Answer
Bone growth in length occurs at the epiphyseal plate and involves the replacement of cartilage tissue with bone tissue, while bone growth in thickness occurs at the periosteum and involves the deposition of new bone tissue on the outer surface of the bone. These two processes work together to ensure proper bone development and maintenance throughout the lifespan of an individual.
Work Step by Step
Bone growth in length (also known as longitudinal growth) and bone growth in thickness (also known as appositional growth) are two distinct processes that occur in bones.
Bone growth in length occurs at the epiphyseal plate, which is a layer of hyaline cartilage located at the ends of long bones in children and adolescents. The process of bone growth in length involves the following steps:
1. Chondrocytes in the epiphyseal plate divide and multiply, leading to the formation of new cartilage tissue.
2. The cartilage cells undergo hypertrophy and calcification, making the matrix of the cartilage harder.
3. Osteoblasts invade the calcified cartilage and deposit new bone tissue, which replaces the cartilage matrix.
4. The new bone tissue formed at the epiphyseal plate adds to the length of the bone.
Bone growth in thickness, on the other hand, occurs at the periosteum, which is a dense layer of connective tissue that covers the outer surface of bones. The process of bone growth in thickness involves the following steps:
1. Osteoblasts in the periosteum deposit new bone tissue on the outer surface of the bone, adding to its thickness.
2. As the new bone tissue is deposited, the diameter of the bone increases.
3. Osteoclasts break down old bone tissue in the inner surface of the bone, maintaining its shape and size.
4. This process of bone deposition and resorption at the periosteum continues throughout the life of the bone, contributing to its strength and resilience.
