Which of the following best describes hyperplasia?

Hyperplasia refers to an increase in the number of cells in a tissue or organ, which can lead to an increase in its size. This condition is generally a response to a stimulus, such as hormonal changes or increased functional demand. For example, during pregnancy, certain tissues in the body, like the breast tissue, undergo hyperplasia in preparation for lactation.

In contrast, a decrease in tissue mass indicates atrophy, which is the loss of cells rather than an increase. The replacement of tissue with scar tissue pertains to fibrosis, often following injury or inflammation, and does not involve an increase in cell number. Normal cell death is known as apoptosis, which is a regulated process important for maintaining tissue homeostasis, and is not associated with an increase in cell number. Understanding these distinctions helps clarify why hyperplasia specifically involves an increase in cell quantity.