Term
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Definition
- striated
- voluntary
- somatic innervation
- many nuclei per cell
- Ca2+ required for contraction
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Term
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Definition
- striated
- involuntary
- autonomic innervation
- 1-2 nuclei per cell
- Ca2+ required for contraction
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Term
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Definition
- nonstriated
- involuntary
- autonomic innervation
- 1 nucleus per cell
- Ca2+ required for contraction
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Term
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Definition
- basic contractile unit of striated muscle
- made of thick (myosin) and thin (actin) filaments
- troponin and tropomyosin are found on the thin filament and regulate actin-myosin interactions
- titin anchors actin and myosin filaments together, preventing excessive stretching of the muscle
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Term
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Definition
| marks the boundary of the sarcomere |
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Term
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Definition
| located in the middle of the sarcomere |
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Term
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Definition
| contains only thin filaments |
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Term
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Definition
| consists of only thick filaments |
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Term
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Definition
| contains the thick filaments in their entirety; the only part of the sarcomere that maintains a constant size during contraction |
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Term
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Definition
| many sarcomeres attached end to end; many myofibrils make up a myocyte |
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Term
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Definition
| surrounds myofibrils; a modified ER that contains calcium |
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Term
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Definition
| the cell membrane of a myocyte |
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Term
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Definition
| a system of tubes connected to the sarcolemma and oriented perpendicularly to teh myofibrils allowing the incoming signal to reach all parts of the muscle |
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Term
| What are the steps in muscle contraction? |
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Definition
- Begins at the neuromuscular junction, where the motor neuron releases acetylcholine that binds to receptors on the sarcolemma causing depolarization
- This depolarizaiton spreads down the sarcolemma to the T-tubules, triggering the release of calcium ions
- Calcium binds to troponin, causing a shift in tropomyosin and exposure of the myosin-binding sites on the actin thin filament
- Shortening of the sarcomere occurs as mysoin heads bind to the exposed sites on actin, forming cross bridges and pulling the actin filament along the thick filament, resulting in contraction. This is known as the sliding filament model
- The muscle relaxes when acetylcholine is degraded by acetylcholinesterase, terminating the signal and allowing calcium to be brought back into the SR, ATP binds to the myosin head, allowing it to release from actin
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Term
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Definition
| the response of a single muscle fiber to a brief stimulus at or above threshold; all-or-nothing response |
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Term
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Definition
| the addition of multiple simple twitches before the muscle has an opportunity to fully relax |
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Term
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Definition
| simples twitches that occur so frequently as to not let the muscle relax at all to produce a more prolonged and stronger contraction |
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Term
| What are two forms of energy reserves found in muscles? |
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Definition
- creatine phosphate can transfer a phosphate group to ADP, forming ATP
- myoglobin is a heme-containing protein that is a muscular oxygen reserve
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Term
| What does the axial skeleton consist of? |
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Definition
| skull, vertebral column, ribcage, and hyoid bone |
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Term
| What does the appendicular skeleton consist of? |
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Definition
| bones of the limbs, the pectoral girdle (shoulder) and the pelvis |
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Term
| What embryonic layer is bone derived from? |
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Definition
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Term
| compact bone vs. spongy/cancellous bone |
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Definition
- provides strength and is dense
- has a lattice-like structure consisting of large spicules known as trabeculae, cavities are filled with bone marrow
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Term
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Definition
| contain shafts called diaphyses that flare to form metaphyses adn that terminate in epiphyses. The epiphysis contains an epiphyseal (growth) plate that causes linear growth of the bone |
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Term
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Definition
| layers of connective tissue surrounding the bone that gives tendons and ligaments something to attach to; also important for repairing and maintaining bone |
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Term
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Definition
| concentric rings called lamellae aruond a central Haversian or Volkmann's canal; this structural unit is called an osteon or Haversion system and many of these make up bone |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| firm, elastic material secreted by chondrocytes; matrix is called chondrin |
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Term
| endochondral ossification |
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Definition
| bones that form from cartilage |
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Term
| intramembranous ossification |
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Definition
| bones that form directly from undifferentiated tissue (mesenchyme) in intramembranous ossification |
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Term
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Definition
| encloses the actual joint cavity |
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