control of the heart rate Flashcards
(21 cards)
What is the heart rate?
Myogenic
What does this mean?
Beats with its own rhythm
When does heart rate increase?
During exercise
What does this do?
Increases blood flow to the muscles, bringing in more oxygen and glucose and rid of CO2
What does the sinoatrial node act as?
A pacemaker
Where is it located?
Right atrium
What does it produce?
Regular waves of electrical activity
Where do these impulses go?
Through the walls of the right and left atrium
What does this cause?
The atrium to contract together
Where do the impulses go next?
Atrioventricular node
What happens before the AVN contracts?
There is a delay
What does this ensure?
There is no blood left in the atria and the ventricles are full of blood and contract after the atria
Where do the impulses from the AVN go?
Through the bundle of His and the Purkyne tissues
What does this cause?
The ventricles contract together
Which part of the nervous system controls the heart rate?
Autonomic nervous system
Where does this centre?
The medulla
How do the sympathetic and parasympathetic nervous systems work?
Antagonistically
How is the heart rate sped up?
Medulla sending more impulses via sympathetic neurones to the SAN
What neurotransmitter is released?
Noradrenaline
How is the heart rate slowed down?
Medulla sending more impulses via parasympathetic neurones to the SAN
What is the neurotransmitter released?
Acetylcholine
