The control and regulation of the heart Flashcards
(26 cards)
What does the autonomic nervous system do?
Determines the rate at which the SA node sends impulses.
What is the sympathetic nervous system responsible for?
Increasing the hart rate during exercise.
What is the parasympathetic nervous system responsible for?
Returning the heart and respiratory rate back to normal resting levels during exercise.
Where is the cardiac control centre?
In the medulla oblongata.
What does the CCC control?
The heart rate
How does the sympathetic nervous system increase heart rate?
It releases adrenaline.
What does noradrenaline do?
Aids the spread of the impulse through the heart.
When adrenaline is released it also increases the stroke volume. Why is this?
The adrenaline increases the strength of the ventricle contractions and therefore the stroke volume increases because more blood is being forced out.
What does the parasympathetic nervous system release to decrease the heart rate?
Acetylcholine.
What does acetylcholine do?
It slows down the impulses in the heart.
What are the three main factors that determine the action of the CCC?
Neural factors
Hormonal factors
Intrinsic factors
What ‘receptors’ are involved in the neural factors?
Proprioreceptors/Mechanoreceptors
Chemoreceptors
Baroreceptors
What do proprioreceptors do?
They relay the amount of movement in the muscles to the CCC.
What happens when the proprioreceptors detect movement?
It tells the CCC that they require a higher amount of oxygen in order to respire.
What do chemoreceptors detect?
Changes in the pH of the blood.
Where are chemoreceptors?
In the aorta.
Where are proprioreceptors found?
In the muscles.
What do the chemoreceptors tell the CCC to do?
To increase the heart rate to remove CO2 faster so that the blood pH returns to normal.
What do baroreceptors detect?
Changes in blood pressure.
Which hormones are involved in the hormonal factors of the CCC?
Adrenaline and noradrenaline.
Adrenaline and noradrenaline increase the strength of contraction of the ventricles but they also….
Assisst the redistribution of blood through vasoconstriction and vasodilation.
What increases in the body in terms of intrinsic factors?
Increase in body temperature during exercise.
Increase in blood viscosity/ability to travel around the body.
Raises heart rate by an increase in speed of nerve impulse transmission.
At rest which nervous system is in control?
The parasympathetic nervous system.
An increase in metabolic activity causes what?
Increase in the concentration of lactic acid and CO2.
A decrease in blood pH.
