14.6 controlling heart rate

Carotid artery

The blood vessel that carries oxygenated blood to the head brain and face

What’s the cardiac cycle controlled by

Myogenic muscle in the walls of the atriums

What’s the heart rate controlled by

The autonomic nervous system

Which part of the brain controls the heart rate

Medulla oblangata

What does the sympathetic nervous system do to the heart rate?

Increase it

What does the parasympathetic system do to the heart rate?

decrease it

What happens if the blood pressure is too high?

Impulses are send to the medulla oblangata which decreases heart rate. The medulla oblongata sends impulses along the parasympathetic neurones to the SAN which decreases the heart beat and reduces blood pressure

What happens if blood pressure is too low?

Impulses are sent to the medulla oblangata which increases heart rate. The medulla oblangata sends impulses along along the sympathetic neurones which increases the rate at which the heart beats, increasing blood pressure

What happens if the carbon dioxide levels in the blood increase?

PH will decrease because carbonic acid is formed when carbon dioxide interacts with water in the blood. The medulla oblangata sends impulses along the sympathetic neurones which increase the rate at which the heart beat. Blood flows more quickly to the lungs so it can be exhaled

What happens if carbon dioxide level decreases?

PH increases which is detected by chemoreceptors in the carotid arteries and aorta causing less impulses being sent to the medulla oblangata which sends less impulses to the SAN along the sympathetic neurones which decreases the heart rate