Short Term Control of BP Flashcards
What is the baroreflex responsible for?
Maintenance of arterial blood pressure
How many sets of baroreflexes do we have?
2
Where can you find the baroreflexes?
Aortic arch
Carotid sinuses
What do the aortic arch and carotid sinuses have in common?
Both stretchy
How do the baroreceptors detect changes in pressure?
When pressure increases, the walls stretch and baroreceptors detect that change in stretch and they increase the firing rate of action potentials.
What happens to the firing rate of action potentials when pressure increases?
Firing rate increases
What happens to the firing rate of action potentials when pressure decreases?
Firing rate decreases
When are the aortic arch and carotid sinuses stretched the most?
During systole as there is an increase in pressure.
Where do the aortic arch baroreceptors send their signal?
Up the Vagus nerve
Where do the carotid sinuses send their signals?
Up the glossopharyngeal nerve.
Where are the integrating centres known as the medullary cardiovascular centres located?
Medulla oblongata
Name some of the responses that the medullary cardiovascular centres can evoke to bring MAP back to where it should be.
Parasympathetic outflow via vagus nerve
Sympathetic nerves
Which neurotransmitter is released in a parasympathetic response?
Acetyl choline
Where does acetyl choline bind to?
Cholinergic muscarinic receptors on the pacemaker cells.
What will happen when acetyl choline binds to the cholinergic muscarinic receptors on the pacemaker cells?
Cause them to hyperpolarise and will take them longer to reach threshold therefore decreasing HR.