4.3.6 - Controlling the heart Flashcards
What is the equation for cardiac output?
Stroke volume x Heart rate
What does the sinoatrial node do first?
Sets up a wave of depolarisation which causes the atria to contract
Why can’t the wave of depolarisation spread straight to the ventricles?
There is non-conducting tissue between atria and ventricles. (Annulus fibrosus)
Where does the wave of depolarisation spread to?
The atrioventricular node.
After spreading to the atrioventricular node, where does the wave of depolarisation go?
Spreads down the bundle of His
(conducting fibres in septum)
What happens after the wave of depolarisation spreads through the bundle of His?
Moves onto purkyne tissue
What does the electrical signal cause?
The ventricles to contract from the apex upwards
When do valves close?
When the pressure of the blood in front of them is greater than behind them.
This prevents backflow of blood
What do the region of non-conducting tissue between atria and ventricles prevent?
Excitation
