Variations in Heart Rate

Question 1

Where is the cardiovascular control centre located?

Answer 1

The medulla oblongata

Question 2

State the function of the cardiovascular control centre.

Answer 2

Controls heart rate

Question 3

What are baroreceptors?

Answer 3

Pressure receptors that detect changes in blood pressure

Question 4

What are chemoreceptors?

Answer 4

Chemical receptors that detect chemical changes (oxygen & carbon dioxide concentration & pH levels) in the blood.

Question 5

What happens if high blood pressure is detected?

Answer 5

1. Baroreceptors send impulses along the parasympathetic nervous system
2. This triggers the secretion of acetylcholine, which bind to receptors on the SAN
3. SAN fires less frequent impulses to slow heart rate and reduce blood pressure

Question 6

What happens if low blood pressure is detected?

Answer 6

1. Baroreceptors send impulses along the sympathetic nervous systems
2. This triggers the secretion of noradrenaline, which binds to receptors on the SAN
3. SAN fires more frequent impulses to increase heart rate and blood pressure

Question 7

What happens if high concentrations of carbon dioxide, and therefore low pH levels, are detected?

Answer 7

1. Chemoreceptors send impulses along the sympathetic nervous system
2. This triggers the secretion of noradrenaline, which binds to receptors on the SAN
3. SAN fires more frequent impulses to increase heart rate and remove more carbon dioxide.

Question 8

What happens if high concentrations of oxygen, and therefore low pH levels, are detected?

Answer 8

1. Chemoreceptors send impulses along the parasympathetic nervous system
2. This triggers the secretion of acetylcholine, which binds to receptors on the SAN
3. SAN fires less frequent impulses to decrease heart rate