| Abnormality |
 |
|
| Definition |
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|
| Aplasia |
a developmental failure resulting in the absence of an organ or tissue |
| Hypoplasia |
an incomplete development or underdevelopment of an organ or tissue, which is usually the result of a decrease in the number of cells |
| Atrophy |
a wasting or diminution of size or activity of a part of the body, usually the result of an abnormal decrease in cell size |
| Hypertrophy |
an increase in the size of an organ caused by an increase in the size of the cells rather than the number of cells |
| Hyperplasia |
an increase in the number of cells of a body part |
| Dysplasia |
any abnormal development of tissues or organs |
| Anaplasia |
a change in the structure or orientation of cells characterized by the production of abnormal, undifferentiated cells |