Prep for USMLEPrep for USMLE
         Forum      |     Resources New Posts   |   Register   |   Login





 cardio ? -please explain  



Post Reply  
  • 0/5
  • 1
  • 2
  • 3
  • 4
  • 5


Author4 Posts
  #1

If you reduced the outward current in a heart cell, what would be the result?

A. Increase the rate of repolarization.
B. Prolong the action potential.
C. Increase the rate of depolarization.



...... i thought the answer was c but is b... can someone explain. the outward current is established by the flow of potassium outside of the cell. right? so if potassium doesn't flow out wouldn't it make the cell more positive and increase the rate of depolrization?




  #2

it will prolong the action potential of the heart cell by blocking the potasssium channels, prolong the phase 1 and 3 of the action potential actually, due to the prolong of the refractory phase, it will decrease the heart rate and decrease the depolization rate of the heart.
you may correlate this with anti-arrythemic drugs and will realize it.


  #3

yes it should be B


  #4

okay... i understand now. :P





Bookmark and Share



This thread is closed, so you cannot post a reply.



Login or Register to post messages








show Similar forum topics

cardio Q plz someone explain it! I'll post answer
please explain
Please explain
show Related resources









Advertise | Support | Premium | Contact