Exercise 10

1. Exercise 10 Muscle histology

2. Muscle Types • Skeletal – attached to bone by tendons is responsible for voluntary movements. • Cardiac- located in heart • Smooth- located in the walls of internal organs, blood vessels, and airways

3. Skeletal muscle fibers • Connective tissue layers: • Epimysium- around the entire muscle • Perimysium surrounds bundle of muscle fibers (fascicle) • Endomysium-surrounds each muscle fiber

4. Skeletal muscle cont. • Striations in appear because of alternating light and dark bands from the arrangement of the thick and thin protein filaments called myofibrils.

5. Skeletal muscle

6. Cardiac muscle • Forms branching networks. • Striated • Linked together by intercalated discs

7. Smooth Muscle • Widest in middle and tapered toward each end. • Single nucleus

8. Cell structure of skeletal muscle • Actin- main component of thin filaments. • Myosin- main component of thick filaments • Together these are called myofilamentswhich are packaged into parallel bundles called myofibrils.

9. Structure of a skeletal muscle fiber

10. Structure of a skeletal muscle fiber • Sarcolemma or cell membrane • T-tubules-continuous with the sarcolemma and travel into the cytoplasm • Sarcoplasmicreticulum-SER • Cisternae- saclike extensions of the SR

11. Neuromuscular Junctions • Synaptic terminal- the expanded knob at the end of the nerve fiber • Motor end plate-the region of the sarcolemma associated with the neuromuscular junctions. • Synaptic cleft- narrow space between the cell membrane

12. The End • View the different types of muscle under the microscope. • Be able to ID the various terms on models, pictures or on slides