1. Topic 006 Muscle Tissue Objectives: At the end of this practical you should be able to : 1. Specify and interpret light microscope sections of stained muscle. (eg. Muscle type, structure, fibre type, metabolic profile). 2. Identify structural features, similarities and differences between various types of muscle fibres. SLIDE 101 Limb - mouse. Examine this section under low power. Distinguish between the muscle groups and the limb bone in the centre of the section. Make a labelled drawing to show the bundles of muscle fibres, epimysium, perimysium and endomysium. SLIDES 101/102 Limb - mouse Use either slide. Under high power make two drawings of muscle fibres seen in : a) Transverse section. b) Longitudinal section. Ensure that you include key features which allow you to characterise skeletal muscle, such as multinucleated cells with peripherally located nuclei. Also note the endothelial cell nuclei of capillaries between the fibres. 1 Striated Skeletal Muscle TS (transverse section) LS (longitudinal section)

2. Q 1. What is the major protein product found in the A – band? ……………………. Q 2. What is the major protein product found in the Z – line? ……………………. Q 3. What is the major protein product found in the I – band? ……………………. SLIDE 103 Striated skeletal muscle - rat This slide has been stained with Heidenhain’s Haematoxylin. Select a suitable area, then observe under high power. Draw a group of muscle fibres seen in longitudinal section. Illustrate myofibrils, cross-striations, muscle fibre nuclei and endomysium. Identify: A – bands, I – bands and Z – lines. SLIDE 104 Striated skeletal muscle, Myotendon junction (diaphragm) - dog Make a drawing under low power to illustrate the tapering muscle and the continuity of its connective tissue sheaths and the tendon. Q 4. What is the major protein product found in the tendon matrix? …………………… Q 5. What cells produce this matrix? ……………………………………………………… SLIDE 105 Striated skeletal muscle, (diaphragm) - dog Examine the striated skeletal muscle and the adjacent tendon. This section is stained blue-black with Heidenhains’ haematoxylin, this emphasises the cross-striations of the muscle and the wavy bundles of collagen fibres within the tendon.

3. Examples of Striated skeletal muscle SLIDE 1 Lip of cat Identify striated muscle fibres in this section. Q 6. What feature(s) is/are most helpful in aiding your identification? SLIDE 3 Tongue of cat Identify striated muscle fibres in this section. Q 7. How would you describe the orientation of the various fibre bundles? SLIDE 28 Oesophagus of dog Identify striated muscle fibres in this section. Q 8. Does this muscle layer extend throughout the organ in the dog? Q 9. How about in the cat? 2 Striated Cardiac Muscle SLIDES 106 Striated Cardiac Muscle - cat Choose a suitable field to illustrate some muscle fibres seen in longitudinal section. Identify key features of cardiac muscle such as intercalated discs, central nuclei, peri-nuclear cytoplasm free of striations and branching fibres. Locate muscle fibres cut transversely to illustrate their nuclei and cut ends of myofibrils. Q 10. Cardiac muscle fibres are unicellular – True or False?

4. 3 Smooth Muscle Slide 42 duodenum of mouse and Slide 45 duodenum of cat. 42 – transverse section through wall of duodenum. 45 – longitudinal section through wall of duodenum. Use slide 45. make a low power drawing of smooth muscle cells seen in transverse and longitudinal section. Use slide 42. illustrate smooth muscle cels in transverse and longitudinal section under high power. Q 11. With respect to the organ can you define the two muscle layers? Q 12. What is the functional significance of the arrangement of the muscle cells in these structures? Q 13. Smooth muscle fibres are unicellular – True or False? Examples of smooth muscle SLIDE 57 arteries - dog Identify smooth muscle cell nuclei in the walls of these arteries. Q 14. What is the functional significance of the arrangement of muscle cells in these structures? SLIDE 92 ureter Identify smooth muscle cell nuclei in the wall of this organ. Q 15. What is the functional significance of the arrangement of muscle cells in this structure? SLIDE 180 uterus - cat Identify smooth muscle cell nuclei in the wall of this organ. Q 16. What is the functional significance of the arrangement of muscle cells in this structure?