Skeletal Muscle Injury Repair PDF Study Guide

Study Guide Skeletal Muscle Injury Repair A. Describe the process of repair following a muscle strain or contusion 1. Hemostasis and hematoma formation 2. Degeneration i. Necrosis (a) Ne...

Study Guide Skeletal Muscle Injury Repair A. Describe the process of repair following a muscle strain or contusion 1. Hemostasis and hematoma formation 2. Degeneration i. Necrosis (a) Neutrophils are the first on the scene ii. Chemotactic agents released to attract inflammatory mediators 3. Inflammation i. Begins within 24-48 hours following injury ii. Phagocytosis of cellular debris iii. Macrophages cause stimulation of satellite cells (a) Migrate to the region (b) Differentiate (c) Various cytokines released (see Point C) iv. T-lymphocytes dominate after macrophages wane (a) Various cytokines released (see Point C) 4. Regeneration i. 6-8 weeks after injury ii. Remodeling occurs after regeneration 5. Fibrosis may occur (but not necessarily) i. Less functional B. Describe the role of the basement membrane in muscle healing 1. Basement membrane must remain intact for regeneration to occur i. Division of satellite cells maintain this (a) Combine with other myogenic cells (b) Fuse with remaining muscle fibers ii. If basement membrane is not intact, fibrosis results (a) Maintains structural integrity of muscle (b) Lacks functional capacity (c) Increased risk of re-injury C. State the five effects that cytokines can have on satellite cells / muscle cells during repair 1. Enhanced resistance to oxidative stress i. Cell survival 2. Block myofibrogenesis i. Improved muscle healing 3. Proliferation i. Cell division 4. Differentiation i. Fusion to myofibers 5. Angiogenesis i. Vascular supply to new muscle cells