What cells are primarily responsible for muscle repair and growth after injury?

• A. Satellite cells
• B. Myoblasts
• C. Fibroblasts
• D. Neurons

Answer: (A)

Satellite cells are the muscle’s own stem cells that drive repair and growth. They sit between the muscle fiber membrane and its surrounding basal lamina and stay relatively quiescent until injury signals activate them. Once activated, they multiply and become myoblasts, which then fuse with damaged fibers or fuse together to form new muscle fibers. This fusion donates nuclei to the fibers, boosting the muscle’s capacity to synthesize proteins and rebuild after injury, which underlies both recovery and growth from training.

Myoblasts are the immediate progenitors that arise from satellite cells during this process, fibroblasts produce connective tissue rather than muscle fibers, and neurons are nerve cells not directly involved in repairing or growing muscle tissue.