PHYSIOLOGY OF AGEING
Gerontology is a multidisciplinary study of old age from various points of view. biological, medical, sociological and economical. It is an important branch of medicine in developed countries where old people are left uncared by their sons and daughters. In India. the aged people are well taken care of, under the joint family system. But with the fast developing industrialization and urbanisation, individualistic tendency, is replacing the joint family system. Under the present conditions of economical unstability, this phase of life is proving harder day by day. Thus, old age is the period when medical assistance is most needed and yet least provided for.
Physiological changes due to ageing:
At celluar level, there may be gene mutations in somatic cells or some harmful substances are produced that decrease the vitality of the organism or some organ systems. The granules in the cell cytoplasm become finer and finally disappear. Nuclei become more compact and tiny. DNA, RNA and ATP, the symbols of continued vigour and activity of cells, decrease. Nuclei show cavitation and the metabolic decline.
Skin and appearance:
Skin suffers and betrays changes due to age. People show obvious wrinkles on their face after 50-60 years. The skin develops deep pigmented spots. Moles and talangiectasis may also be noticed in many cases. The hair become grey in old people and some do become bald. Elasticity of the skin is on the whole decreased and nails become pale and brittle. Wounds don't heal quickly and often there is vitamin deficiency signs.
Joints and Bone:
Bones loose calcium and break easily. Osteoporosis may develop. The cartilages become hard and osteoarthritis develop in many cases, affecting locomotion. This may lead to old age falls, fractures and haemorrhages. In old, weight of the body is reduced due to loss of tissue and general weakness may develop as age advances above 60 years.
Digestive system and Nutrition:
Body temperature decreases and old persons complain of cold and may shiver. The calorific needs are decreased. Liver and alimentary tract produce less digestive juices. Appetite, digestion and absorption become poor. Teeth are lost in 40% of the persons above 60 years.
Cardiovascular changes:
Major are seen in cardiovascular system. There is a gradual transition from the low and safe side blood pressure to a high and dangerous side. Arteries become thick and atherosclerotic. There is shrinkage of blood supply to various organs and the performance of various organs become poorer. The heart cannot keep up its efficient circulation during work and exercise. There is increased rigidity of the heart valves, thickening and roughening of auricular endocardium and atrophy of the special protion of the left ventricle. Cardiovascular diseases are found in approximately 60% of the old patients.
Respiratory system:
Functions of respiratory system also get poorer. Lungs do not fill up well. Vital capacity decreases. Breathlessness is the cry of the respiratory centre for want of oxygen. There is marked susceptibility to respiratory infections.
Nervous system:
In the central nervous system, total brain weight is decreased by one sixth or more in the aged. There is convolutional atrophy which is more conspicuous in the frontal lobes, where the neurons are assigned the most complex thought processes. There is a decrease in the vascular supply to brain, as a result memory, behaviour and judgement are altered and various types of paralysis may develop.
In the aged person input and output are tightly coupled. Thus, an error made once or twice during the process of learning a new skill, becomes difficult to eliminate. Old persons need continuous reassurance and information as they proceed to perform a task.
In general, the ability to cope up with life deteriorates with age. Apparently, the reason is that with experience, wisdom continues to grow but speed, memory, learning ability and simple reasoning fade. There is a loss of memory for recent events in the elderly while their memory for past events remain crystal clear.
Special senses degenerate in the old. Eye vision is affected; cataract and glaucoma may develop. Hearing is adversely affected. Tastes of the tongue degenerate.
Urinogenital system:
Renal functions in general are decreased. Increased frequency of micturition is the common complain of old people. Probably about 50% of the nephron units are lost in people over the age of 60 years.
The active reproductive period, in women continues up to 40 years-at the most to 50 years of age. Climacteric in women is comparatively an abrupt and earlier phase, while in man the process is much prolonged. Prostatic hypertrophy in man is a frequent occerrence in men who have passed middle age.
Endocrinal atrophy leads to all types of metabolic and other types of degenerations. Genital hormones strength, vitality and weight are decreased and there is easy fatigue and loss of interest in life.
Infants of elderly parents are more likely to have congenital defects than the children of young parents.
Aged persons are more prone to cancer, diabetes mellitus, high blood pressure, and arterio-atherosclerosis leading to heart, kidney and brain diseases following ischaemia, i.e. decrease in blood supply. Old age terminates in death which is the end point of titration of life.
