1.1 Cardiac action potential Flashcards
What specialisation allows the action potential conduction between cells?
Gap junctions
What are the cells of the impulse conducting system?
SA node, AV node and purkinje fibres
What are the 5 phases of the cardiomyocyte action potential
- fast depolarization
- early repolarization
- Plateau
- final repolarization
- resting membrane potential
What causes phase 0 in cardopmyocytes
Activation of Fast Na and suppression of K channels`
What causes phase 1 of the AP in cardiomyocytes
Inactivation of fast Na and activation of fast K channels
What causes phase 2 of the AP in cardiomyocytes
Ca++ channels open slow K channels open
What causes phase 3 of the AP in cardiomyocytes
K+ out (ks kr k1)
Inactivation of Ca
What is the propagation speed of APs in cardiomyocytes dependent on?
Gap junction conductance and fibre diameter
the larger the faster for both
What are the three phases of the action potential in impulse conduction cells
- depolarisation (CALCIUM not sodium)
- repolarisation
- Variable RMP
What is the phase 0 spike in impulse conduction cells due to?
Calcium spike
What causes phase 3 in impulse conduction cells?
Inactivation of Ca channels and activation of K channels
What causes phase 4 in impulse conduction cells?
Na and Ca in
