Histology_(8)_Muscular_tissues Physiotherapy.pptx

Histology

1. Muscular Tissues Muscular tissue is specialized for contraction It arise from the mesoderm specific nomenclature associated with muscles commonly involves the prefix sarco - or myo - The structural and functional units of muscles are formed of special elongated cells known as muscle fibers or myocytes ( myofibers ) The cell membrane of the muscle cells is known as sarcolemma The cytoplasm of the muscle cells is known as sarcoplasm The endoplasmic reticulum of the muscle cells is known as sarcoplasmic reticulum There are 3 types of muscles: Skeletal muscles Cardiac muscles Smooth muscles

2. Structure of muscle fibers Striated muscle fibers Smooth muscle fibers

3. Sarcomere: the area between 2 Z discs is called sarcomere It is the functional contractile unite of the muscle fiber Each sarcomere includes the whole dark band and the 2 halves of the 2 light bands on both sides They contract and relax as one unit

4. Skeletal(Striated) muscles: attaches to skeleton quick and voluntary Contraction long, cylindrical multinucleated cells (syncytium) with peripherally placed nuclei They do not branched except in the tongue and face. They undergo regeneration to a limited degree .

5. 2. Cardiac muscles: Function: contraction - involuntary; rapid and rhythmic - in the heart (myocardium) Basic morphology in LM: cardiac muscle cell (cardiomyocyte) are long branched cells with cross striation Nuclei (1-2) are situated in the center of the cell. Cardiomyocytes are connected by intercalated discs . They can't divide or regenerate.

6. 3 . Smooth muscles: Function: contraction is involuntary; weak and slow - in the wall of hollow organs (stomach, small intestine) Basic morphology in LM: spindle shaped smooth muscle cell . Cytoplasm has no cross striation. Oval or rod-like nuclei in the center . They actively regenerate.