Beating Faster Flashcards
Myogenic means that it does not need…
Stimulation by a nerve to make it contract
The heart muscle is…
Myogenic
The cardiac cycle starts when impulses are generated by the…
Sinoatrial nose (SAN) in the wall of the right atrium
The nervous system can change the rate at which the heart beats due to the medulla which contains a region called the …
Cardiovascular centre
The cardiovascular centre receives impulses from…
Various receptors in the body
HR is increased when…
Carbon dioxide builds up
Exercise = muscle cells respire more and produce more CO2 which…
Lowers the pH
Fall in pH is detected by chemoreceptors in the:
medulla, carotid body and aortic bodies
Chemoreceptors send impulses along…
Sensory nerves to the cardiovascular centre in the media
Result of impulses along sensory nerves to CV centre = more impulses are passed along the…
Sympathetic nerve from the CV centre to the SAN
Sympathetic never stimulated the…
SAN to send out more frequent impulses = increasing HR
When CO2 levels fall- chemoreceptors detect this and send send impulses to the…
CV centre in the medulla
Decrease in CO2 = more impulses sent along the…
Parasympathetic nerve to the SAN = slowing HR
Blood pressure increases during exercise as the body muscles contract…
More strongly
Blood pressure increase, increases the rate at which deoxygenated blood returns to the heart in the…
Venae cavae
Due to the increase in deoxygenated blood returning to the heart in the venae cavae the walls are:
Stretched by this increasing blood flow = heart rate increases
The increased vole of blood stretches the heart muscle, resulting in the heart muscle…
Contraction more strongly during systole = pumping out more blood each time it contracts
The volume of blood pumped out by the heart during one beat =
Stroke volume
Volume of blood pumped out by the heart in one minute =
Cardiac output
Stroke volume x heart rate
The increased stroke volume stretches the walls of the…
Aorta and carotid arteries
Pressure receptors are in the…
wall of the aorta and carotid sinus in the carotid artery
The pressure receptors in the wall of the aorta and carotid sinus detect stretching and…
Send impulses to the CV centre in the medulla
As a result of the impulses from the pressure receptors in the aorta wall and carotid sinus to the CV centre, more impulses are sent along the…
Parasympathetic nerve to the SAN, slowing HR
Carotid body =
Chemoreceptors (blood pH)
Carotid sinus =
Pressure receptors (blood pressure)
