Very Short Essay on Ageing !
Ageing also called senescence may be defined as the progressive deterioration in structure and function of the body cells, tissues, organs and organ systems of the organism with the advancing age. Gerontology/Geriatrics is the branch of biology that deals with the study of the process of ageing.
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Changes with age
1. Morphological Changes:
(a) Thin, shrivelled and stooping body,
(b) Dry and wrinkled skin,
(c) Brittle bones
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(d) Gradual stiffening of lens so as to reduce accomodation.
2. Physiological Changes:
(a) The decrease in the efficiency of heart to pump blood
(b) Less formation of blood cells by bone marrow.
(c) Decrease in the supply of the blood to the lungs, brain and kidney.
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(d) Gradual loss of capacity to retain water by the cells and tissues.
(e) Reduction in the number of kidney tubules and taste buds
(f) Decrease in the formation of urine
(g) Impaired hearing and sight.
(h) The body’s immune system loses its ability to effectively deal with the antigens. This reduces the resistance to infectious diseases.
3. Cellular Changes:
(a) Increased number of chromosomal aberrations in the liver cells. In the liver cells of mice, the enzyme aldolase has been recorded to become more and more inactive with advancing age along with glucose-6 phosphate dehydrogenase
(b) The increased defects in the DNA structure produce greater amounts of defective proteins in the body cells
(c) Increased accumulation of pigments in body cells especially in the brain tissue and muscles. According to some experts, these pigments are the worn out cell organelles like mitochondria
(d) Decreased power of multiplication, in cells, though it differs in various tissues
(e) Reduced water retentivity.
(f) Calcium deposition in cell membranes.
(g) Changes in cellular enzymes
(h) Quantity of effective protein increases
(i) Decrease in mitochondria and increase in lysosomes.
4. Extracellular Changes:
(a) Extracellular changes include structural and functional changes in collagen which makes up about 40% of the total protein in the body
(b) Collagen becomes less permeable, rigid and insoluble and thus interferes with exchange of materials through surrounding cells
(c) With changes in collagen, oxygen and nutrients do not diffuse easily into the cells.
(d) Diffusion of materials in and out of the cells is greatly obstructed. All these changes hamper the activity of the cells and hence the vital organs with ageing.