Cardiac Conduction system Flashcards
What does myogenic mean?
The capacity of the heart to generate its own impulses
What is the correct order that the impulse travels in?
SAN, Atrial Systole, AVN, Bundle of HIS, Purkinje Fibres, Ventricular Systole
What is the diastole phase?
The heart is relaxing and filling with blood, the atria fill with blood and pressure builds, as the pressure builds the valves begin to slowly open and small amounts of blood are let through
What is the atrial systole phase?
The valves are now forced open, both atria contract and the remaining blood is forced into the ventricles
What is the ventricular systole phase?
Blood is now in the ventricles, the ventricles contract which increases the pressure. The aortic valve and the pulmonary valve are forced open, which allows blood to be pushed through either the aorta or the pulmonary artery
How does the heart know to speed up?
The ANS determines the rate at which the SA ( sinoatrial) node sends out impulses
How does the heart speed up?
Increases HR by releasing adrenaline.
- Adrenaline increases the strength of ventricular contraction which increases SV
- Noradrenaline aids the spread of electrical impulses throughout the heart increasing HR.
- This results in an increased cardiac output
What does adrenaline do?
Adrenaline increases the strength of ventricular contraction which then increases stroke volume.
What does noradrenaline do?
Noradrenaline aids the spread of electrical impulses throughout the heart increasing HR.
What does acetylcholine do?
Acetylcholine slows the rate of the spread of impulses throughout the heart
What is Starling’s law?
Starling’s law states that if venous return increases then stroke volume increases due to more blood filling the atria and ventricles which leads to increased injection fraction of blood
