain which receives sensations from the skin,
muscles and gut is located slightly behind the centre of the brain.
Damage can occur on the opposite side of the brain from the site of the
injury.
general sensory area
primary motor area
premotor area
somesthetic
association
area
frontal eye
field area
visual
association
area
frontal lobe
primary
visual
area
occipital lobe
temporal lobe
auditory
association
area
primary
auditory
area
Functional areas of the cerebrum. A lateral view.
Describe the effect of ‘bouncing’ a brain around in a skull.
_________________________________________________________
_________________________________________________________
_________________________________________________________
Check your answers.
Part 5: Brain protection
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Cerebral compression
Cerebral compression is the condition which occurs when pressure
within the skull increases. The pressure caused by the bleeding or the
swelling of the injured brain tissue compresses the brain, restricting the
blood vessels, which may cut off oxygen to parts of the brain.
Disability or death may result.
Fractures or ‘cracks’ in the cranium tend to heal by themselves, unless
the fracture is compressed. A compressed fracture is when the bone is
depressed into the tissue. Surgical treatment will be necessary to remove
the bone fragments to prevent damage to the underlying tissue.
haemorrhage
cerebrum
cerebellum
medulla oblongata
Haemorrhage (bleeding) compressing the brain.
Concussion
Concussion is a temporary impairment of the brain function caused by
jarring or shaking. Mild concussion may involve a brief loss of
consciousness followed by a headache. Severe concussion may lead to
prolonged unconsciousness and even disruption of respiration. A person
recovering from concussion should be carefully observed for signs of
bleeding or increased pressure within the cranium. These can result from
bruising of brain tissue or blood vessels.
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Humans at work
Expectations reversed
The home team was favoured to win. Through both halves the teams
had matched each other stride for stride. With the score at 3–3 the
game depended on Muggleton, a creative young player who makes
things happen. He would be hard to beat.
With only seconds remaining Muggleton made a magnificent dash
down the line fighting desperately for the opportunity to break
through the oppositions defence and score. Artfully dodging player
after player he was in full stride - then it was all over. He went down
like a crumpled bag of chips. Corey brought him down ramming him
heavily into the field.
Muggleton was down and out for about sixty seconds. When he came
around he had no recall of his stupendous run or how close he had
come to saving the game. After three hours observation at the hospital
he was cleared of major injury and diagnosed as suffering from a
general concussion. He was suffering nausea and giddiness, plus a
giant sized headache. Muggleton still has no recollection of the game.
Kobinson Chronicle
Symptoms of concussion include:
•
short or extended periods of unconsciousness
•
‘seeing stars’ or double vision
•
confusion
•
temporary loss of memory of events just before the injury
•
giddiness
•
nausea
•
vomiting
•
headache
•
numbness and tingling in arms and legs
•
stumbling and lack of eye/hand coordination.
Someone who has had a blow to the head is often described as ‘punch
drunk’. This is a term derived from the boxing profession. Boxers who
have experienced many ‘knockouts’ and blows to the head may have
been concussed many times. This shaking and bruising of the brain
tissue and the blood vessels and nerves in the cranium may result in some
permanent damage. A ‘punch drunk’ person may suffer form
uncoordinated movement, slurred speech, poor concentration and
forgetfulness.
Part 5: Brain protection
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1
Concussion may occur in many situations. Make a list of the possible
situations where you think concussion may occur.
_____________________________________________________
_____________________________________________________
_____________________________________________________
2
Describe how you would feel if you had concussion.
______________________________________________________
______________________________________________________
3
What does the term ‘concussion’ mean?
______________________________________________________
Check your answers.
Prevention of head injuries
Head injuries can be severely damage life functions, so prevention is
essential. Legislation has been passed to prevent and minimise the risk
in some areas. To reduce the incidence of head injuries, it is compulsory
to wear a seat belt in cars, wear safety helmets on construction work sites
and when riding a motorbike or a bicycle.
Helmets are designed for specific purposes. A hard hat provides
sufficient protection from falling debris on an industrial worksite, but
does not provide sufficient protection when riding a motorcycle or
travelling in a dune buggy.
Complete Exercise 5.2: Design solution now.
List the occupations and activities that require head protection.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
Check your answers.
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Humans at work
Hard hats and the law
Legislation has been passed which has made the wearing of hard hats and
helmets in certain situations compulsory. WorkCover enforces this
legislation.
