Term
| what are two ways skeletal muscle fibers are attached to the periosteum of the bones |
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Definition
1) directly
2) tendon (strong, fiberous cord) |
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Term
| what muscle attachment stays stationary during contraction |
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Definition
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Term
| what moves attached to the bone contracts when the muscle does? |
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Definition
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Term
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Definition
| muscle group causing an action |
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Term
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Definition
| muscle group that counters movement |
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Term
| the force of contraction remains relatively constant as the muscles shorten in length |
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Definition
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Term
| the length of the muscles does not change as force is exerted |
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Definition
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Term
| how many muscle fibers are contained in a skeletal muscle |
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Definition
| each muscle fiber encloses a bundle of 4-20 myofibrils (elongated structures) |
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Term
| what are each myofibril composed of? |
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Definition
| thick and thin myofilaments |
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Term
stacked thick and thin myofilaments
dark bands |
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Definition
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Term
| center of the A band, consisting of thick bands only |
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Definition
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Term
consist of only thin myofilaments
light bands |
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Definition
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Term
| divided into two halves by a disc of protein |
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Definition
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Term
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Definition
distance between two Z lines
smallest subunit of muscle contraction |
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Term
| why do muscles contrast and shorten? |
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Definition
| because myofibrils contract and shorten as well |
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Term
| what does myosin consist of? |
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Definition
| 2 polypeptide chains wrapped around each other, ending with a globular head |
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Term
| what is a thin filament composed of? |
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Definition
| 2 chains of actin protein twisted together in a helix |
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Term
| what is composed of several myosin subunits packed together |
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Definition
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Term
| muscle contraction involves a series of events called... |
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Definition
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Term
| what activates the head for the later power stroke |
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Definition
| hydrolysis of ATP by myosin |
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Term
| what binds to actin forming a cross bridge? |
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Definition
| ADP and Pi remains bounded to the head |
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Term
| what happens during the power stroke |
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Definition
| Myosin takes original shape, releasing ADP and Pi |
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Term
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Definition
| ATP binds to the head, releasing actin |
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Term
| when a muscle is related, it's myosin head cannot be binded to actin because the attachment sites are blocked by ... |
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Definition
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Term
| what removes tropomyosin so that the muscle can contract? |
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Definition
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Term
| what does this process do? |
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Definition
| it is regulated by the Ca2+ levels in the muscle fiber cytoplasm |
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Term
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Definition
| tropomyosin inhibits cross bridge formation |
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Term
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Definition
the Ca2+binds to troponin
tropomyosin is displaced, allowing the formation of actin-myosin cross bridges |
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Term
| when a muscle fiber is stimulated to contract by motor neurons .. what is secreted? |
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Definition
| acetylcholine at the neuromuscular junction, making the membrane depolarized |
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Term
| depolarization is conducted down the.. |
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Definition
| transverse tubules (T tubules) |
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Term
| the sarcosplasmic reticulum releases what when stimulated? |
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Definition
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Term
| what does a motor unit consist of |
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Definition
| it consists of a motor neuron and all the muscle fibers it innervates |
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Term
| what happens to the fibers when a motor neuron produces impulses? |
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Definition
| all fiber contracts together |
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Term
| when do muscles need small/large motor units? |
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Definition
small: when the muscle requires precise control
large: requires less precise control but needs more force |
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Term
| what is called when the cumulative increase in motor unit number and size leading to a stronger contraction? |
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Definition
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Term
| what is it called when a muscle stimulated with a single quick electric shock and than is relaxed quickly? |
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Definition
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Term
| what is it called when there is a second twitch .. kind of like a piggy back twitch? |
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Definition
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Term
| what is it called when there is 2 twitches back to back |
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Definition
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Term
| what contraction speed is rich in capillaries, mitochondria, and myoglobin (red fibers)? |
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Definition
| slow-twitch or type 1 fibers |
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Term
| with a slow twitch, how long can they sustain an action? |
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Definition
| can sustain action for a long period of time |
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Term
| what type of contraction speed is poor in capilliaries, mitochondria and myoglobin (WHITE fibers)? |
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Definition
fast twitch or type ll, fibers
adapted for rapid power and generation |
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Term
| where do skeletal muscles gain most of their energy from at REST? |
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Definition
| get energy from aerobic respiration of fatty acids |
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Term
| where do skeletal muscles get their energy from when they are IN motion? |
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Definition
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Term
| the max rate of O2 consumption in the body is called .. |
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Definition
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Term
| locomotion in large animals is called? |
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Definition
| appendicular locomotion & axial locomotion |
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Term
| what is appendicular locomotion produced by? |
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Definition
| appendages that oscillate |
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Term
| what is the axial locomotion produced by? |
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Definition
| produced by bodies that undulate, pulse or undergo peristalitic waves |
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Term
| what are some physical constrains to movement? |
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Definition
| gravity and frictional drag |
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Term
| what does swimming involve? |
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Definition
involves using the body or its appendages to push against the water
ie. eel uses whole body
trout uses only its postirior |
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Term
| how do terrestrial tetrapod vertebrates able to swim? |
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Definition
through limb movement
typically have webbed feet/flippers |
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Term
| Vertebrates are tetrapods; all arthropods have atleast ___ limbs |
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Definition
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