Ageing and medical technologies

HBS3B

Revision questions

Draw a spinal reflex arcExplain the importance of spinal reflex arcs

Revision questions

Explain the importance of spinal reflex arcsThey allow rapid response to harmful eventsUsually movement out of danger is initiated before the message about the danger reaches the

brain.

Draw a spinal reflex arc

Life expectancy

People today have a longer life expectancy than ever before. Men can expect to live to 78 and woman to 82. This means that an increasing proportion of our population is considered to be “aged”.

This has a number of implications for our society including increased number of retirees, increased need for financial support and health care for the aged. Increased need for hospitals, aged care services eg nursing homes, retirement homes, hospices, etc

Effects of ageing 1Ageing or senescence affects all our body systems. Some of the effects of

ageing include:Skin and hairWith age skin generally becomes thinner. Hair becomes white or grey and skin

may show colour spots because cells producing pigment become less active. Baldness may occur in men and women and sweat glands become less active.

Muscles, bones and jointsThere is a decrease in cell size, numbers and fibre in the muscles, causing them

to lose mass and strength.Bones become lighter and more brittle because calcium leaches out (especially

in females due to low oestrogen, and in smokers). This makes people more susceptible to fractures.

Joints become less flexible and arthritis occurs because of wear and tear on the joints

There are changes in posture, and height decreases, because of osteoporosis, joint damage and muscle wastage.

Digestive systemTeeth fall out and muscles of the jaw become weaker. Digestive glands slow

down, and digestion becomes slower.The smooth muscles in the digestive tract work less efficiently as they weaken

therefore causing problems such as constipation and indigestion.

Effects of ageing 2

Circulatory systemThe efficiency of the heart and circulation decreases with age. The pumping of

the heart decreases with age, and less blood is pumped because the mass and strength of the heart is reduced. Blood flow to tissues decreases because of reduced efficiency of the heart and narrowing of arteries.

Blood pressure tends to rise, and there is a greater risk of cardiovascular disease.

Bruises become more common because of thinner walls to capillaries and thinner skin.

Respiratory systemWith age breathing efficiency is decreased. This is a result of decreased

elasticity in the lungs and reduced strength of respiratory muscles. Gas exchange in the lungs is reduced.

The result of this decreased breathing efficiency on the heart is put under further pressure.

Effects of ageing 3Brain, nerves and sensesOverall the functioning of the nervous system decreasesThere is a decrease of total brain cells and their fibres during ageing. This results in loss of

memory and some co-ordination.There is a certain amount of sensory loss with age.Sounds are lost in the low frequency range. The tone and sense of words become difficult

to hear.Vision becomes less acute. Generally speaking, people tend to need glasses for close work

eg reading. Along with this, night vision grows weaker.Smell and taste senses decrease and balance becomes less reliable.Touch becomes less acute as does pain, pressure and heat and cold perception. As a

result of this some injuries such as falls are more common.

Endocrine systemMany glands decrease their activities and secretions. In particular, the ovaries in females

cease secreting oestrogen and progesterone. This is associated with the cessation of ovulation and is called menopause. The lack of the sex hormones can lead to osteoporosis and hormonal imbalances

Males have a reduction in testosterone production with a decrease in sexual drives.The reduced activity of the thyroid gland, coupled with the loss of body mass and circulatory

changes means that older people are more susceptible to temperature changes. Many older people may become diabetic, and need to change their diets and/or exercise

regimes to deal with this.

Effects of ageing 4

Excretory systemKidney function changes in old age because of wear and tear, causing

breakdown of the filtering units. One outcome of this is an increase in urinary problems eg kidney failure.

Immune systemThe thinness of the skin and slowing down of glands means that it is

easier for germs to enter the body. Once entered the body, these germs are less likely to be destroyed, as the immune system is less effective. Thus older people are at greater risk of diseases such as colds and flu.

People appear to age at different rates. Some people appear old and decrepit in their fifties, while others are active into their nineties. Research suggests that lifestyle has a big impact on the ageing process.

Effects of ageing 5

From this it can be seen that the elderly need access to treatments or devices that help them compensate for the changes occurring in their bodies eg mobility aids, prostheses (eg glasses, hearing aids, false teeth, bionic ears, artificial joints), pacemakers, medical treatments (eg insulin, anti-inflammatories) and dietary supplements.

Some behaviours or dysfunctions that were once considered due to old age are now recognised as symptoms of disease, some of which can be treated or prevented.

In order to increase the chances of a healthy old age we should have a healthy lifestyle when young – eg healthy diet, regular exercise, don’t smoke, reduce alcohol, etc, and continue this as you age – particularly exercise. As we get older we should keep physically and mentally active and continue to socialise.

