6.5 PEx: Cardiovascular Physiology Lab Part 2

Part A

Which ion(s) at least initially lowered the frog heart rate in the activity you just performed?
    potassium
    calcium, potassium and sodium
    sodium
    potassium and sodium
    calcium

Part B

What effect does potassium have on the resting membrane potential of the cardiac cell?
    Increasing extracellular potassium causes the resting membrane potential to become more negative.
    Increasing intracellular potassium causes the resting membrane potential to become more positive.
    Changes in potassium have no effect on the resting membrane potential.
    Increasing extracellular potassium causes the resting membrane potential to become more positive.

Part C

The cardiac cell plasma membrane is most permeable to _______________________.
    potassium
    It is equally permeable to all ions.
    calcium
    sodium

Part D

Calcium channel blockers block the movement of calcium _______.
    into the cell and decrease heart rate
    into the cell and increase heart rate
    out of the cell and increase heart rate
    out of the cell and decrease heart rate

Part E

A ___________________ drug increases the force of contraction of the heart.
    negative chronotropic
    positive inotropic
    positive chronotropic
    negative inotropic