14.6 Controlling Heart Rate Flashcards
What system is heart rate controlled by?
Autonomic nervous system
Where in the brain is heart rate controlled?
Medulla oblongata
How many centres does the medulla oblongata have?
2
How is heart rate increased (in autonomic nervous system)?
Medulla oblongata sends impulses along the sympathetic nervous system (via the accelerator neurone) to the SAN which increases heart rate
How is heart rate decreased (in autonomic nervous system)?
Medulla oblongata sends impulses along the parasympathetic nervous system (via the vagus neurone) to the SAN, which decreases the heart rate.
What hormone slows heart rate?
Acetyl choline
Which hormones increases heart rate?
Adrenaline and noradrenaline
What two types of receptors provide information that effect heart rate?
Chemoreceptors
Baroreceptors
What do chemoreceptors detect?
Changes in levels of a chemical in the blood.
Where are chemoreceptors located?
Aorta, medulla, and carotid artery
If carbon dioxide levels increase in the blood, then the pH…?
Decreases
Why does the blood become more acidic if carbon dioxide levels increase?
Carbonic acid is formed (by the carbon dioxide reacting with the water in the blood).
If there is a high concentration of carbon dioxide in the blood, does the heart rate increase or decrease and why?
Increase, to pump carbon dioxide to lungs, so it can be exhaled.
What do baroreceptors detect?
Changes in blood pressure
Where are baroreceptors located?
Aorta, vena cava, carotid arteries
