Which term denotes an increase in the size of an organ or tissue due to the increase in the number of cells?

The term that denotes an increase in the size of an organ or tissue due to the increase in the number of cells is hyperplasia. Hyperplasia is a physiological process where cell proliferation leads to an increase in the overall mass of the tissue. This can occur in response to various stimuli, such as hormonal changes or increased demand for function, and is often seen in tissues that have a high capacity for regeneration.

For instance, the endometrium (the lining of the uterus) undergoes hyperplasia in response to hormonal changes during the menstrual cycle, allowing it to prepare for potential implantation of an embryo. In this way, hyperplasia plays an important role in both normal physiological processes and certain pathological conditions.

Other terms like hypertrophy relate more specifically to an increase in the size of cells rather than their number. Understanding the distinction between these terms can help clarify the underlying mechanisms at play in various medical conditions.