Controlling heart rate Flashcards
How can the heart be modified
- Change heart rate (bpm)
- The contraction strength of the ventricles
- Changing the volume of blood transported per stroke
How is the heart modified
Innervation - by nerves from the sympathetic and parasympathetic nervous systems
What does it mean that the heart muscle is myogenic
It can contract by itself
What is heart rate controlled by
Sinoatrial node
Where do the nerves that modify the heart come from
Cardiac control centre in the medulla oblongata
What is the accelerans nerve
The sympathetic nerve contacting the sinoatrial node
How does the accelerans nerve affect the heart
It releases the neurotransmitter adrenaline which increases heart rate
What is the vagus nerve
The parasympathetic nerve contacting the heart
How does the accelerans nerve affect the heart
Releases acetylcholine and causes heart rate to slow
Describe chemoreceptors
They are found in the carotid arteries and the aortic arch. They measure the pH of the blood
What happens to CO2 levels in the blood when we exercise
they increase
What does the CO2 do when it is in the blood
It reacts with water to produce carbonic acid, which lowers the pH
What happens when chemoreceptors detect a decrease in pH
They send an impulse to the CCC which causes the accelerans nerve to send more frequent impulses
What does faster heart rate do to CO2 levels
Faster heart rate results in more CO2 being transported to the lungs to be removed so less CO2 will be in the blood so chemoreceptors will be less stimulated and the heart rate will slow
What is the action of chemoreceptors an example of
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