action potentials in heart

[Tina324]

Hi guys,

I am a little confused about 1) which cells in the heart can conduct action potentials and 2) what path do the action potentials take during a cardiac cycle? Do the pacemaker cells in the SA node send action potentials to myocardial cells in the atrium which lead into the AV node? Then where do the conducting cells come into play?

From my understanding, there are 3 types of cardiac cells
1. mayocardial
2. pacemaker cells
3. conducting cells

Please someone...help! lol

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[Albuterol]

http://forums.studentdoctor.net/showthread.php?t=547353&highlight=SA+node

check out this thread..i had the same question but it was answered very thoroughly!

 

[doc3232]

SA node sends a signal that forces atria to contract and a delayed signal to the AV node to contract.
SA node is located in the top of the right atria, and the AV node is loacted between the ventricles, which spreads through Bindle of His and Punjabi fibers or something...correct me if I am wrong.

 

[yakuza]

SA node sends a signal that forces atria to contract and a delayed signal to the AV node to contract.
SA node is located in the top of the right atria, and the AV node is loacted between the ventricles, which spreads through Bindle of His and Punjabi fibers or something...correct me if I am wrong.

Its pretty much right except the av node doesn't contract

spontaneous initiation ---> SA node --signals--> both atria contract simultaneously, fill with blood, and then contract

THEN SA node --delayed signal--> AV node --signal--> bundle of his --signals--> purkinje fibers --> make both ventricles contract