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Apologia Anatomy and Physiology mod 5 the muscul ...

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  • calcium ions are being actively transported into the sarcoplasmic reticulum. Is it the beginning or the ending of a contraction?
    ending, it is resetting the calcium. (Active transport requires energy)
  • What is a threshold stimulus?
    : a stimulus that is strong enough to create one action potential in a neuron.
  • What is the first step of the sliding filament model?
    An action potential causes the sarcoplasmic reticulum to release Calcium into the cell
  • Explain the difference between subthreshold, threshold, submaximal and maximal stimulus.
    Stimuli
  • How does the muscle action potential get to the sarcoplasmic reticulum?
    It travels down the t-tublues
  • Who are the bodyguards of the actin myofilament, and what gets them out of the way? (What buys them off)
    tropomyosin and tropomin, calcium and ATP
  • Two muscle fibers that are right next to each other do not contract at the same time. are they part of the same motor unit?
    no
  • What kind of energy source do muscles take advantage of that requires oxygen and what kinds do not?
    aerobic respiration is very efficient and requires oxygen, using creatine phosphate does not use oxygen, and anaerobic respiration does not require oxygen.
  • The sarcoplasmic reticulum uses active transport to put calcium back onto the organelles. Is this the beginning or end of the contraction?
    End
  • Each muscle has its own nerve to make it move and blood vessel because it is a voracious
    Energy Hog. needing ATP for myosin to bind to the actin and to put the Ca back into the sarcoplasmic reticulum
  • What does acetylcholinesterase do for the muscle?
    Breaks down the neurotransmitter acetylcholine, preventing action potentials from reaching muscle. allowing the muscle to relax
  • What is the byproduct of anaerobic respiration? Why is this a problem?
    Lactic acid, it is a problem when it accumulates in the muscles because it is deleterious to muscle tissue.
  • What is a motor unit?
    motor unit: One motor neuron and all the muscle fibers it innervates.
  • Why do muscles need energy to relax?
    ATP is needed to actively pump calcium ions back into the sarcoplasmic reticulum
  • Explain step E
    Return stroke:ATP breaks down to ADP and P which stays bound to myosin heads.Energy released, myosin heads powered up like a set mouse trap
  • Where is the first place muscles find energy when aerobic respiration can't keep up with demand?
    Creatine phosphate, Creatine phosphate+ADP=creatine phosphate+ATP Only enough energy for 10-15 seconds of contraction
  • What are the z disks?
    a border formed by alternating filaments in a zig zag pattern. it is the anchoring site for the actin myofilaments
  • What is the all or nothing law of muscle contraction?
    a principle that states that the strength of a response of a nerve cell or muscle fiber is not dependent upon the strength of the stimulus.
  • What causes an oxygen debt?
    This occurs when muscles are don't receive enough O2 for anerobic respiration to supply the energy needs. it relies on creatine phosphate and anerobic respirati
  • What happens between the power stroke and the return stroke?
    ATP binds to the myosin heads causing them to release the active sights on the actin. (setting the stage for a sequel)
  • What causes the sliding part of the sliding filament model?
    When the myosin head binds to the actin site and pulls, causing the actin and myosin monofilaments to slide with respect to each other.
  • What shortens in the sarcomere and what stays the same length?
    a-actin, b-myosin, and d- A band stay the same c-h zone and e- I band shorten
  • identify the parts of the sarcomere.
    a: actin myofilament, b: myosin myofilament, c: H zone, d: A band, e: I band, f: z disk
  • What does acetylcholine do, and where does it do it?
    It is released by the presynaptic terminal, and travels across the synaptic cleft, to establish an action potential on the membrane of the muscle cell
  • What is happening when the Ca+ is decreasing in the sarcoplasmic reticulum?
    Ca+is going into the sarcomere to attach to the troponin to pull it away from the binding sites on the actin so the moyosin can attach to begin the contraction.
  • identify a, b, c, d, e in the figure
    a: epimysium, b: perimysium, c: endomysium, d: muscle cell(fiber), e: fascicle,
  • What causes rigor mortis?
    moving Ca into the sarcoplasmic reticulum requires energy (low to high concentration) so,Ca leaks into the muscles......
  • When you see the ending "ase" what does that mean?
    it is an enzyme, Acetylcholinesterase, (ACh) it breaks down Acetylcholine. Enzymes are names for the thing they act upon
  • What does it mean when a motor neuron is recruited?
    motor neuron is recruited: it is responding to a stimulus by sending action potentials down its axon.
  • What gives us muscle tone?
    Partial contraction of a muscle -When only some of the motor units are recruited
  • What is a sarcomere?
    sarcomere: the repeating unit of a myofibril
  • What does acetylcholine do?
    Neurotransmitter, allows an action potential to cross the synaptic cleft.
  • name and describe the 3 types of muscle tissue, including shape and nucleus.
    Skeletal, cardiac and smooth
  • Identify structures of the neuromuscular junction a, b, c, d and e
    A presynaptic terminal, B mitochondria, C synaptic vesicle, D synaptic cleft, E postsynaptic membrane
  • Why do you still breathe hard when you have finished exercising?
    1. aerobic respiration, 2. converting lactic acid to glucose 3. converting lactic acid to creatine phosphate to replenish the energy reserve
  • Why do muscles come in pairs? (Agonist and Antagonist)in terms of how muscles contract.
    When the myosin head releases from the actin, it is easy to stretch out,it doesn't automatically.The antagonist muscle can return it to original size or gravity
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