1.1b Cardiovascular system Flashcards
what does the cardiovascular system refer to?
heart
blood
blood vessels
What is the pulmonary circuit?
Circulation of blood through the pulmonary arteries to lungs and pulmonary veins back to the heart.
What is the systemic circuit?
Circulation of blood through the aorta to the body and vena cavae back to the heart.
What is the pathway of oxygenated blood once it leaves the lungs?
pulmonary vein left atrium bicuspid/mitral valve left ventricle semilunar valve aorta body
What is the pathway of deoxygenated blood once it after it leaves the rest of the body?
vena cava right atrium tricuspid valve right ventricle semilunar valve pulmonary artery lungs
Describe the left side of the cardiac muscle compared to right and explain why.
left side has a thicker muscular wall
allows it to forcefully contract to circulate oxygenated blood through the systemic system to muscles and organs
How many chambers does the heart have and what are they?
4 right atrium left atrium right ventricle left ventricle
How many valves does the heart have and what are they?
4 tricuspid valve bicuspid valve pulmonary semilunar valve aortic semilunar valve
How many blood vessels attach to the heart and what are they?
4 vena cava pulmonary artery pulmonary vein aorta
How many features of the conduction system are there and what are they?
4 SA node AV node bundles of His Purkinje fibre
What is the conduction system?
A specialist bundle of tissues that transmit the electrical pulse through the heart causing a coordinated contraction.
Where is the SA node and what does it do?
wall of right atrium
sends an impulse across both atria causing atrial systole
Where is the AV node and what does it do?
In the middle wall of the heart between atria and ventricles.
Receives impulse from SA node, delays it for a moment to allow for atrial systole to finish and sends it down the bundles of His.
Where is the bundles of His and what does it do?
In middle wall of the heart.
Transmit impulse to the bottom of the right and left side of the heart.
Where is the Purkinje fibres and what does it do?
In walls of ventricles.
Cause impulse to penetrate into ventricle wall causing ventricular systole.
Define the cardiac cycle.
All the events associated with the flow of blood through the heart during one complete heartbeat.
- atrial diastole
- atrial systole
- ventricular diastole
- ventricular systole
What controls the cardiac cycle?
Conduction system –> to produce highly coordinated contractions of the heart
Define systole.
It is the heart working
The contraction phase of the heart chamber when it is pumping blood out.
1. atrial systole - blood pumped into ventricles
2. ventricular systole - blood pumped into pulmonary artery and aorta
Define diastole.
It is the heart relaxing
The relaxation phase of the heart chamber when it is receiving blood.
1. atrial diastole - blood entering the atria via vena cava and pulmonary vein
2. ventricular diastole - blood entering the ventricles from the atria
What are the events that happen in one heart beat during atrial diastole?
No electrical impulse
Atria fill with blood from vena cava and pulmonary vein
AV valves closed.
Atrial pressure rises above ventricular pressure
Blood starts to pass passively into ventricles
What are the events that happen in one heart beat during atrial systole?
SA node fires electrical impulse across atria.
Atria contract.
AV valves forced open
Remaining blood is pumped into ventricles
Semilunar valves close
What are the events that happen in one heart beat during ventricular diastole?
Impulse received by AV node
Delay impulse for a moment to allow atria systole to complete
AV valves close
AV node sends impulse down right and left bundles of His into the Purkinje fibres
What are the events that happen in one heart beat during ventricular systole?
Ventricles contract from the bottom upwards.
Semilunar valves forced open
Blood is pumped out of ventricles into pulmonary artery and aorta
Define heart rate. (HR)
The number of times the heart beats per minute.
units = bpm
What is the average heart rate at rest?
70 bpm
What is the heart rate for endurance athlete?
50 bpm
How can you calculate maximum HR?
200bpm - age
What is it called when the resting HR is less that 60bpm?
bradycardia
caused by increased size and strength of heart known as cardiac hypertrophy
How is cardiac output calculated?
cardiac output = stroke volume x heart rate
Q = SV x HR
Define stroke volume. (SV)
The amount of blood ejected from the left ventricle per beat
units = ml
What is the average stroke volume at rest?
70ml
What is the stroke volume for endurance athlete?
100ml
What is Frank-Starling’s law of the heart?
SV depends on venous return (VR)
VR is the volume of blood returning to the heart
If VR increases SV increases and therefore force of contraction
Define cardiac output (Q)
the amount of blood ejected from the left ventricle per minute
unit = l/min
What is the average cardiac output at rest?
5 l/min
What is the cardiac output for endurance athlete?
5 l/min
Why does an endurance athlete have bradycardia?
Their heart is so efficient due to hypertrophy that it pumps more blood per minute so their resting heart rate is below 60bpm.
What is sub-maximal?
a low to moderate intensity pf exercise within a performer’s aerobic capacity
What is venous return?
the return of blood to the right atria through the veins
What is maximal?
a high intensity of exercise above a performer’s aerobic capacity that will induce fatigue
What is the CCC?
Cardiac control centre
a control centre in the medulla oblongata responsible for HR regulation
When is the CCC used?
When a situation arises needing the increase or decrease in hear rate
What is the sympathetic nervous system?
part of the autonomic nervous system responsible for increasing HR specifically during exercise
What is the parasympathetic nervous system?
part of the autonomic nervous system responsible for decreasing HR specifically during recovery
What is the ANS and what does it do?
autonomic nervous system
determines the firing of the SA node
What are the 3 factors which control he activity of the CCC?
Neural control
intrinsic control
hormonal control
What is neural control?
proprioceptors –>in muscles and joints, tell CCC that movement has increased
chemoreceptors –>in aorta and carotid arteries, detect decrease in blood pH due to an increase in lactic acid
baroreceptors–>in blood vessel walls, inform CCC of increase in blood pressure
What is intrinsic control?
temperature–>changes affect blood viscosity and speed of nerve impulse transmission
venous return–>changes will affect stretch in ventricle walls, force of contraction and therefore SV
What is hormonal control?
adrenaline and noradrenaline–> these are released from the adrenal glands and increase SV and HR
What is vasodilation?
widening of arteries, arterioles and pre-capillary sphincters
What makes up the vascular system?
blood vessels
blood - 45% cells + 55% plasma
Name the types of blood vessels.
arteries + arterioles
capillaries
veins + venues
What are the features of arteries/arterioles?
Contain blood under high pressure
Have a large layer of smooth muscles and elastic tissue to vasodilator and vasoconstrict
Arterioles have a ring of smooth muscle surrounding the capillary bed to control blood flow through dilation and constriction
What are the features of capillaries?
Capillary walls are one cell thick
Is where gas exchange takes place
What are the features of veins/venules?
Carry deoxygenated blood
Have thin walls
Small layer of smooth muscle to allow ventilate and venoconstrict
Contain blood under low pressure
Have one-way pocket valves to prevent blood flowing backwards against gravity
What is vasodilation?
Widening of arteries, arterioles and pre-capilary sphincters
What is vasoconstriction?
narrowing of arteries, arterioles and pre-capilary sphincters
What is deoxygenated blood?
Blood depleted of oxygen and saturated with carbon dioxide and waste products
What is venodilation?
widening of the veins and venules
What is venoconstricton?
Narrowing of veins and venules