Diseases of old age 1 - Arthritis

Arthritis is inflammation of a joint or joints.There are several types, including rheumatoid, osteoarthritis and gout.Factors that increase the risk of arthritis include diet, exercise, obesity, age,

damage or injury due to over use (eg sport)

Symptoms of arthritis include:Rheumatoid: severe form involving inflammation, swelling, pain and loss of

function of joints. It starts with inflammation of the synovial membrane, which grows to form abnormal tissue called pannus. This pannus grows over the articular cartilage, destroying it, and fills up the cavity, thus restricting movement of the joint.

Osteoarthritis: degenerative disease due to wear and tear on the joints. The articular cartilage deteriorates, and bony growths develop in the joints, thus decreasing mobility, and causing pain.

Gout: inherited genetic disorder causing an accumulation of sodium urate crystal in the joints, thus causing pain, swelling and eventual destruction of joint tissues.

Treatment for arthritis include: drugs – painkiller, steroid, anti-inflammatory, physiotherapy, diet & exercise regimes, joint replacement surgery (in severe cases)

Diseases of old age 2 - OsteoporosisOsteoporosis is a reduction in bone mass leading to bone weakness

and increased risk of fractures. It is seen more often in females than males due to the hormonal changes seen in menopause.

Factors that increase the risk of osteoporosis include age, low calcium or vitamin D levels, lowered oestrogen levels (especially seen after menopause in women and in smokers), smoking, lack of exercise

Symptoms include: thinner bones, more fractures, ‘dowagers hump’ and decreased height (due to collapsed vertebrae in upper spine)

Treatments include: increased dietary calcium and vitamin D supplements (these have most impact in younger people – so its important to start building bone mass young) and weight bearing exercise

Diseases of old age 3 – Alzheimer’sAlzheimer’s disease is an irreversible, progressive brain disease that

slowly destroys memory and thinking skills, and eventually even the ability to carry out the simplest tasks. In most people with Alzheimer’s, symptoms first appear after age 60.

Alzheimer’s disease is the most common cause of dementia among older people.

Dementia is the loss of cognitive functioning -thinking, remembering, and reasoning - to such an extent that it interferes with a person’s daily life and activities

Although we still don’t know what starts the Alzheimer’s disease process, we do know that damage to the brain begins as many as 10 to 20 years before any problems are evident.

Tangles begin to develop deep in the brain, in an area called the entorhinal cortex, and plaques form in other areas. As more and more plaques and tangles form in particular brain areas, healthy neurons begin to work less efficiently. Then, they lose their ability to function and communicate with each other, and eventually they die.

This damaging process spreads to a nearby structure, called the hippocampus, which is essential in forming memories. As the death of neurons increases, affected brain regions begin to shrink. By the final stage of Alzheimer’s, damage is widespread and brain tissue has shrunk significantly.

Factors that increase the risk of Alzheimer’s include genetic, environmental, and lifestyle factors.

Diseases of old age 3 – Alzheimer’s 2Symptoms include: memory loss, often followed by confusion,

mood swings, aggression and general withdrawal but can vary depending on the degree of damage suffered

Mild Alzheimer’s DiseaseAs Alzheimer’s disease progresses, memory loss continues

and changes in other cognitive abilities appear. Problems can include getting lost, trouble handling money and paying bills, repeating questions, taking longer to complete normal daily tasks, poor judgment, and small mood and personality changes. People often are diagnosed in this stage.

Moderate Alzheimer’s DiseaseIn this stage, damage occurs in areas of the brain that control

language, reasoning, sensory processing, and conscious thought. Memory loss and confusion increase, and people begin to have problems recognizing family and friends. They may be unable to learn new things, carry out tasks that involve multiple steps (such as getting dressed), or cope with new situations. They may have hallucinations, delusions, and paranoia, and may behave impulsively.

Severe Alzheimer’s Disease By the final stage, plaques and tangles have spread throughout

the brain and brain tissue has shrunk significantly. People with severe Alzheimer’s cannot communicate and are completely dependent on others for their care. Near the end, the person may be in bed most or all of the time as the body shuts down.

Diseases of old age 3 – Alzheimer’s 3Treatments include a number of strategies - including

helping people maintain mental function; managing behavioral symptoms; and slowing, delaying, or preventing the disease.

A nutritious diet, physical activity, social engagement, and mentally stimulating pursuits can all help people stay healthy.

New research suggests the possibility that these factors also might help to reduce the risk of cognitive decline and Alzheimer’s disease.

Scientists are investigating associations between cognitive decline and vascular and metabolic conditions such as heart disease, stroke, high blood pressure, diabetes, and obesity.

