Muscle Tissue Pt 3 Flashcards
What are the different phases of tissue repair?
Destruction/Degeneration
Inflammation
Regeneration
Remodeling/Fibrosis
What occurs in the destruction/degeneration phase of muscle repair?
- Initial rupture and necrosis of myofibers
- Influx of Macrophages
- Pro-inflammatory
What occurs in the Inflammatory phase of muscle repair?
-Local macrophages begin tissue clean up
What occurs in the Regeneration phase of muscle repair?
Satellite cells migrate to the area and begin reconstruction phase
- Fibroblast begins producing connective tissue scar
- Capillary ingrowth occurs
What is the function of Neutrophils in tissue repair?
these are WBCs that are the first to arrive on the sight of injury
What is the function of Monocytes in tissue repair?
these are the WBCs that arrive later and perform endocytosis, precursors to macrophages
What is the function of Macrophages in tissue repair?
M1 cleans the sight of injury, M2 release anti-inflammatory molecules and growth factors
What is meant by the phrase “Coordinated vascular and cellular response of the body to cell injury and cell death” as it relates to inflammation?
this is the definition of inflammation and the process of what occurs in this phase of injury
Erythema
redness- vasodilation and increase blood flow
Heat
if the area is warm- vasodilation and increased blood flow
Edema
fluid and cells leaking from local blood vessels into the extravascular spaces
Pain
Direct trauma; chemical mediation by bradykinins, histamines, serotonin; internal pressure secondary to edema; swelling of the nerve endings
Loss of function
keeps you from “return to play” ex. sprained ankle
Satellite cells
small mononuclear progenitor cells or stem cells with no cytoplasm
- located in the sarcolemma and the BM of muscle fibers
- quiescent until called upon for injury (chillin until needed)
- function as a reserve population of the embryonic muscle called that can be recruited and stimulated to mature into adult muscle cells
Clinical significance of satellite cells with aging
numbers of satellite cells decline with age so it takes longer for an injury to repair
What is the fate of satellite cells and the path
- after muscle damage occurs, they are activated
- once activated, they become precursor muscle cells (skeletal myoblasts) and then merge with mature cells in the area of injury
Distinguish between a myoblast, myocyte, a myotube and a myofiber.
- Myocytes are tubular muscle cells or fibers that develop from myoblasts. They are specialized as cardiac, skeletal, or smooth muscle cells.
- myoblasts are a type of embryonic stem cell that gives rise to muscle cells.
- Muscle fibers form from the fusion of myoblasts into multi-nucleated fibers called myotubes
- Myofibers are muscle cells specialized to contract