Hard hats must be worn in confined areas. There may not be sufficient
room for an employee to stand upright and there is a risk of the employee
hitting his head on low girders or low level machinery. Hats must be
worn in areas where falling debris could strike people on the head, like
small tools, bolts and rivets. The hat will take the blow of the falling
object and deflect it.
The hard hat is two layered. There is an outer layer and an internal
suspension. Between the two layers there is a space filled with air.
The suspension fits snugly to the head and should be adjusted for the
individual wearer.
Hard hat interior and exterior view. (Photo: Yvonne Kinch)
Another sort of law
Energy cannot be created or destroyed. It can be transferred and
transformed from one form to another. This is the law of conservation of
energy.
Energy is transferred from one body to another without changing form in
an energy transfer. The most common example is where one body hits
another and transfers some or all of its kinetic energy to the other body
like a golf club hitting a golf ball. Where energy is transferred, work is
done by the one body on another.
Part 5: Brain protection
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A falling body has potential energy due to its height and the force of
gravity. As it falls, the potential energy is transformed into kinetic
energy (energy of movement). When a falling body hits an object,
energy is transferred to that object. Some energy is usually transformed
into sound energy.
If a falling object hits a person’s hard hat, some of the kinetic energy will
be transferred into sound (you hear the object hit the hat). More energy
will be transferred through the material of the hard hat into the air space
between the hard hat surface and the inner suspension. The space
between the two layers will absorb the energy of the impact.
The suspension webbing will also absorb energy before any energy is
transferred to the bones of the skull.
Objects such as packets of cigarettes, gloves and earplugs should not be
stored in the space between the suspension and the hat. These objects
could transmit large forces to the head and neck resulting in serious
injury.
Hard hat design
If a hard hat has suffered a ‘hit’ it should not continue to be used.
The deformation of the hard hat by the blow of the object may have
altered the properties of the hard hat. Hard hats have a use by date (the
inner suspension approximately 12 months: the entire helmet five years).
At the time of production, a date is moulded into the hat, after which the
hat should be thrown away as it may have deteriorated. This ensures
hard hats always provide maximum protection.
After each use hard hats should be inspected for any breakages, cracks,
craze pattern, discolouration, chalky appearance, brittleness, stretched or
frayed webbing or changes in the suspension. Exposure to chemicals,
extremes of heat or cold and sunlight can also affect the efficiency of the
hard hat.
All hard hats must meet set standards. In Australia these are AS 1801
Standards and in the United States the ANSI-Z89.1-1997 Standards.
The standards provide minimum performance requirements to reduce
forces of impact and penetration from falling objects and, where
applicable, provide protection from electrical shocks.
In the United States, helmets are required to withstand the force of a
3.63 kg (8 lb) steel ball free falling from a height of 1.524 m (five feet),
and a pointed 1 kg (2.2 lb) steel penetrator, with a 60° angle at the point,
dropped from a simulated free fall height of 1.2 m (four feet).
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Humans at work
The penetrator can’t make contact with the head form.
Electrical protection can be from 2200 volts (Class G helmet) to
22 000 volts (Class E).
Type I helmets (hard hats) provide protection from impact on top of the
head and Type II helmets (hard hats) provide protection from the top and
off-centre, from the side. Hard hats are composed of high density
polyethylene and vary in design, smooth crown to ridged crown.
The development of hard hats or a specific helmet came about to meet a
particular need – personal protective equipment.
B
A
P.
.6
A
Code for the type of material used
to make the hard hat
S
P
C
P.
P.
11 12
1
2
10
9 4
9
3
8
This marking which is moulded into
the hat indicated the ‘life of the hat’
4
7
6
5
December 1994
SAFETY CAP
The ticks indicate that the article
meets the Australian Standards
There must always be five ticks
Australian
Standards
AS 1801 Lic. No 71
Markings on a hard hat
Complete Exercise 5.3 Energy and hard hats and Exercise 5.4: Sporting
helmets.
Part 5: Brain protection
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Humans at work
Suggested answers
Types of head injuries
‘Bouncing’ a brain around a skull causes bruising and bleeding.
Pressure builds up in the skull when brain tissue haemorrhages.
Impacts on particular parts of the brain may cause brain damage eg. loss
of speech.
