Anatomy Chapter 10
Terms
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- Sarco-
- Muscle
- Sliding filament theory (4 steps)
- 1) Action potential causes depolarization and release of calcium from the SR, 2) Calcium diffuses across and binds to troponin to move tropomyosin to allow binding of myosin head to binding sites, 3) Myosin head pivots to pull thin filament, need ATP instead of ATD for myosin head to let go. 4) Calcium actively taken back into SR and the muscle relaxes
- Functions of skeletal muscle
- Movement, posture/position, supports soft tissues, guards entrances and exits (eyes, mouth, anus), temperature (use ATP for muscle contraction. 40% of energy is usable, 60% is given off as heat)
- Surrounds fascicle
- Perimysium
- 3 Types of muscle
- Smooth, cardiac, and skeletal. All 3 designed to contract
- Z-lines
- Thin filament (thin horizontal lines), Thick filament (darker horizonal lines). From one z-line to another is one sarcomere
- Power Stroke
- Pull thin filament across thick filament
- Sarcomere
- Functional unit of muscle where the contraction takes place
- Sarcomere composition
- Thick filament made of myosin (two subunits twisted around each other with 2 tails and 2 heads.) M-line is where the tails come together
- Cross Bridge
- Created when myosin heads bind to active actin sites
- Wrap around the sarcoplasmic reticulum
- T-Tubules
- Surrounds bundles of myofibril protein fibers
- Sarcoplasmic reticulum
- Thin filament proteins
- Actin (2 twisted chains of globular molecules), tropomyosin (blocks myosin binding sites), troponin (moves tropomyosin)
- Causes contraction in muscle
- Must move away tropomyosin from the binding site to allow binding. Control using calcium
- Cell membrane in muscle cell
- Sarcolemma
- Center of sarcomere
- M-line
- Skeletal muscle tissue
- Striated, mostly voluntary (respiratory is involuntary), multinucleate (more than one nucleus) so lots of DNA to code for protein synthesis, tendon attaches muscle to bone
- 2 primary proteins in muscle
- Actin and Myosin
- Long pores in sarcolemma
- T-Tubules (transverse tubules)
- Group of muscle cells
- Muscle fascicle
- Surrounds entire muscle
- Epimysium
- Surrounds muscle filbers
- Endomysium