Cardiovascular System Flashcards
What is the Myocardium???
It is a interlacing bundle of cardiac muscle fibres surrounding the heart
What are the 3 components of the wall of the heart???
Myocardium which is the muscular component of the heart.
Endocardium which is the inner walling of the myocardium.
Epicardium which forms the inner wall pericardial sac (outer wall of myocardium).
What are the 2 phases of the cardiac cycle???
Systole phase which is the contraction phase.
Diastole phase which is the relaxation phase.
What is the normal average time for the cardiac cycle???
0.7 - 0.8 seconds
What is each contraction dependant upon???
The action potential (AP) sweeping across the muscle cell membranes.
What is the ECG complex???
A combination of the PQRSTU wave. Each letter relates to a part of the cardiac cycle.
The complex represents the depolarization of ventricles.
Why the QRS complex varies
between leads???
When an electrical impulse flows towards the electrode it produces a positive or upwards deflection.
When an electrical impulse flows away from the electrode it produces a negative or downwards deflection.
What heart rate is fast and slow???
100bpm = fast
50bpm = slow
What are the factors that affect conduction???
- Resting Membrane Potential
- Depolarization
- Repolarization
- Action Potential
- Automaticity
- Excitability and Conductivity
- Electrolytes
- Nervous Innervation
- Drugs