Concussion
1
Situations where concussion could occur include: car accidents (the
head is thrown forwards and then jerked backwards, the brain
contained in a rigid bony box is banged into the front of the skull and
then into the back of the skull as it moves backwards and forwards);
fights; objects falling or dropping on the head eg. at a construction
site; falls off skateboards, bicycles, roller blades or rollers skates; a
heavy fall onto the feet where the force is transferred up the spine to
the skull and brain.
2
A concussed person could be unconscious or see ‘stars’, be
confused, nauseous and giddy with a headache.
3
Concussion means a temporary malfunction of the brain.
Prevention of head injuries
Situations in which head protection may be required include the
following: building construction sites, mining, firefighting, underground
sewerage works, electrical power line work, steelworks, oil and gas,
paper manufacture, welding, football, cricket, baseball, gridiron
(American football), cycling, motorcycling.
Part 5: Brain protection
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Humans at work
Exercises – Part 5
Exercises 5.1 to 5.4
Name:_______________________________
Exercise 5.1: Skull strength
What did you use – real skull, replica, Internet site, book? __________
a)
Record the observations you made during your examination of a
skull.
_____________________________________________________
_____________________________________________________
_____________________________________________________
b) What can you say about the strength of a skull?
_____________________________________________________
_____________________________________________________
Exercise 5.2: Design solution
An egg dropped from a considerable height will not break if it has
sufficient protection.
Design a suitable form of protection for an egg to prevent it from
breaking when dropped from a height of no less than two metres.
To determine if your solution will ‘work’ you must construct and test
your device, record and evaluate your results and suggest possible
modifications and improvements to your design.
1
As you think about the problem and consider the various aspects,
keep notes of your thoughts and ideas. Keep a record of what you
have done to develop your ideas and find information. This is a
process diary or logbook.
2
Draw a plan of your suggested egg helmet.
Part 5: Brain protection
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3
Construct your egg helmet.
4
Test your egg helmet design prototype.
5
Record the results of your test.
6
How successful was your egg helmet design? What improvements,
if any, would you make to your design?
The following points are suggestions to start your thinking
•
What shape or form will your egg helmet take?
•
What material will you use to make your egg helmet?
•
How will you assemble it?
•
What forces will be operating?
•
In which directions will the forces be operating?
•
Could you do any research to discover if this problem has been
solved by someone else? Where would you look for information?
•
Collect the materials you will require to make your design for an egg
helmet.
In your report you will need to include:
•
a process diary (log book)
•
drawing of the plan of your protection device (egg helmet)
•
description of the method used to test your protection device
•
results of the testing of the protection device
•
evaluation of the results and the success of the protection device
•
suggestions and improvements that could be made to the design of
the protection device.
Exercise 5.3: Energy and hard hats
Discuss how hard hats provide head protection. Include a description of
energy transfer and transformation. You may provide a diagram.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
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Humans at work
Exercise 5.4: Sporting helmets
In this exercise you will analyse and present information on
laws/regulations (legislation) covering the use of hard hats and safety
helmets. You will also look at the design of protective headgear.
How will you go about finding the information?
You could telephone or write to the manufacturing companies of the
helmets and ask for copies of their brochures and the specifications of
their products.
You could telephone or write to government and legislation bodies and
ask for copies of the relevant rules and regulations.
You may be able to contact the occupational health and safety officer in a
local company to gain information on the regulations concerning the use
of hard hats. Your police station may be able to provide you with
information on laws regarding the wearing of bike (motor bike/bicycle )
helmets. Sporting stores could be a source of the different types of
sporting headgear and would be able to supply the names of companies
and products. You may be able to obtain promotional material and write
and request information from the companies.
If you have access to the Internet, much information can be obtained.
Part 5: Brain protection
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1
Darryl Halligan is a rugby league football player. When he plays he
wears a helmet. He does remove his helmet when he attempts a
goal kick. The wearing of a helmet during a competition match is a
personal choice. List the advantages of wearing a helmet.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
2
Compare the design and styles of football headgear, softball helmets
and cricket helmets. Discuss how the design is related to the
activity.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
3
Investigate the laws and regulations governing the use of bicycle
helmets.
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
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Humans at work
Softballer with softball helmet.
Cyclist with helmet.
Motorbike helmet.
Cricketer with cricket helmet.
Part 5: Brain protection
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