The structure that replaces the epiphyseal plate in adult bone is the _
A epiphyseal line
B yellow bone marrow
C periosteum
D medullary cavity
The correct answer and explanation is:
The correct answer is A) epiphyseal line.
The epiphyseal plate, also known as the growth plate, is a layer of cartilage found in the long bones of children and adolescents. This plate is the site of bone elongation during growth. As a person matures, the epiphyseal plate gradually ossifies and is replaced by bone, leaving behind a thin, hard line known as the epiphyseal line. The epiphyseal line marks the point where the epiphyseal plate used to be, indicating that bone growth has ceased.
In growing individuals, the epiphyseal plate allows for the bones to lengthen by adding new cartilage cells, which are later replaced by bone tissue. However, in adults, once the individual has reached full maturity, this growth process ends. As a result, the cartilage of the plate is replaced by bone through a process called endochondral ossification, resulting in the formation of the epiphyseal line. This line is a remnant of the epiphyseal plate and serves as an indicator that bone growth is complete.
The other options listed are not correct:
- B) yellow bone marrow is primarily involved in storing fat and is located in the medullary cavity of long bones, but it does not replace the epiphyseal plate.
- C) periosteum is the outer membrane covering bones, but it is not involved in replacing the epiphyseal plate.
- D) medullary cavity is the central cavity of long bones where bone marrow is stored, but it does not replace the epiphyseal plate either.
Thus, the correct answer is the epiphyseal line, which is the adult structure that replaces the epiphyseal plate once bone growth has stopped.