Function of Myocardial cells - Conduction system and conduction of impulses
3 important questions on Function of Myocardial cells - Conduction system and conduction of impulses
How do action potentials get conducted in the heart?
- SA node - pacemaker
- AV node
- AV bundle (Bundle of His)
- Purkinje fibres
- Ventricular muscle
Where do action potentials originate from?
SA node (pacemaker), it has the greatest sodium permeability and potassium permeability declines during diastole. RMP is -55mV. Has funny sodium channels that leak sodium, and have T type Ca2+ channels that open as membrane gets closer to threshold, K+ channels allowing K+ outflow, allowing it to be self-excited and repolarized
What affects SA node discharge rates?
- Slope of the pre-potential (diastolic depolarization)
- Threshold for discharge of the action potential
- Change the RMP (level of diastolic repolarization)
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