cardiovascular system Flashcards
what does the cardiovascular system include
blood vessels and the heart
what does the heart do during exercise
works to pump blood through the various blood vessels to deliver oxygen and nutrients to the working muscles and gather waste products such as carbon dioxide
what is the heart described as being
myogenic
what does myogenic mean
originating in the muscle tissue
where does the electrical impulse in the heart start
the sinoatrial node
explain what happens in the sinoatrial node
the electrical impulse starts here then spreads throughout the heart which is described as a wave of excitation
what does the impulse do from the sinoatrial node
spreads through the walls of the atria causing them to contract
atrial systole
what is it called when the atria contract
atrial systole
after the sinoatrial node where does the impulse go next
passes through the atrioventricular node where the impulse is delayed approximately 0.1 seconds to enable the atria to fully contract before ventricular systole begins
what does the atrioventricular node do
delays the electrical impulse for approximately 0.1 seconds to allow the atria to fully contract before ventricular systole begins
after the atrioventricular node, where does the electrical impulse go
travels down the bundle of his which branches into two bundle branches
after the bundle of his where does the electrical impulse go
the purkinje fibres which spread spread throughout the ventricles causing them to contract (ventricular systole)
what do the purkinje fibres do
they spread throughout the ventricles, causing the ventricles to contract which is called ventricular systole
what is the sinoatrial node also known as
the pacemaker of the heart
give the order in which the cardiac impulse travels in
sinoatrial node
atrioventricular node
bundle of his
purkinje fibres
what does the conduction system do during exercise
ensure that the heart rate increases to allow the working muscles to receive more oxygen
what does the sympathetic nervous system do
stimulates the heart to beat faster
what does the parasympathetic nervous system do
returns the heart rate to its resting level
what are the parasympathetic and sympathetic nervous system co-ordinated by
the cardiac control centre
where is the cardiac control centre located
in the medulla oblongata
what is the cardiac control centre stimulated by
chemoreceptors, baroreceptors and proprioceptors
what will a signal sent to the sympathetic system do
increase the heart rate
what will as signal sent to the parasympathetic system do
decrease the heart rate
explain what chemoreceptors do
detect an increase in blood carbon dioxide
a signal goes to the cardiac control centre
then onto the sympathetic system
to the sinoatrial node which increases the heart rate
explain what baroreceptors do
detect an increase in blood pressure
send a signal to the cardiac control centre
which sends a signal to the parasympathetic nervous system
which sends a signal to the sinoatrial node to decrease the heart rate
explain what proprioceptors do
detect an increase in muscle movement
this sends an impulse to the cardiac control centre which sends information to the sympathetic system to the sinoatrial node to increase the heart rate
what do chemoreceptors detect and what happens to the heart rate
increase in blood carbon dioxide
heart rate will increase
what do baroreceptors detect and what happens to the heart rate
increase in blood pressure
decreases heart rate
what do proprioceptors detect and what happens to the heart rate
increase in muscle movement
increases the heart rate
what type of hormone is adrenaline
a stress hormone
what releases adrenaline
the sympathetic nerves and cardiac nerve
what does adrenaline stimulate
the sinoatrial node
what does adrenaline do
increases the speed and force of a contraction increasing the cardiac output causing the volume of blood pumped to the working muscles increase
what is the hormone released that’s the opposite to adrenaline
acetylcholine
what is acetylcholine released by
the parasympathetic nervous system
what does acetylcholine do
slows down the heart rate
what is stroke volume
the volume of blood pumped out by the hearts ventricles in each contraction
what is the average resting stroke volume
70ml
what does stroke volume depend on
venous return
elasticity of cardiac fibres
contractility of cardiac tissue
what is venous return
the return of blood to the right side of the heart via the vena cava
what is ejection fraction
the percentage of blood pumped out by the left ventricle per beat
why does the elasticity of cardiac fibres increase stroke volume
the more the cardiac muscles can stretch the greater the force of contraction a greater force of contraction increases the ejection fraction
what is the elasticity of the cardiac fibres concerned with
the degree of stretch of the cardiac tissues during the diastole phase
what is the diastole phase
when the heart is relaxed
how does the contractility of the cardiac tissue effect stroke volume
