Cardiac & Smooth Muscles

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  1. Like skeletal muscles, cardiac muscles are also __. Cells are __ than skeletal muscle and have __ nucleus
    striated; smaller; one

    Cardiac muscles also branch and interdigitate - can withstand high pressures.
  2. __ and __ cells initiate & coordinate heart contractions.
    Pacemaker; conducting
  3. The heartbeat is __ - generated by the heart muscle itself.
  4. The ANS modifies the __ of pacemaker cells, but is not necessary for their function.
  5. Smooth muscle is in most internal organs and is under __ control.

    Neural influences on smooth muscle come from ANS
  6. __ cells are arranged in sheets - have electrical contact via gap junctions.
    Smooth muscle

    Action potential in one cell can spread to all others in the sheet.
  7. __ in digestive tracts cause __, causing contraction. __ causes the same cells to __, leading to fewer contractions.
    • ACh; depolarization & action potentials;
    • NE; hyperpolarize

    ANS neurotransmitters can alter membrane resting potentials & affect the rate at which smooth muscle fire action potentials, thus controlling smooth muscle contraction.

    (page 57 on slide)
  8. Smooth muscle contraction:__ influx to sarcoplasm is stimulated by stretching, action potentials or hormones.
  9. Smooth muscle contraction: Ca2+ binds with __, which activates __, which phosphorylates __, which then can bind & release __
    • calmodulin;
    • myosin kinase;
    • myosin heads;
    • actin
  10. smooth muscle contraction story
    • Ca2+ entering sarcoplasm binds & activates calmodulin.
    • Activated calmodulin activates myosin kinase, which phosphorylates myosin heads (ATP to ADP)
    • Phosphate group attaches to myosin head.
    • Myosin head binds to actin.

    (page 59 on slide)
  11. __ causes the myosin head to unbind from actin.
    Myosin phosphatase

    Phosphate group is no longer attached to myosin.

    (page 59 on slide)
Card Set:
Cardiac & Smooth Muscles
2016-11-16 21:30:37
muscles cardiac smooth

Week 6
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