The Cardiovascular System Flashcards
Blood vessels of the heart
The vena cava brings deoxygenated blood back to the right atrium and the pulmonary vein delivers oxygenated blood to the left atrium.
The pulmonary artery leaves the right ventricle with the oxygenated blood to go to the lungs and the aorta leaves the left ventricle with oxygenated blood leading to the body.
Valves of the heart
Open to allow blood to pass through and then close to prevent backflow.
The tricuspid valve is located between the left atrium and right ventricle and the bicuspid valve between the left atrium and left ventricle is.
The semi lunar valves can be found between the right and left ventricles and the pulmonary artery and aorta.
Cardiac Conduction System
A group of specialised cells in the wall of the heart which sent electrical impulses to the cardiac muscle causing it to contract.
Myogenic impulse sent
sinoatrial node
atrioventricular node
Ventricular Systole begins
bundle of his
purkinje fibres
Contraction
sinoatrial node (SAN)
generates heartbeat
(pacemaker)
Atrioventricular node
Please impulse between the upper and lower sections of the heart
systole
heart contracts
bundle of his
transmit electrical impulses from the AVN via the bundle branches to the ventricles
pirkinje fibres
conduct impulses in the walls of the ventricles
sympathetic nervous system
stimulates the heart to beat faster
Impulses sent to the SAN and there is a decrease in parasympathetic nerve impulses so the heart rate increases
parasympathetic nervous system
Returns the heartbeat to resting level
What is the central nervous system made up of?
The brain and the spinal cord
What is the peripheral nervous system made up of?
Nerve cells that transmit information to and from the central nervous system (CNS)
Cardiac control centre
located in medulla oblongata in the brain.
co-ordinates CNS and PNS
stimulated by chemoreceptors, baroreceptors and proprioreceptors
Chemoreceptors
sense chemical changes (increase in CO2 during exercise). stimulates sympathetic nervous system to beat heart faster.
found in carotid arteries and aortic arch
Baroreceptors
Respond to the stretching of the arterial wall caused by changes in blood pressure.
send signals to the medulla oblongata
an increase in arterial pressure causes a decrease in HR
proprioceptors
located in muscles tendons and joints
provide information about movement and body position
send impulse to medulla
hormonal control mechanism
release of adrenaline stimulates SAN which increases speed and force of contraction and cardiac output
adrenaline
A stress hormone that is released by the sympathetic nerves and cardiac nerve during exercise which causes an increase in heart rate
Stroke volume
The volume of blood pumped out by the heart ventricles in each contraction (70ml increases 40-60% during exercise)
Diastole phase
When the heart relaxes to fill with blood
ejection fraction
The percentage of blood pumped out by the left ventricle per beat (60% but can increase to 85%)
Cardiac output
The volume of blood pumped out by the heart per minute
heart rate
the number of times the heart beats per minute (72)
220 - age = maximum HR
Maximal exercise
anticipatory rise.
Sharp rise in HR due to anaerobic work.
Stress of anaerobic systems.
sub-maximal exercise
Anticipatory rise.
Sharp rise due to anaerobic work. Steady state as athlete meets oxygen demand with oxygen supply
Cardiac hypertrophy
The thickening of the muscular wall of the heart so it becomes bigger and stronger
Bradycardia
A decrease in resting heart rate to below 60 BPM
Cardiac output in response to exercise
During exercise, there is a large increase in cardiac output due to an increase in heart rate and in stroke volume. Cardiac output will increase as the intensity of exercise increases until maximum intensity is reached and then it plateaus.
coronary heart disease
Coronary arteries become blocked or start to narrow by a gradual buildup of fatty deposits (atheroma) this process is called altheroclerosis.
Can be caused by high blood pressure, high levels of cholesterol, lack of exercise and smoking
the pain and discomfort is called angina
blood Pressure
The force exerted by the blood against the blood vessel wall
blood flow x resistance
high Blood pressure
Put extra strain on the arteries and heart and increases the risk of heart attack, heart failure, kidney disease, stroke or dementia
Low density lipoproteins
Bad.
Transport cholesterol in the blood to the tissues.
Linked to an increased risk of heart disease
High density lipoproteins
good
transport excess cholesterol in the blood back to the liver where it is broken down.
Lower the risk of developing heart disease
how does a stroke occur
blood supply to brain is cut off
steady state
Where the athlete is able to meet the oxygen demand with oxygen supply
cardiovascular shift
When heart rate and climbs during steady-state exercise
Progressive decrease in stroke volume and arterial blood pressure and a progressive rise and heart rate.
Occurs during prolonged exercise (after 10 minutes) in a warm environment
pulmonary circulation
Oxygenated blood from the heart to the lungs and oxygenated blood back to the heart.
systemic circulation
Oxygenated blood to the body from the heart and then the return of the oxygenated blood from the body to the heart.
blood pathway
heart
arteries
arterioles
capillaries
venules
veins
heart
veins
thinner muscle
low pressure of blood
wide lumen
valves
arteries
high pressure
small lumen
smooth.
elastic
inner layer
capillaries
one cell thick
slows down blood flow to allow time for diffusion.
short diffusion pathway
systolic blood pressure
high pressure in arteries when ventricles are contracting
an increase in systolic pressure increases venous return
diastolic pressure
lower pressure in arteries when ventricles are relaxing
venous return
The return of blood to the right side of the heart via the vena cava
increases during exercise
starlings law
Venus return increases and more blood is pumped out of the heart, stroke volume increases.
venous return mechanisms
skeletal muscle pump- muscular change in shape means that the muscles press on nearby veins and cause a pumping affect
respiratory pump- during breathing in and out, pressure changes compress nearby veins and assist blood return
pocket valves- insures blood only flows in One Direction
thin layer of muscle in vein walls
gravity
suction pump action of the heart.
oxygen during exercise %
3% dissolves into plasma
97% combines with haemoglobin to form oxyhaemoglobin
when fully saturated, haemoglobin carry for oxygen molecules. This occurs when the partial pressure of oxygen in the blood is high.
oxyhaemoglobin dissociation
The release of oxygen from oxyhaemoglobin to the tissues
myoglobin
Has a higher affinity for oxygen and will store the oxygen for the mitochondria until it is used by the muscles
oxyhaemoglobin dissociation curve
The partial pressure of oxygen in the lungs is high so haemoglobin is almost completely saturated with oxygen.
In the tissues, the partial pressure of oxygen is lower, therefore the haemoglobin gives up some of its oxygen to tissues.
bohr shift
When an increase in blood CO2 and a decrease in pH result in a reduction of the affinity of haemoglobin for oxygen.
Shifts to the right during exercise when muscles require more oxygen.
Factors responsible for the increase in the dissociation of oxygen from haemoglobin
Increase in blood temperature,
partial pressure of carbon dioxide increases,
pH
Vascular shunt mechanism
The redirecting of blood flow to the areas where is most needed
During exercise the skeletal muscles require more oxygen
vasodilation
The widening of blood vessels to increase the flow of blood into the capillaries
vasoconstriction
The narrowing of blood vessels to reduce blood flow into the capillaries
pre capillary sphincters
Tiny rings of muscle located at the opening of capillaries.
Aid blood redistribution
Why is the redistribution of blood important?
Increase the supply of oxygen to the working muscles.
Remove waste products from muscles.
Insure more oxygen goes to skin to regulate body temperature.
Direct more blood to heart.
atrio-venous difference
The difference between the oxygen content of the arterial blood arriving at the muscles and the Venus blood leaving muscles.
