How does skeletal muscle heal when mature muscle cells cannot proliferate?

How does skeletal muscle heal when mature muscle cells cannot proliferate?

• A. Fibroblasts differentiate to form new muscle fibers
• B. Myoblasts migrate from surrounding tissue to fill defect
• C. Satellite cells proliferate and differentiate to form new skeletal muscle cells following death of muscle fibers
• D. Stem cells from bone marrow contribute to regeneration

Answer: (C)

Adult skeletal muscle repairs itself mainly through resident muscle stem cells called satellite cells. These cells sit quietly between the muscle fiber membrane and its surrounding basement membrane and are activated when injury occurs. Once activated, they proliferate to form new myoblasts, which then differentiate and fuse to repair or replace damaged fibers, or to form new fibers if needed. This is how mature muscle can regenerate even though the mature muscle cells themselves don’t divide. Fibroblasts can contribute to scar tissue formation rather than creating new muscle fibers, so relying on them alone does not explain true muscle regeneration. Myoblasts migrating from surrounding tissue isn’t the primary mechanism; the targeted, local response comes from satellite cells. Stem cells from bone marrow may participate in some contexts, but they are not the main source of regenerating skeletal muscle in adults.

Adult skeletal muscle repairs itself mainly through resident muscle stem cells called satellite cells. These cells sit quietly between the muscle fiber membrane and its surrounding basement membrane and are activated when injury occurs. Once activated, they proliferate to form new myoblasts, which then differentiate and fuse to repair or replace damaged fibers, or to form new fibers if needed. This is how mature muscle can regenerate even though the mature muscle cells themselves don’t divide.

Fibroblasts can contribute to scar tissue formation rather than creating new muscle fibers, so relying on them alone does not explain true muscle regeneration. Myoblasts migrating from surrounding tissue isn’t the primary mechanism; the targeted, local response comes from satellite cells. Stem cells from bone marrow may participate in some contexts, but they are not the main source of regenerating skeletal muscle in adults.