Question

question 44
what is the site of longitudinal growth in long bones?
a epiphyseal plate
b sharpeys fibers
c endosteum
d epiphysis
e medullary cavity

Explanation:

• Epiphyseal plate: It is a hyaline cartilage plate in the metaphysis at each end of a long bone. It is the site of longitudinal growth as chondrocytes in the epiphyseal plate divide and secrete extracellular matrix, and then ossification occurs to add length to the bone.
• Sharpey's fibers: These are collagenous fibers that connect periosteum to bone (or cementum in teeth). Their function is to anchor the periosteum (or periodontal ligament in teeth) to the bone, not related to longitudinal bone growth.
• Endosteum: It is a thin vascular membrane of connective tissue that lines the inner surface of the bony tissue that forms the medullary cavity of long bones. It is involved in bone remodeling (resorption and formation) but not the main site of longitudinal growth.
• Epiphysis: It is the end part of a long bone, initially growing separately from the diaphysis. While it is part of the bone - joint complex, the growth in length occurs at the epiphyseal plate (which is between the epiphysis and diaphysis), not the epiphysis itself (except for some appositional growth on its surface which is minor compared to longitudinal growth at the plate).
• Medullary cavity: It is the central cavity of bone shafts where red bone marrow and/or yellow bone marrow (adipose tissue) is stored. It has no role in longitudinal bone growth.

Answer:

A. epiphyseal plate