Control Of Heart Rate Flashcards
What does the SA mode send impulses across?
The atria
When impulses pass across the cardiac muscle what does this cause?
Muscle contraction (increasing the pressure)
Why is impulse delayed at AV node?
To give time for the atria to empty completely of blood before ventricles contract
What prevents the atria and ventricles from contracting at the same time?
A layer of non conducting tissue
Describe the passage of impulses from the AV node to cause ventricles to contract
Down the bundle of His to the apex of the heart then around the purkyne fibres
What type of receptions detect a change in pH and what causes that change in pH?
Chemoreceptors. pH change caused by increase or decrease of carbon dioxide in blood
What type of receptors detect a change in blood pressure?
Baroreceptors
Where are the receptors found?
Aortic arch (aorta) and carotid artery
Where in the brain do these receptors send impulses to?
Medulla
Which pathway does the medulla send impulses down to decrease heart rate and what neurotransmitter does this release to the SA node?
Parasympathetic pathway releasing acetylcholine
Which pathway does the medulla send impulses down to increase heart rate and what neurotransmitter does this release to the SA node?
Sympathetic pathway releasing noradrenaline
What happens to the frequency of impulses sent from the SA node to increase heart rate?
Increases causing heart to contract more frequently and increasing heart ratw