Muscular Tissue - Chapter 6 - PDF

MUSCULAR TISSUE DR/ Ghada Mohamed  Chapter 6: Muscular tissue General characteristics 1-Mesodermal in origin. 2-Structural and functional unit is modified cell (muscle fiber). 3-Cell membrane of muscle fiber is called...

MUSCULAR TISSUE DR/ Ghada Mohamed  Chapter 6: Muscular tissue General characteristics 1-Mesodermal in origin. 2-Structural and functional unit is modified cell (muscle fiber). 3-Cell membrane of muscle fiber is called sarcolemma. 4-Cytoplasm of muscle fiber is called sarcoplasm. 5-Sarcoplasm is acidophilic, containing all organelles (rich in mitochondria, sER and inclusions (fat, glycogen & myoglobin pigment). 6-The smooth endoplasmic reticulum is called sarcoplasmic reticulum. 7-The muscle fiber may have transverse striation (Skeletal & Cardiac muscles) or un-striated (Smooth muscle). Skeletal Muscle Site 1- Skeleton. 2- Face, Eye, Tongue, Pharynx, Upper 2/3 of esophagus 3- Diaphragm. 4- Cremasteric muscle Shape Cylindrical, non-branching EXCEPT in face and tongue Sarcolemma clear (very thick). Sarcoplasm a-Organelles: rich in mitochondria, sarcoplasmic reticulum. b-Inclusions: myoglobin, glycogen and lipid droplets. Nucleus: Multiple, peripheral, oval Origin: from the fusion ‫اتحاد‬of mononucleated myoblasts Regeneration can regenerate from satellite cells Organization of muscle fibers a-Epimysium →The connective tissue surrounding whole muscle b-Perimysium→Thin septa of connective tissue around each bundle of muscle fibers. (act as barrier) c-Endomysium→ A layer of connective tissue around each muscle fiber All skeletal muscle voluntary except pharynx, upper 2/3 of Esophagus, Diaphragm, Cremasteric muscle are involuntary Smooth muscle Site Organs + blood vessels Shape Fusiform arranged in layers Sarcolemma Thin Sarcoplasm Acidophilic except dark patches called dense bodies Nucleus Single+ central+ oval Origin UMCs Regeneration After injury→ mononucleated UMCs and Pericyte → mitosis→ replacement degenerated tissue 1  Skeletal Smooth Site Skeleton Organs Shape Cylindrical Spindle‫رسمه العين‬ Size Largest Smallest Sarcolemma Thick Thin Nucleus Multiple, peripheral & oval Single, central nucleus Striations Present Not present Regeneration Regenerated by satellite cells Regenerate dby UMCs Tubular system Triad Not present 2