cardiac control Flashcards
what is the CCC
the cardiac control centre
where is the CCC located
medulla oblongata
what is the CCC responsible for
regulating the heart
what is controlling the CCC
the Autonomic Nervous System (ANS).
The ANS is under involuntary control.
what does the ANS consist of
the ANS consists of sensory and motor nerves from either the sympathetic or parasympathetic nervous system.
is cardiac control sympathetic or parasympathetic
both
what does the Sympathetic nervous system (SNS)
increase HR
what does the parasympathetic NS do
decreases HR (by blocking activity of the sympathetic nervous system).
During exercise, the CCC (in medulla oblongata) receives feedback from 3 main receptors. what are they
proprioceptors, barorecptors and chemoreceptors
what nerve increases HR
accelerator nerve
what nerve decreases HR
vagus nerve
what are proprioceptors and where are they
Proprioceptors are sensory receptors in muscles, tendons and joints that detect changes in motor movement
what do proprioceptors do if they detect a change
increase HR
what are chemoreceptors and where are they located
Sensory receptors that detect chemical changes in the muscles, aorta and carotid arteries.
what do chemoreceptors detect
an increase in lactic acid and CO2 levels
a decrease in O2 and PH levels (acidity)
what do chemoreceptors do if they detect a change
increase HR
what are baroreceptors and where are they located
Sensory stretch receptors within blood vessel walls, the aortic and carotid arteries.
They inform the CCC that blood pressure has increased
what happens if their is an increase in blood pressure
the baroreceptors detect it and decrease HR
During exercise there are a number of intrinsic (internal) factors that affect Heart Rate. what are they
- Temperature Increases:
Increase in temperature
= Increase SA node firing rate
= Increase in HR
= Increased O2 delivery - Starling’s Law:
Increase in venous return
= increased SV & increased Q
what type of control are thermoreceptors
intrinsic
what do thermorecpetors do
Detect changes in temperature in the blood.
They increase or decrease HR accordingly.
what happens if your blood temp has gone down
thermorectors detect this and HR slows
what is the 1 hormonal control
adrenaline
what does adrenaline do
Adrenalin stimulates the SA node to increase HR
Adrenaline increases strength of ventricular contraction = increase in stroke volume.
what cause pre-anticipatory rise
adrenaline
what happens to regulation during exercise
During exercise, receptors detect changes and send signals to the SNS
sympathetic takes over
This in turn sends messages to the SA node via accelerator nerves, which release adrenaline, increasing HR.
what system is in control at rest
parasympathetic
what happens after exercise
Once exercise finishes, the parasympathetic nervous system takes over again
Messages are sent to the SA node via the vagus nerve.
The PNS releases acetylcholine, reducing HR
Temperature decreases and Heart Rate decreases
Venous return decreases, which in turn decreases stroke volume
