L-02 Histology of muscle.xml

L-02 Histology of muscle.xml - Lecture 2 Histology of...

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Lecture 2. Histology of Muscle Lecture 2. Histology of Muscle Lecture 2. Histology of Muscle H. Warshawsky Dr Morales References Gartner and Hiatt, Chapter 8, pp.131-154; Alberts et al., 1995, Chapter 16, including pp. 847-855. Objectives Students should be capable of answering the following: 1. Describe the morphological and molecular basis of the cross-striations on skeletal muscle fibres. 2. Describe the appearance of cross-sectioned skeletal muscle with the electron microscope at each band of the sarcomere unit. 3. Describe the relationship between skeletal muscle fibres and the connective tissue that makes up the organ called “a muscle”. 4. Describe the light microscopic distinction between skeletal and cardiac muscle. 5. Describe the components of the intercalated disc. 6. Compare the sarcoplasmic reticulum in the three muscle types. 7. Describe the structure and basis of contraction of smooth muscle. 8. Describe the three types of muscle in both longitudinal and cross-section. Because muscle cells, or fibres, are elongated they will look very different in longitudinal and cross-section. It is important to know the diagnostic features of each muscle type in all planes of section. Classification of Muscle : 1. Striated muscle or skeletal muscle -striated, voluntary muscle attached by connective tissue to bones. 2. Smooth muscle -no cross striations, involuntary muscle 3. Cardiac muscle -striated involuntary muscle of the heart Skeletal Muscle : This muscle is the most abundant type of muscle in the body. It can be considered as a basic tissue (striated muscle) or an organ. Muscle is associated with connective tissue. Muscle cells, called fibres, are attached to connective tissue collagen by junctional complexes associated with infolding of the unit membrane of the muscle fibre. In addition, there are 3 coats of connective tissue that organize the muscle: Epimysium is the dense connective tissue that surrounds the entire muscle. Perimysium is the connective tissue that surrounds each bundle of fibres or fascicles.
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Lecture 2. Histology of Muscle Lecture 2. Histology of Muscle Endomysium is the thin layer of connective tissue surrounding each muscle fibre and includes the basal lamina and the associated reticular fibrils (collage type III) and elastic fibres. The capillaries that supply blood to the muscle fibres are in this tissue. Muscle Cell or Fibre : The cells of muscle are elongated and run between 1-40 mm in length. They are called muscle fibres, not to be confused with connective tissue fibres, such as collagen and elastin. The diameters of the muscle fibres range between 10-100 μm. Each fibre is multinucleated and results from the embryonic fusion of uninucleated myoblasts. The cell membrane, or unit membrane, is the sarcolemma and the cytoplasm is called sarcoplasm. Each muscle fibre is surrounded by a basal lamina with the associated reticular fibres that make up the endomysium. The multiple nuclei are situated peripherally just under the sarcolemma. Satellite cells are stem cells that sit
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This note was uploaded on 01/16/2012 for the course BI 200 taught by Professor Potter during the Fall '11 term at Montgomery College.

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L-02 Histology of muscle.xml - Lecture 2 Histology of...

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