Question

multiple choice 2 points
when ______ become enclosed in lacunae, they become ______.
osteocytes; osteoclasts
osteogenic cells; osteoblasts
osteocytes; osteoblasts
osteoblasts; osteocytes
osteoblasts; osteoclasts

Explanation:

Analyze the question stem

The question asks: "When ______ become enclosed in lacunae, they become ______." This refers to the process of bone formation (ossification) and the transition of bone cells.

Identify bone cell roles

Using our knowledge of Bone Histology, we analyze the roles of different bone cells:

• Osteogenic cells are stem cells that differentiate into osteoblasts.
• Osteoblasts are bone-forming cells that secrete the organic bone matrix (osteoid).
• Osteocytes are mature bone cells residing in tiny spaces called lacunae.
• Osteoclasts are large, multinucleated cells responsible for bone resorption (breakdown).

Determine the cellular transition

During bone deposition, active osteoblasts secrete osteoid around themselves. As this matrix calcifies, the osteoblasts become trapped or enclosed within small spaces called lacunae. Once fully enclosed in these lacunae, their metabolic activity changes, and they differentiate into mature, monitoring bone cells known as osteocytes.

Evaluate the given options

• "osteocytes; osteoclasts": Incorrect. Osteocytes do not turn into osteoclasts.
• "osteogenic cells; osteoblasts": Incorrect. Osteogenic cells differentiate into osteoblasts before matrix entrapment.
• "osteocytes; osteoblasts": Incorrect. This is the reverse of the actual developmental process.
• "osteoblasts; osteocytes": Correct. When osteoblasts become enclosed in lacunae, they become osteocytes.
• "osteoblasts; osteoclasts": Incorrect. Osteoblasts do not differentiate into bone-resorbing osteoclasts.

Answer:

• osteocytes; osteoclasts
• osteogenic cells; osteoblasts
• osteocytes; osteoblasts
• osteoblasts; osteocytes (Correct answer)
• osteoblasts; osteoclasts