Atrophy

It is an acquired condition and is defined as diminution in size of organ due to decreased in number of cells , size of the cells without any degenerative change and little amount of replacement by fibrosis .

    There are two types of atrophy

  1.. General atrophy –

a)      Senileatrophy -  This is a physiological atrophy . there will be atrophy of different organs and tissue like endocrine glands , sex organ , bones , muscle ., skin during sensility . Atrophy of breast and uterus in female take place at the age of menopause . In long continued wasting disease and in old age , the heart becomes a smaller in size , myocardium is slightly thinned out and nutmeg brown in appearance . Microscopically , the myocardial fibres show accumulation of small fat globules and lipochrome granules which are called wear and tear pigment . Such type of atrophy is called  Brown atrophy of heart .

b)      Starvation atrophy – This type of atrophy  is found in famine , carcinoma of oesophagus , anorexia , nervosa , attended with loss of appetite etc . In these condition , less nutrition is the main cause and there will be utilization of stored sources of energy metabolism like carbohydrate . fat , protein . Cachexia or generalized wasting is seen in tuberculosis or carcinoma due to malnutrition .

2… localized atrophy or pathological atrophy ----

i)                    Ischaemic atrophy –there will be atrophy of the affected part due to diminution of blood supply .

ii)                  Pressure atrophy – There will be atrophy of individual cells due to persistan t pressyure of some substance like intercellular infiltration of amyloid , glycogen or due to pressure of tumour .

iii)                Disuse atrophy – This ty,pe of atrophy is seen due to the restriction of the use of a part followed by diminished metabolic activity . This is particularly observed in the muscle fibres . Whre there is immobility of the limbs as in ankylosis of a joint or hemiplegia .

iv)                Neurophagic atrophy – This is due to destruction of neuromuscular activity where the nutruition  of tissue is not properly maintained as a result there will be presence of feature of atrophy as found in poliomyelitis , tabes dorsalis , syringomyelia , facial herniatrophy , lower motor neurone paralysis etc .

v)                  Endocrine atrophy – If pituitary gand destroyed the dependent endocrine glands like adrenal gland , thyroid gland and gonads may undergo atrophy as this trophgic harmonic stimulation diminishes .

vi)                Atrophy due to over work – Proper nutrition and over work may lead to the hypertrophied condition of muscle but less nutrition and over work will produce atrophy of the muscle .