1)Increasing sarcoplasmic Ca2+ binds to MLCK directly. True or False?
2) Increasing sarcoplasmic Ca2+ decreases the activity of MLCP. True or False?
3)Activation of a pathway that generates IP3 will: (more than one answer could be correct)
a.Open IP3 channels on SR which releases Ca2+, leading to smooth muscle contraction.
b.Activation of cAMP, which inhibits contraction.
c.Leads to greater influx of Na+ through voltage-gated Na+ channels, increasing contraction.
d.Inhibition of MLCP activity, increasing the relative amount of MLCK in the cell, leading to contraction.
4)Increasing intracellular cAMP leads to smooth muscle relaxation by:
a.inhibiting IP3 channels, leading to decreased Ca2+ in the sarcoplasm and reduced contraction.
b.Activating K+ channels, increasing K+ leaking out of the cell which hyperpolarizes it and decreases the likelihood of Ca2+ entry.
c.Increasing the relative activity of MLCP, leading to a decrease in tension.
d.Lower levels of MLCK, leading to decreased contraction.
5)If, or "funny channels", are:
a.Voltage-gated, and therefore activated by depolarization.
b.Voltage-gated, and activated by hyperpolarization
c.Permit passage of both K+ and Na+, although the actions of Na+ dominate.
d.Act to depolarize the membrane.
6) Pacemaker cells of the SA and AV node do not have a Na+ component to their action potentials. True or False?
1)Increasing sarcoplasmic Ca2+ binds to MLCK directly. True or False?
2) Increasing sarcoplasmic Ca2+ decreases the activity of MLCP. True or False?
3)Activation of a pathway that generates IP3 will: (more than one answer could be correct)
a.Open IP3 channels on SR which releases Ca2+, leading to smooth muscle contraction.
b.Activation of cAMP, which inhibits contraction.
c.Leads to greater influx of Na+ through voltage-gated Na+ channels, increasing contraction.
d.Inhibition of MLCP activity, increasing the relative amount of MLCK in the cell, leading to contraction.
4)Increasing intracellular cAMP leads to smooth muscle relaxation by:
a.inhibiting IP3 channels, leading to decreased Ca2+ in the sarcoplasm and reduced contraction.
b.Activating K+ channels, increasing K+ leaking out of the cell which hyperpolarizes it and decreases the likelihood of Ca2+ entry.
c.Increasing the relative activity of MLCP, leading to a decrease in tension.
d.Lower levels of MLCK, leading to decreased contraction.
5)If, or "funny channels", are:
a.Voltage-gated, and therefore activated by depolarization.
b.Voltage-gated, and activated by hyperpolarization
c.Permit passage of both K+ and Na+, although the actions of Na+ dominate.
d.Act to depolarize the membrane.
6) Pacemaker cells of the SA and AV node do not have a Na+ component to their action potentials. True or False?
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