Which term refers to an increase in the size and number of cells?

The term that refers to an increase in the size and number of cells is hyperplasia. Hyperplasia is a physiological process where cell division increases, leading to an enlargement of tissue or organ. This is typically a normal response to stimuli, such as hormonal changes, and is often seen, for example, in the endometrium of the uterus during the menstrual cycle or in the prostate gland as men age.

In contrast, hypertrophy refers specifically to an increase in the size of existing cells rather than their number, which is different from hyperplasia. Atrophy indicates a decrease in size or wasting away of an organ or tissue due to a reduction in cell size or number. Metaplasia describes a process where one type of adult cell is replaced by another type, often as an adaptive response to chronic irritation or injury, but it does not involve an increase in cell number or size. Understanding these terms is crucial in health science, as they describe different cellular responses to various stimuli.