Exercise 10 Muscle histology

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

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

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.

Skeletal muscle

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

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

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

Structure of a skeletal muscle fiber

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

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

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