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Skeletal Muscle Org.
Structual organization of Skeletal Muscle
Question | Answer |
---|---|
What is the term for a single muscle cell? | Muscle fiber |
The membrane surrounding the muscle fiber is...? | The sarcolemma |
Specialized cytoplasm in the muscle is ...? | sarcoplasm |
What are the threadlike units called made of actin and myosin? | Myofibrils |
The functional unit of muscular contraction is the _____________? | sarcomere |
These discs border the sarcomere on each end. | Z lines |
These are projections on the myosin that physically link with the actin. | cross-bridges |
What network of channels contains Ca++ to help activate muscle contraction? | sarcoplasmic reticulum |
These channels run perpendicular to the sarcomeres and carry the Ca++ that are released by the SR | transverse tubules |
What thin connective membrane surrounds the sarcolemma? | endomysium |
This connective tissue surrounds the whole muscle and is continuous with the tendon. | epimysium |
This connective tissue bundles muscle fibers into fascicles. | perimysium |
This zone disappears when actin is moved towards the center of the sarcomere during a contraction. | H zone |
This area of the sarcomere contains thick, rough myosin filaments, overlapped by thin, smooth actin filaments. | A band/Anisotropic band |
This area of the sarcomere contains contains only thin actin filaments | I band/Isotropic band |
This bisects the sarcomere into two equal portions | M line |