Understanding these relationships and testing them in clinical trials will help us understand whether reducing risk factors for these diseases may help with Alzheimer’s as well.

Diseases of old age 4 – Parkinson’s

Parkinson’s disease is a degenerative disorder of the brain for which the cause is not known.

A section called the substantia nigra (which is responsible for making the neurotransmitter dopamine) becomes severely depleted of dopamine and so the pathways responsible for coordinating body movements (including the basal ganglia, the substantia nigra and the cerebellum) become disrupted causing the abnormality of movement.

The symptoms gradually get worse over time

Factors that increase the risk of Parkinson’s include family history and exposure to environmental toxins

Diseases of old age 4 – Parkinsons’s 2Symptoms include abnormalities of movement,

involving one or more of the followingTremor - an involuntary rhythmic shaking in an

extremity (like an arm or leg), or in the face. A Parkinson's tremor is worst at rest and gets better when the extremity is moved; it often disappears during sleep. In the hand, the thumb may move back and forth against the other fingers – Parkinson called this motion 'pill rolling'.

Bradykinesia - slowness of movement. People with bradykinesia seem to freeze: they have trouble initiating movements and they're slow in changing position. Their voice also sounds monotonous, and they have a fixed, staring, unblinking expression. They stoop, and when they walk they shuffle.

Muscular rigidity - muscles – especially in the arms, shoulders and neck – become stiff, rigid, and resistant to being passively moved. They may move in a series of ratchet-like steps: this is called 'cogwheel rigidity'.

Treatments include drugs to increase dopamine levels, and modification to the household to help sufferers cope.

Quality of life and euthanasiaSome people suffer from diseases for which there is no hope of recovery, and in

which their quality of life is so poor they wish to end their life.Quality of life refers to a person’s enjoyment of life and includes factors like

mobility, pain and ability to participate in desired activities.

Euthanasia refers to is the bringing about of the death of a person (usually because of severe pain or suffering due to a terminal illness).

Some issues relating to euthanasia include: At present it is illegal to perform, or aid people to perform euthanasia (assisted

suicides) as it is considered a crime (either murder or suicide). Suicide still carries a criminal penalty for those who are unsuccessful. The Northern Territory did bring in a bill to enable euthanasia of the terminally ill,

but that was overturned by the federal government. It is acceptable to with hold medical support (eg life support machines), where

patients, or family, have given consent, and thus allow a person to die naturally.

In the traditional beliefs of the Christian, Jewish and Muslim religions, the taking of another’s life is considered wrong.

The euthanasia issue raises some moral problems as well - there is a fear that it could be misused against a section of the community (eg Hitler’s program to wipe out the Jews), or against elderly/ill people who have no ability to choose.

Arguments for and against euthanasia

Arguments for voluntary euthanasia include

• Choice is a fundamental right

• Only a patient can decide whether their suffering is too great

• Patients are shown more respect when they can choose to die

• There is a large financial and resource burden in keeping a seriously ill person alive

Arguments against voluntary euthanasia include

• Human life is sacred – no-one has the right to end life

• It puts doctors and other health care workers in a position where they have to go against their training (and possibly beliefs)

• Patients may not be competent to make the decision

• There may be a cure in the future

• There may be pressure to end life for convenience or financial reasons

• Euthanasia may fail and cause further suffering

Biomedical technologyBiomedical technology refers to devices and machines used in the medical diagnosis or

treatment of injuries or disease. These can be mechanical eg prosthetic limbs, bionic devices, external eg supports, bionic limbsinternal eg artificial joints, bionic ear

Some specific examples include:Devices to increase mobility or treat disorders of the musculoskeletal systems eg mobility aids,

artificial limbs, artificial jointsDevices to aid deficiencies of hearing or vision eg glasses, hearing aids, bionic ears and eyesDevices to treat cardiovascular disease eg pacemakers, artificial valves, transplants (heart or

valve)Dietary supplements or fortified foods eg vitamins, fish oils, added nutrients in some foods (eg

thiamine, vitamin D or folic acid), fluoridation of waterPharmaceuticals and drug delivery systems eg analgesics, anti-inflammatories, statins,

antibiotics, insulin, tablets, patches pumps and implantsBiological technologies eg tissue regeneration, spray on skin, transplants, grafts, stem cell

therapyPhysiotherapy involves manual therapies (eg massage, stretching manipulation), use of

technologies (eg diathermy, ultrasound, laser or transcutaneous electrical nerve stimulation -TENS) and other procedures (eg splinting, strapping) and can be used to reduce pain, restore muscle strength and increase mobility

Bionic devices are electromechanical devices used to replace dysfunctional body partsExamples include limbs, ear (cochlear implant) and eye (still being developed)