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Chp 9
Skeletal Muscular System
Question | Answer |
---|---|
3 types of muscle tissue | Skeletal, Cardiac, and Smooth |
Excitability | Response to stimulus |
Contractability | Shorten & exert tension |
Extensibility | Can contract even when stretched |
Elasticity | Rebound to original length after contraction |
Produces movement of skeleton | Skeletal Muscle |
Maintains posture and body position | Skeletal Muscle |
Supports soft tissue | Skeletal Muscle |
Guards orifices | Skeletal Muscle |
Maintains body temp. | Skeletal Muscle |
Epimysium | Surrounds WHOLE muscle |
Perimysium | Connective tissue layer that surrounds COLLECTION of Muscle Fibers |
Fasiculus | Connective tissue layer that has little compartments with compartments in it |
Endomysium | Connective tissue layer that surrounds INDIVIDUAL muscle fibers |
Tendons | connect muscle to bone; interwoven into periosteum and matrix of bone- forming a strong bond |
Collagen bundles of these converge to form tendonds | Epimysium, perimysium, and endomysium |
Aponeurosis | Thickened, Flattened TENDON |
Skeletal Muscle Fiber | = Muscle Cell |
Muscle Fiber/Cell | Large, cylindrical, multinucleated, long, striated, voluntary |
Sacrolemma | Cell membrane |
Transverse tubules (T-tubules) | invaginations of sacrolemma which carry electrical impulses |
Sacroplasm | Cytoplasm of muscle cell. |
Myofibrils | In sacroplasm, made up of myofilament/protein, (actin=thin, myosin= thick) Responsible for Contraction & Shortening. |
Sacroplasmic Reticulum | Surrounds myofibrils in the sacroplasm of a muscle cell. |
Sacromere | Smallest unit of muscle fiber in the sacroplasmic reticulum. |
Attatched to the sacrolemma at each end of the cell | Myofibril (as long as the muscle cell) |
A band | Thick filaments |
I band | Thin filaments |
Sliding Filament Theory | *Requires Calcium and ATP* Explains how muscle fiber exerts tension. Active sites on actin filaments. Head of myosin filament. Crossbridge of head of myosin to active site of actin. Attachment, pivot, detach (Ca gone), return |
Neuromuscular Joint | Where each skeletal muscle fiber is stimulated by a nerve fiber. Chemical Communication |