Chapter 32, Problem 21A

Summary Introduction

Introduction:

Bone and cartilages are types of connective tissue. The skeleton system of the human body is made up of bones of different shapes and sizes. Long bones are present in arms and legs. Wrist bones are short bones. Skull is made up of flat bones. Vertebrae and facial bones are irregular bones.

Answer to Problem 21A

Correct answer:

The correct answer is option (c) osteoclasts.

Explanation of Solution

Explanation/justification for the correct answer:

Option (c) osteoclasts. Replacing old bone cells with a new one is known as remodeling of bone. Osteoclasts help in this process by breaking down old bone cells and replacing it with new bone tissues.

Explanation for incorrect answer:

Option (a) osteoblasts. Osteoblasts are the living bone-forming cells. They help in the formation of new bones. Osteoblasts have one nucleus and work in a group for the formation of bone.

Option (b) osteocytes. Osteocytes are the type of osteoblasts which is trapped in the bone matrix. They keep bone healthy. These cells create a connection between bone and their surrounding through a tiny channel known as canaliculi.

Option (d) osteozymes. Osteozymes is not a cell it is a drug for pain relief. Thus, it cannot be the correct answer.

Conclusion

Osteoclasts break down the old cells of the bone and replace it with new bone tissue thus, option (c) osteoclasts is a correct answer.