In endochondral ossification, which type of tissue is initially replaced by bone?

• A. Fibrous connective tissue
• B. Adipose tissue
• C. Elastic cartilage
• D. Hyaline cartilage

Answer: (D)

Verified step by step guidance

1. Understand the process of endochondral ossification: This is a developmental process where bone tissue replaces an existing cartilage model. It is essential for the formation of long bones and other skeletal structures during growth.
2. Identify the type of cartilage involved: In endochondral ossification, the cartilage that serves as the initial model is hyaline cartilage. Hyaline cartilage is a smooth, glass-like tissue that provides a template for bone formation.
3. Differentiate hyaline cartilage from other tissue types: Fibrous connective tissue, adipose tissue, and elastic cartilage are not involved in this process. Hyaline cartilage is specifically suited for this role due to its structural properties and ability to be replaced by bone.
4. Recognize the stages of replacement: Hyaline cartilage is gradually broken down and replaced by bone tissue through a series of steps, including chondrocyte hypertrophy, matrix calcification, and invasion by osteoblasts and blood vessels.
5. Apply this knowledge to the question: The correct answer is hyaline cartilage because it is the specific tissue type that is replaced during endochondral ossification, unlike fibrous connective tissue, adipose tissue, or elastic cartilage.