PE PAPER 1
Anatomy and physiology
Cardiovascular system
Conduction system
when we start exercising, there is movement is the muscles and joints, CO2
produced, blood pressure increases, and temperature
increases.
mechanoreceptors: movement in muscles
proprioceptors: movement in joints
chemoreceptors: CO2
baroreceptors: blood pressure
thermoreceptors: temperature
the receptors send information to the brain (medulla
oblongata)
in the medulla is the cardiac control centre (CCC). CCC receives info and decides to
speed up/slow down HR.
speeds up HR: sympathetic nervous system —> sympathetic nerve
slows down HR: parasympathetic nervous system —> vagus nerve
all that information then gets sent to the heart
all info goes to SA node.
the signal spreads over the atria, the atria contracts (atrial systole).
AV node is delayed by 0.1secs so atria can fully contract.
signal travels down septum via bundles of HIS, then spreads around ventricle via
purkinje fibres.
ventricle contracts.
Adrenaline
release of adrenaline during exercise is known as hormonal control.
adrenaline = stress hormone that’s released by sympathetic nerves and cardiac
nerves during exercise.
adrenaline stimulates SAN, so increase in heart rate, increases cardiac output.
Stroke volume
stroke volume: volume of blood pumped from heart per ejection
SV depends on…
venous return: volume of blood returning to heart via veins. if VR increases, SV
increases.
elasticity of cardiac fibres: degree of stretch of cardiac tissue during diastole. more
stretch, greater force of contraction, increased ejection fraction.
starlings’ law: increased VR —> greater diastole filling of heart —> cardiac muscle
stretched —> more contraction force —> increased ejection fraction
ejection fraction = stroke volume / end diastolic volume
SV in response to exercise…
Anatomy and physiology
Cardiovascular system
Conduction system
when we start exercising, there is movement is the muscles and joints, CO2
produced, blood pressure increases, and temperature
increases.
mechanoreceptors: movement in muscles
proprioceptors: movement in joints
chemoreceptors: CO2
baroreceptors: blood pressure
thermoreceptors: temperature
the receptors send information to the brain (medulla
oblongata)
in the medulla is the cardiac control centre (CCC). CCC receives info and decides to
speed up/slow down HR.
speeds up HR: sympathetic nervous system —> sympathetic nerve
slows down HR: parasympathetic nervous system —> vagus nerve
all that information then gets sent to the heart
all info goes to SA node.
the signal spreads over the atria, the atria contracts (atrial systole).
AV node is delayed by 0.1secs so atria can fully contract.
signal travels down septum via bundles of HIS, then spreads around ventricle via
purkinje fibres.
ventricle contracts.
Adrenaline
release of adrenaline during exercise is known as hormonal control.
adrenaline = stress hormone that’s released by sympathetic nerves and cardiac
nerves during exercise.
adrenaline stimulates SAN, so increase in heart rate, increases cardiac output.
Stroke volume
stroke volume: volume of blood pumped from heart per ejection
SV depends on…
venous return: volume of blood returning to heart via veins. if VR increases, SV
increases.
elasticity of cardiac fibres: degree of stretch of cardiac tissue during diastole. more
stretch, greater force of contraction, increased ejection fraction.
starlings’ law: increased VR —> greater diastole filling of heart —> cardiac muscle
stretched —> more contraction force —> increased ejection fraction
ejection fraction = stroke volume / end diastolic volume
SV in response to exercise…
