Correctly order the following steps of bone growth in length by placing a 1 by the first step, a 2 by the second step, and so on.
Calcified cartilage is replaced with bone in the zone of ossification.
Chondrocytes in the zone of proliferation divide by mitosis.
Chondrocytes enter the zone of calcification and die as their matrix calcifies.
Chondrocytes enlarge and cease dividing.

Verified step by step guidance

1. Understand that the process of bone growth in length occurs at the epiphyseal plate (growth plate) and involves several zones: the zone of proliferation, the zone of hypertrophy, the zone of calcification, and the zone of ossification.
2. Identify the first step: In the zone of proliferation, chondrocytes divide by mitosis to produce new cartilage, which pushes the epiphysis away from the diaphysis, lengthening the bone.
3. Identify the second step: In the zone of hypertrophy, chondrocytes enlarge (hypertrophy) and cease dividing, preparing for the next stage of calcification.
4. Identify the third step: In the zone of calcification, the matrix surrounding the chondrocytes calcifies, and the chondrocytes die due to lack of nutrients.
5. Identify the fourth step: In the zone of ossification, the calcified cartilage is replaced with bone tissue by osteoblasts, completing the process of bone lengthening.

Key Concepts

Zones of Growth in Long Bones

Long bone growth occurs in specific zones within the epiphyseal plate, which include the zone of proliferation, zone of hypertrophy, zone of calcification, and zone of ossification. Each zone has distinct functions, such as chondrocyte division and maturation, which contribute to the overall lengthening of the bone.

Chondrocyte Function

Chondrocytes are specialized cells found in cartilage that play a crucial role in bone growth. They undergo processes such as mitosis in the zone of proliferation, enlargement in the zone of hypertrophy, and eventual death in the zone of calcification, which is essential for the transition from cartilage to bone.

Ossification Process

Ossification is the process by which cartilage is transformed into bone. In the zone of ossification, calcified cartilage is replaced by bone tissue, allowing for the structural integrity and strength of the growing bone. This process is vital for the proper development and maintenance of the skeletal system.