Preksha Dhyana Human Body Part 2

Author(s): Jethalal S Zaveri
Publisher: Jain Vishva Bharati

Page 87

of appetite. The sedentary adult, thus, takes in more calories than the body can use up and the excess is stored as fat1. A careful programme of exercise and diet only can stop the weight-increase.
Aging
Aging or senescence is a biological process characterized by a gradual deterioration of the structures and functions of the body, resulting in an increased susceptibility to accident and disease. No sooner has maturity been reached than a progressive decline in the body's efficiency begins. Different organs and tissues age at different rates. Nerve and musclecells show an earlier decline in the functional capabilities than tissues such as those of liver and pancreas, in which active cell-divisions continue longer.
Some of the most tragic changes are observed in the central nervous system. A combination of loss of nerve cells, which are not replaced, a slowing of the nerve-conduction and reduction of circulation to the brain results in a progressive decline of mental efficiency. The sense of the aging person become less acute. There is a progressive hearing loss. The eyes become prone to various degenerative diseases and a reduction of the ability of the eye muscles to accommodate the lens results in hypermetropia i.e. farsightedness. Taste is also dulled as taste-buds are progressively lost. A lengthening of reaction time and growing lapses of memory become apparent. Learning is more difficult for older people, partly because of the reduced mental efficiency and partly because of interference from previously acquired knowledge.
Various degenerative changes occur in the circulatory system. The heart-muscle may be partially replaced by fribrous or fatty material. Deterioration of the elastic fibres stiffen the artery-walls and calcified fatty deposits within them may weaken them so that they burst when the bloodpressure is raised by emotion or straining or may lead to circulation-blocking blood-clots.
1. "Fat" and "fifty" are often together.
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