Causes of Atrophy and Hypertrophy

Non-neoplasia. A: Normal cells, B: Atrophy, C: Hyperplasia, D: Hypertrophy, E: Metaplasia and F: Dysplasia. Hematoxylin eosino staining. (Photo credit: Wikipedia)

What is Atrophy?

Atrophy is a type of cellular adaptation. It is generally a reversible process.

• Atrophy is a decrease in the size of a cell or tissue.
• The decreased size of a cell or tissue results in decreased oxygen consumption.
• The metabolic needs of the cells get reduced.
• The overall efficiency of the cell function gets increased.
• Atrophy is irreversible if it is caused by nervous innervation of the tissues.

Causes of Atrophy:

• Prolonged bed rest
• Disuse of limbs
• Disuse of tissues
• Poor nutrition of the tissues
• Ischemia

What is Hypertrophy?

Hypertrophy is a kind of cellular adaptation in response to the changes in the surrounding fluid environment, when the cells are exposed to the numerous stimuli.

• In hypertrophy, there will be an increase in the cell size.
• Tissue mass also increases in hypertrophy.
• If there is an increase in the workload to a cell or a tissue, hypertrophy occurs.
• Hypertrophy occurs in tissues that cannot increase cell number as an adaptive response.
• It may be a normal physiological response, such as increase in cell mass as seen with exercise.
• It may also be pathologic as in case of cardiac hypertrophy, which is seen with prolonged hypertension.
• It may also be a compensatory process. When one kidney is removed, the other kidney hypertrophies to increase the functional capacity.