the greater contractility of cardiac tissue the greater the force of contraction this results in an increase in stroke volume as well as ejection fraction
what happens to stroke volume when exercise intensity increases
stroke volume also increases
when is this only the case for
40-60% of maximum effort
what happens after 40-60% of maximum effort to stroke volume
stroke volume plateaus because the ventricles do not have as much time to fill up with blood so can not pump out as much blood
what is heart rate
the number of times the heart beats per minute
what is the average resting heart rate
72 beats per minute
what does heart rate do with exercise
it increases
how do you find the maximum heart rate
220-age
when does cardiac hypertrophy occur
regular aerobic training
what is an anticipatory rise
hormonal action of adrenaline which causes the SAN to increase in heart rate
why does the brain need a constant supply of oxygenated blood and nutrients
to maintain its function
what is cardiac hypertrophy
when the heart becomes bigger and stronger due to the thickening of the muscle wall
what does CHD stand for
coronary heart disease
what is bradycardia
when there is a decrease in resting heart rate to below 60bpm
what is similar about everyone’s cardiac output at rest
it is the same
what happens when bradycardia occurs
oxygen delivery to the muscles improves as there is less oxygen needed for contraction of the heart
tell me about HDL
high density lipoproteins transport excess cholesterol in the blood back to the liver where it is broken down these are classed as ‘good’ cholesterol since they lower the risk of developing heart disease
tell me about LDL
low density lipoproteins transport cholesterol in the blood to the tissues and are classed as ‘bad’ cholesterol since the are linked to increased risk f heart disease
what is cardiac output
the volume of blood pumped out the heart by the ventricles per minute
what is the cardiac output equation
cardiac output= stroke volume x heart rate
when does coronary heart disease occur
when your coronary arteries which supply the heart muscle with oxygenated blood becomes blocked or starts to narrow by gradual build up of fatty deposits
what happens to cardiac output during exercise
it increases
in relation to strokes what can regular exercise help to do
can help lower your blood pressure and help you to maintain a healthy weight which can reduce your chance of stroke by 27%
why does cardiac output increase during exercises
because heart rate and stroke volume also increase
what are fatty deposits called
atheroma
what is atherosclerosis
when arteries harden and narrow and become clogged up by fatty deposits
what does the brain need a constant supply of
oxygenated blood and nutrients
where does the pressure from blood come from when it is exerted on a blood vessel wall
from the heart as it pumps blood around the body
what can cause atherosclerosis
high blood pressure, high levels of cholesterol, lack of exercise as well as smoking
what can regular aerobic exercise do when having a high blood pressure
reduces the risk of heart attack by 20% because it lowers both systolic and diastolic pressures by 5-10mmHg
what happens if high blood pressure is left untreated
increases the risk of heart attack, heart failure, kidney disease, stroke or dementia
what is high blood pressure
blood pressure is the force exerted by the blood against a blood vessel wall
what can reduce blood pressure
regular aerobic exercise can reduce blood pressure
how many types of cholesterol are there
2 types
what does high blood pressure put strain on
the arteries and heart
what are the two types
low density lipoproteins
high density lipoproteins
what can regular physical activity do to the two types of cholesterol
it lowers bad LDL cholesterol levels and at the same time it significantly increases good HDL cholesterol levels
what are the two main types of stroke
ischaemic and haemorrhagic
tell me about an ischaemic stroke
they are the most common form and occur when a blood clot stops the blood supply
what can blood supply that is cut off from the brain lead to
brain injury, disability, and sometimes death
when does cardiovascular drift occur
it occurs during prolonged exercise in a warm environment despite the exercise intensity staying the same
tell me about a haemorrhagic stroke
occur when a weakened blood vessel supplying the brain bursts
when does a stroke occur
when the blood supply to part of the brain is cut off causing damage to brain cells so they start to die
what is the most common type of stroke
ischaemic
what is cardiovascular drift characterised as
the progressive decrease in stroke volume and arterial blood pressure together with a progressive rise in heart rate
what happens during cardiovascular drift to plasma volume
plasma volume decreases due to the increased sweating response of the body and this reduces venous return and stroke volume. heart rate then increases to compensate and maintain cardiac output
