Preliminary Senior Science – Summary

Humans at Work

1. The human body can have demands placed on it which can result in injury

outline reasons for the Occupational Health and Safety Act 2000

The reason for the act is to: Ensure the safety of all employees To promote improvements in working environment To account for the increasing injuries in NSW

define a hazard in the workplace as anything with the potential to harm life, physical and mental health or property

A hazard is anything that has the potential to harm life, physical and mental health or property.

assess potential sources of risk in an area in terms of causes

Potential sources of risk are physical, chemical or biological: Physical : noise, dust and radiation Chemical : fire, poisons, and toxic chemicals Biological : disease, organisms, parasites

identify hazards in the workplace that increase the risk of injury

In the workplace there are many hazards which cause and increase the risk of injury. Firstly it is the workplace environment itself, the use of equipment, and lastly human behaviour in experience and skill.

assess the impact of increased understanding of the structure and function of the human body on increased awareness of safety in the workplace and the home

The more we understand the body the more aware we become of injuries associated to it. For example: The understanding of the spine and its mechanics shows us the strain given repeatedly (RSI). It then allows people to take acts accordingly.

2. Potential risks to the respiratory system can be minimised by implementing protective measures

The respiratory system allows the absorption of oxygen and the expulsion of carbon dioxide.

account for the moist lining of the lungs in terms of the need to dissolve oxygen so it can diffuse through to the blood

The lungs have to be moist to allow the dissolved oxygen to diffuse to oxygen deficient blood. The lungs must have a large surface area which is provided by bronchiole and alveoli in which the blood must pass through before it can be diffused with oxygen and then to the blood. The oxygen must dissolve in water first which is why it is necessary for a moist lining in the lungs.

outline the purpose of mucous production and the role of cilia on epithelial tissue in the lungs

Mucous is produced to trap any invading particles not desired. The hair-like cilia is lined in the lungs which act to trap and move out the trapped particles up the throat.

outline the effect of chronic exposure to inhaled solids on lung tissue

Prolonged exposure of substances can increase disease and make the lung tissue less effective.Ash – caught in the lining of bronchiolesCarbon monoxide – reduces ability to diffuse oxygen

identify safety procedures and equipment in the school and workplace

Fume cupboards – isolate potentially hazardous fumesFiltering masks – filter fumes, dust and gases. Dust extractors – to redirect the dust to another locationVentilation – to allow the air to exchange effectively

3. The structure of the eye and its function dictate that eyes must be protected from foreign materials, intense light and deformation

The eye allows humans to see through the taking in of light and image and translating it to the brain.

outline the function and structure of the eye

Structure FunctionConjunctiva Membrane which covers and protects corneaCornea Transparent circular segment which light enters through and

is initially focused in centre of eyeSclera The white of the eye which protects and nourishesRetina Back of the eye which converts light to nerve impulses made

up of photoreceptors which allow shape, movement and colour. Rods are for low light and cones (three) are for colour RGB

Tear ducts Produce tears which protect the eyeEyelids Physical protection in front of eye – protective measureIris Coloured part of eye which is a muscle for the opening of the

pupilConvex lens Behind iris, which focuses light to the retinaMuscle in eye Eye is controlled by 3 muscles – up+down, left+right,

diagonal movement

identify that the eye produces tears as a protective mechanism

Tears are produced in reaction to protect the eye. It contains water, salts, a lubricant and antibacterial agent.

assess the need for eye exercises in many work situations

The eye must be exercised to maintain its movement. In many work situations, the eye is made to rest for long periods of time and hence tiring it.

explain first aid procedures when substances are splashed into the eye

The eye must be splashed with water continuously for 20 minutes when the eye is affected by substances being splashed in the eyes.

discuss why light emitted naturally or by some technological devices may be a cause for concern

The eye is very sensitive to light, and high amounts of light can focus large amounts of light into the retina.

- A solar eclipse might filter out the sun but the energy still penetrates the eye- Technologies such as welding light, laser light and high-intensity light also have high

concentrations of light.

outline the structure and discuss how the composition of one type of specialised protective glasses is designed to protect the eye and sight

Sunglasses are an effective way to filter out much of the UV light. The glasses are produced with a lens that is darker in colour, aimed to absorb and filter much of the heavy white light.

