Ageing

Life span

Maximum number of years a member of a species could hope to live, in humans this is 120

Life expectancy

Average number of years we are likely to live for, depends on the culture about 70 in the UK.

Factors in longevity

The rates at which individuals seem to age varies.

Gender, (about 7 years in the UK)

Environmental conditions

Diseases of civilisation

Genetic predisposition to disease

Genetics, MZ twins die an average of 37 months apart, DZ twins an average of 78 months apart.

Seems to run in families

Diet, mostly as it causes specific pathologies

Theories of ageing

Limited number of cell divisions

Cells from older people will divide fewer times in culture than cells from younger people.

In addition there is loss of irreplaceable cells, eg neurones

Genetic error

Accumulated damage to the DNA throughout life is ultimately enough to prevent successful mitosis. There may also be production of unsound cells

Immunological

As we age the immune system loses the ability to differentiate between self and non-self so the immune system starts to destroy the tissues of the body. It is true that auto immune disease is more common with advancing age.

Waste accumulation

The accumulation of waste products in cells eventually prevents their function. This may be particularly important in cells which do not divide such as neurones and muscle cells.

Collagen deterioration

Found in connective tissue as white fibres. It forms cross bonds with age so loses its elasticity, eg lungs become less elastic with age and skin becomes wrinkled.

Progeria

This condition demonstrates accelerated ageing, with loss of scalp hair, loss of subcutaneous fat, dry wrinkled skin, periarticular fibrosis and generalised atherosclerosis. Death from "old age" usually occurs in the teens.

Multi theory theory

Ageing occurs as a combination of many different factors.

Disease in old age

Multi-system failure, senile multiple pathology

Changes with age

Senescence or senile

Senescence - normal change of mind and body with increasing age, typical age related changes include, postural change, dentures, wrinkles, baldness, grey hair

Senile - senescence complicated by morbid processes of degeneration

Hair

With age hair forming cells in the hair follicles die, leading to hair loss in both genders.

Hair also starts to grow in new places, eg. hairy ears in men and female facial hair, due to oestrogen loss.

Skin

Connective tissues stiffen due to loss of elasticity. Epidermal germative layer mitotic rates are reduced so wound healing is slowed. Nails thicken and less sweat is produced.

Cardiovascular system

Some myocardial muscle mass is replaced by fibrous tissue

There is age related thickening of the tunica intima

A degree of atheresclerosis is common

Loss of elasticity in the arterial tree leads to rise in systolic blood pressure

Respiratory system

Loss of elasticity of the alveoli

Reduced area for gaseous exchange

Reduction in chest wall mobility may reduce vital capacity and peak flow

Neuromuscular system

At 75 years a man may be 3 inches shorter than as a young adult.

Collagen stiffens ----- ligaments and tendons are more rigid ------ reduced joint mobility ---- stooped posture.

Intervertebral disk compression.

Other factors may include arthritis, muscle atrophy, and osteoporosis.

Exercise and the fitness gap.

In June 1996 Jos Naylor ran up and down 60 Lakeland fells in 36 hours to celebrate his 60th birthday, (the fitness gap).

Lack of activity predisposes to weight gain.

Half an hour five times per week.

"Rest equals rust"

Advantages include, physical fitness, social interactions in activities, weight control, heat production, increased metabolic rate, improved muscle tone, increased cardiac efficiency, improved appetite, improved bowel function, increased confidence, improved immune response, raised HDLs, improved lung capacity, improved circulation of the blood.

Strength, supplety, stamina.

Neurological system

Brain

Neurones cannot divide

Learning

Old people retain the ability to learn, maybe it is sometimes slower due to lack of practice.

There are thousands of retired Open University graduates.

Memory for recent events tends to go first, possible due to loss of cortical neurotransmitters.

Deficits in cortical function may be offset by accumulated experience.

Dementia

A progressive irreversible impairment of intellectual function.

About 10% of those aged 65 and over.

Alzheimer's disease.

Loss of memory for recent events

Sleep

Less sleep seems to be required as we age.

Sleep disturbance may be associated with abnormal serotonin activity.

The sense organs

Taste and smell

Loss of neurones in the olfactory centre

Loss of sensory cells in nasal passages

Reduced number of taste buds

Less saliva.

Tactility

Changes in pain receptors raises pain threshold, probably due to changes in the nocioceptors.

Raised touch threshold.

Consequent increased risk of pressure sores.

Vision

Intra and extraoccular changes.

Eyelids may droop caused by loss of muscle tone, (senile ptosis).

Reduced reabsorption of tears, so eyes may water, despite reduced tear production.

Decreased neurones in optic cortex and optic nerve.

Retinal changes may diminish visual fields.

Astigmatism may occur due to changes in the curve of the cornea.

Senile miosis, (reduced aperture of the lens) may occur due to changes in the pupillary muscles.

Increased glare sensitivity due to increased light scattering by lens and cornea.

Glaucoma may occur due to less efficient drainage of the aqueous humour.

Lens may flatten causing presbyopia, (difficult focusing on near objects).

Increased incidence of lens opacity due to ultra-violet exposure.

Hearing

External auditory meatus plugged

Eardrum punctured or scarred by infection

Ossicles may be partly fused.

Cochlea degeneration, made worse by occupational exposure.

Digestive system

Dentition

Bone reabsorption from maxilla leads to loose teeth

Gums may reduce contributing to tooth loss.

Gastrointestinal tract

Volumes of saliva reduced and activity of salivary amylase reduced.

Slowed rates of peristalsis in the oesophagus.

Atrophy of gastric mucosa may lead to gastritis and vitamin B12 lack.

Reduced amount of gastric secretions.

Reduced absorption from small intestine.

Reduced muscle tone in the colon may lead to constipation.

Liver

Cell loss may lead to decreased rates of detoxification, eg alcohol.

Urinary system

Loss of renal mass

Bladder capacity lowers and residual volume increases

Prostate may enlarge

Stress incontinence in females

Endocrine system

Most glands maintain levels of hormone secretion.

Thymus gland activity reduces through adult life.

Oestrogen falls after the menopause.

Testosterone production gradually falls.

Sexuality

Sexuality and sexual activity may continue to death

Sometimes male libido decreases with age, but often female libido increases.01233.

Immunity

There may be slowed maturation of T lymphocytes due to reduced thymus gland activity

Thermoregulation

In ageing

Cerebral cortex may be atrophied reducing perception of heat and cold, more so in dementia.

Less active reflexes stimulating vasoconstriction and shivering

Reduced ability to sweat.

Reduced mobility therefore less heat produced.

Appetite loss causes lowered metabolic rate.

Hypothyroidism more common in elderly

Remember "normal" may be as low as 35`C

Hypothermia

Less than 35`c

Drowsiness, confusion, cyanosis, pallor, loss of consciousness, they feel cold, bradycardia, loss of shivering activity.

Increase temperature by 0.5-1`C per hour

If they are warmed to quickly there is too much blood flow to the skin, this may reduce venous return to the heart.

Record rectal temperature.

Record pulse and blood pressure regularly.

Nurse sitting up as there is an increased risk of pneumonia.

Screening

There are many unreported findings in the elderly, some of which are treatable.

Depression Deafness Chronic bronchitis Food defects Hip disease Anaemia

Dementia Blindness Anxiety states Cardiac failure Diabetes mellitus Hypothyroidism Osteomalacia Faecal impaction