How is hyperplasia defined in a medical context?

In a medical context, hyperplasia is specifically defined as an increase in cell number due to division. This occurs when there is an increase in the reproduction rate of cells, which can lead to a greater overall number of cells within a tissue or organ, contributing to its growth.

Hyperplasia is different from hypertrophy, which refers to the enlargement of existing cells rather than an increase in cell number. The other options provided describe unique biological processes or growth patterns but do not accurately capture the definition of hyperplasia. For instance, the growth of new neurons is more aligned with neurogenesis, and the formation of new muscle fibers pertains to muscular hypertrophy or regeneration rather than hyperplasia itself. Therefore, the correct understanding of hyperplasia highlights its characteristic increase in the number of cells through division, which can be a normal physiological response or a pathological condition.