What term is used to describe an increase in the number of cells in an organ or tissue?

The term that describes an increase in the number of cells in an organ or tissue is hyperplasia. This physiological process occurs when there is a demand for more functional cells, often in response to increased workload, hormonal stimulation, or other biological signals. Hyperplasia can be a normal adaptive response, such as in the uterine lining during the menstrual cycle, or it can be pathological, as seen in conditions like certain types of tumors.

Hypertrophy, on the other hand, involves an increase in the size of existing cells rather than an increase in cell number. Atrophy refers to a decrease in the size or number of cells, resulting in a reduction of tissue mass. Hypoplasia is a condition where there is incomplete development or underdevelopment of a tissue or organ, leading to fewer cells than normal. Understanding these terms is essential for differentiating between various cellular adaptations and pathological states in clinical practice.