Electrical activity of the heart Flashcards
Electrical activity of the heart
Stages of refractory peroid in cardiac muscle cells
Absolute refractory peroid
Relative refractory peroid
Electrical activity of the heart
Stages of action potential in cardiac action potential
Rapid depolarisation
The plateau
Repolarisation
Electrical activity of the heart
Rapid depolarisation in cardiac cells
Caused by Na+ influx
Stops when voltage-regulated Na+ channels close
Electrical activity of the heart
The plateau in the cardiac action potential
Caused by Ca2+ influx
Ends when slow calcium channels close
Electrical activity of the heart
Repolarisation in the cardiac action potential
Caused by the efflux (loss) of K+ ions
Ends when slow K+ channels close
Electrical activity of the heart
Why does the refractory peroid in cardiac muscle cells last so long?
So it doesn’t cause summation
Spaced out muscle contraction
Electrical activity of the heart
Order of conduction of the action potential through the heart
Electrical activity of the heart
ECG - Diagram and points
Electrical activity of the heart
P wave
Depolarisation of the atria
Electrical activity of the heart
QRS complex
Depolarisation of the ventricles
Electrical activity of the heart
T wave
Repolarisation of the ventricles
Electrical activity of the heart
RR interval (ECG)
Used to calculate heart rate
Electrical activity of the heart
PR interval
Indicates conduction from the SA node to the ventricles
Electrical activity of the heart
QT interval
Ventricular depolarisation and repolarisation
Electrical activity of the heart
Cardiac muscle source of intrecellular Ca2+
Sarcoplasmic reticulum
Axtracellular fluid
