What is the name of the long end of a bone where growth occurs?

The long end of a bone where growth occurs is referred to as the epiphyseal region, specifically known as the epiphyseal plate or growth plate in growing bones. This area is located between the diaphysis (the main shaft of the bone) and the epiphysis (the wider end of the bone). The epiphyseal plate is composed of cartilage and is crucial for longitudinal bone growth during childhood and adolescence. As new cartilage cells are produced, they push older cells towards the diaphysis, where they eventually turn into bone through a process called ossification.

The epiphyseal plate is essential for the growth in length of long bones. Once an individual reaches maturity, the epiphyseal plate solidifies and is replaced by bone, marking the end of longitudinal growth.

In contrast, the diaphysis refers to the long central shaft of the bone and is not where growth directly occurs. Epinephrine is a hormone and does not relate to bone structure, while the metaphysis is the region adjacent to the epiphyseal plate but is not where active growth occurs; it primarily serves as a transitional area.