4. Earmuffs and ear plugs can reduce damage by sounds in the environment

The ear is an organ that lets humans hear sounds. The ear works by picking up the vibrations of sound and transporting it until it eventually is translated to the brain.

describe the structures of the ear and identify potential causes of hearing impairment

It is structured as:Pinna (flap): gathers sound waves and funnels into ear passageEardrum (tympanic membrane): Vibrates with sounds to the middle earEar ossicles: three bones: hammer, anvil and stirrup which transmit sound to inner earCochlea: the snail like structure which has hair and receptors to carry sound signals to the nerve.Auditory nerve: carries signals to the brainEustachian tube: balance

Potential causes for hearing impairment are ageing and exposure to loud sound.

outline the causes of ‘industrial deafness’ and relate this to the structure and function of the ear

Industrial deafness is the loss of hearing through the exposure of noise. It cannot be reversed.

When loud noises are exposed over a long period of time, the cochlea is damaged. The cochlea has millions of tiny hair which carry sound signals along to the auditory never. When loud sounds are heard for a long time, the tiny hairs stiffen and die causing less transmission of signals.

discuss sensory fatigue and the associated problems of hearing in noisy environments

Sensory fatigue is achieved when the ear is overworked through the prolonged exposure of noise. The brain must concentrate higher in lower sounds which make it harder to hear in noisy and even quieter environments.

explain how the structure of earmuffs and ear plugs reduces sound energy reaching the auditory canal

Ear protection reduces the amount of energy passing through the auditory canal.

Earplugs are made out of foam and they are inserted into the ear canal. The foam absorbs some of the sound waves and reduces the transmission of lower frequencies.Earmuffs are designed to cover the whole ear and cancel much of the outside sound. It is useful in filtration of higher frequencies.

5. While the soft tissue of the brain is protected by the bones of the skull, it can require further protection in certain situations

The brain is a very important part of the body, and the skull protects the brain from any impact and injury. However, rapid movement and force can cause injury to the head and brain.

identify the role of the skull in protecting the brain

The skull has the role to protect the brain as it is a soft and important part of the body

define the term concussion

A concussion is a sudden direct blow to the head, causing the brain to go in shock

describe the effects of bruising of brain tissue and blood vessels

The bruising of the brain tissue and blood vessels cause the blood to be released inside the brain and swell and crush surrounding tissue.

discuss the energy transfers and transformations involved when a hard hat or helmet protects the head from injury

A hard hat or helmet is designed to absorb and reduce shock delivered to the head. When energy is suddenly delivered, the force is absorbed through compression.

discuss the relationship between the design and use of hard hats and safety helmets in areas of building construction and sport

Helmets and hard hats are designed to minimise the impact on the head and they must be used where necessary. It limits the force exerted on the skull by spreading the force and scatter energy as much as possible.

describe situations in which hard hats and safety helmets are used

Construction areas have falling objects, which is why hard hats must be equipped with in case of injury. Safety helmets are widely used in sporting, where there is a high chance of sudden impact.

6. Injury to the integrated system of muscles, joints and bones that allows movement of the human body can be reduced by using safe work practicesThe skeleton along with muscles allows us to move, and the injuries to these can affect our movability.

describe the relationship between the axial skeleton, synovial joints and muscles

The axial skeleton is the central point including the skull, the backbone (vertebral column), breastbone (sternum) and the ribs.

Joints have to occur in order for movement in the body. The most common joint is a synovial joint which allows a large range of movements. They are enclosed by a synovial membrane which lubricates the joint.Muscles are for movement of the joints which join to two bone and act in pairs. One muscle contracts while the other expands and vice versa. The axial skeleton acts as a base and the joints acts as movement while the muscle act as catalyst for the movement. All three are required for movement.

describe the role of ligaments, tendons and cartilage in joint movement

The joint must keep moving, and for this to happen cartilage is found at the end of each bone to act as a cushion, shock absorber and friction reducer. The bones at a joint are held together by flexible fibres called ligaments. Ligaments keep the bone in place and in its ability. Tendons are the attachments of muscles to the bone which then can provide the movement to occur.

outline the causes of, and preventative measures used to deal with, repetitive strain injury

Repetitive strain injury (RSI) is caused by excessive work rate rapid and repetitive movements stressful postures

There are many things that can be done to reduce and avoid RSI: reduce unnecessary stretching use proper equipment have breaks

analyse safe lifting practices, relative to the muscles used, to minimise injury

Lifting must be performed with minimal weight given to the backbone. Muscles in legs and arms should be used instead of muscles at the back.