Controlling heart rate Flashcards Preview

Biology unit 5 > Controlling heart rate > Flashcards

Flashcards in Controlling heart rate Deck (18)
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1
Q

How can the heart be modified

A
  • Change heart rate (bpm)
  • The contraction strength of the ventricles
  • Changing the volume of blood transported per stroke
2
Q

How is the heart modified

A

Innervation - by nerves from the sympathetic and parasympathetic nervous systems

3
Q

What does it mean that the heart muscle is myogenic

A

It can contract by itself

4
Q

What is heart rate controlled by

A

Sinoatrial node

5
Q

Where do the nerves that modify the heart come from

A

Cardiac control centre in the medulla oblongata

6
Q

What is the accelerans nerve

A

The sympathetic nerve contacting the sinoatrial node

7
Q

How does the accelerans nerve affect the heart

A

It releases the neurotransmitter adrenaline which increases heart rate

8
Q

What is the vagus nerve

A

The parasympathetic nerve contacting the heart

9
Q

How does the accelerans nerve affect the heart

A

Releases acetylcholine and causes heart rate to slow

10
Q

Describe chemoreceptors

A

They are found in the carotid arteries and the aortic arch. They measure the pH of the blood

11
Q

What happens to CO2 levels in the blood when we exercise

A

they increase

12
Q

What does the CO2 do when it is in the blood

A

It reacts with water to produce carbonic acid, which lowers the pH

13
Q

What happens when chemoreceptors detect a decrease in pH

A

They send an impulse to the CCC which causes the accelerans nerve to send more frequent impulses

14
Q

What does faster heart rate do to CO2 levels

A

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

15
Q

What is the action of chemoreceptors an example of

A

Negative feedback

16
Q

Where are baroreceptors located

A

In the carotid arteries and the aortic arch

17
Q

What happens in baroreceptors detect low pressure

A

They transmit signals to the CCC which triggers accelerans nerve of the sympathetic system to increase heart rate and pressure

18
Q

What happens in baroreceptors detect high pressure

A

They transmit signals to the CCC which triggers vagus nerve of the parasympathetic system to decrease heart rate and pressure