Cardiovascular System Flashcards
How does high blood pressure impact health?
Can cause damage to arteries and the heart which can cause an increase in the risk of heart attacks or strokes
How does regular exercise impact high blood pressure?
Blood pressure can be reduced by lowering systolic and diastolic pressure
What is an ischaemic stroke?
When a blood clot cuts off the blood supply to the brain
What is a haemmorhagic stroke?
A weakened blood vessel supplying the brain bursts
What are LDLs?
(Bad) - deliver bad fats to the cells
What are HDLs?
(Good) - take bad cholesterol to the liver to be broken down
How does exercise impact cholesterol?
Lowers LDLs and increases HDLs, increased HDLs help protect artery walls from LDLs
What is coronary heart disease?
When coronary arteries get blocked due to a build up of fatty deposits
What is atherosclorsis?
When atheromas (fatty deposits) block arteries
What is angina?
The pain and discomfort that occurs when pressure is put on the narrowed arteries as they cannot deliver enough oxygen to the heart
How can deposits cause heart attacks?
If a piece of deposit breaks off, a blood clot may form which causes a blockage, cutting off the supply of oxygenated blood to the heart
Does a trained or untrained person have a higher cardiac output?
Trained
Why does a trained athlete have a higher cardiac output than an untrained athlete?
A trained athlete has experienced cardiac hypertrophy, meaning their stroke volume and hence cardiac output has increased
What is sub-maximal exercise?
When an athlete works at a lower intensity and they do not reach their maximum heart rate
What is the impact of sub-maximal exercise?
Causes a significant increase in venous return due to vascular shunt mechanisms, this causes the chambers of the heart to become gradually stretch overtime, increasing diastolic fill
What is maximal exercise?
When an athlete works at high intensity and reach’s their maximum heart rate
What is the impact of maximal exercise?
Causes muscles to contract fully which press on nearby blood vessels, restricting blood flow - this causes an increase in blood pressure
Frequent training of this sort causes the cardiac muscles to become stronger as it must adapt to eject blood against higher levels of resistance
What is anticipatory rise?
When heart rate increases before exercise due to the release of adrenaline by the sympathetic nervous system
What is the vascular shunt mechanism controlled by?
Controlled by the Vasomotor Control Centre (VCC)
What is vascular shunt mechanism controlled by?
Vasoconstriction/dilation is controlled by the SNS
Pre-capillary sphincters control the movement of the blood vessels
What is the cardiac conduction system pathway?
SA node
Atrial systole
AV node
Bundle of his
Bundle branches
Purkinje fibres
Ventricular systole
What is the neural control mechanism controlled by?
The CCC (cardiac control centre)
What does the SNS do?
Stimulates the heart to beat faster
What does the PNS do?
Returns the heart to resting levels
What do the sympathetic nerves cause the release of once stimulated?
Adrenaline and noradrenaline
What do the hormones do?
Increase heart rate
Support the redistribution of blood
Stimulate breakdown of glycogen - provides fuel to the muscles
Stimulates the SA node - increases speed and force of contractions
Where is oxygen carried in the blood?
Haemoglobin (97%)
Plasma (3%)
How many oxygen molecules can haemoglobin carry?
4
What do chemoreceptors detect?
An increase in CO2
What is the process of chemoreceptor detection?
Detects
Relay info to the CCC
SNS is stimulated
What is the process of chemoreceptor detection?
Detects
Relay info to the CCC
SNS is stimulated
SA node is stimulated to increase heart rate
What do baroreceptors detect?
Stretch and pressure change in blood vessels
What is the process of baroreceptor deception?
Detection
Sends information to the CCC
Stimulates PNS
SA node decreases heart rate
What do propioreceptors detect?
Increase in muscle movement
What is the process of baroreceptor detection?
Detection
Sends information to the CCC
Stimulates SNS
SA node decreases heart rate
What is oxyhaemoglobin dissociation?
The release of oxygen from oxyhaemoglobin in the capillaries to the muscle tissues due to the lower pressure that exists there
What happens when oxygenated blood moves past the alveoli?
Oxygen diffuses from the high partial pressure in the capillaries to the lower partial pressure in the alveoli
Carbon dioxide diffuses from the high partial pressure in the alveoli to the lower partial pressure in the capillaries
What is oxygen stored by in the muscles?
Myoglobin
Why will myoglobin store oxygen?
For the mitochondria to use in aerobic respiration
What does the oxyhaemoglobin dissociation curve state about oxygen in the lungs?
Partial pressure in the lungs is high at rest in the lungs due to gas exchange being constantly undergone in the alveoli, meaning haemoglobin is always fully saturated
What does the oxyhaemoglobin dissociation curve state about partial pressure at the tissues?
Partial pressure is lower because there is less oxygen than in the lungs so haemoglobin is less saturated due to giving the oxygen away to the muscle tissues from the capillaries in order for it to diffuse across
What is Bohr Shift?
Changes in the oxyhaemoglobin dissociation curve as a result of carbon dioxide levels - results in the release of more oxygen in exercising muscles
What is the pulmonary system?
Deoxygenated blood from the heart to the lungs, oxygenated blood back to the heart from the lungs
What is the systemic system?
Oxygenated blood to the body from the heart, the return of deoxygenated blood from the body to the heart
What type of blood pressure do veins have?
Low
What type of blood pressure do arteries have?
High
What is blood pressure?
The force exerted by the blood against the blood vessel wall
What does systolic mean?
When blood is ejected - contraction
What does diastolic mean?
When blood fills the heart - relaxation
How does the skeletal muscle pump work?
The muscles surrounding the veins expand and contract, pressing on the veins and causing a pumping effect
The valves close when the muscles relax, preventing back flow
How does the respiratory pump work?
When muscles contract and relax during breathing in and out, pressure changes occur in the thoracic and abdominal cavities - these changes in pressure compress the nearby veins and assist blood return to the heart
How do valves work?
Valves ensure that blood only flows in one direction, once the blood has passed through them, they close
How does gravity assist venous return?
Helps return the blood from the upper body
How does smooth muscle assist venous return?
A thin layer in the walls of the veins that help squeeze the blood back to the heart
How does the suction pump assist venous return?
The action is aided by energy being stored in the muscle and providing power for suction that aids filling
What is venous return?
The volume of blood returning to the heart
What is ejection fraction?
The percentage of blood pumped out by the left ventricle per beat
What 3 factors does stroke volume depend on?
Venous return
Elasticity of the cardiac fibres
Greater contractions of the myocardium
What does Starling’s law say?
Increased venous return
Greater diastolic filling of the heart
Cardiac muscle stretched
More forceful contractions
Increased ejection fraction
What is cardiovascular drift?
An increase in heart rate despite no change in intensity
When and where does cardiovascular drift occur?
After at least 10 mins of steady exercise in a warm environment
Why does cardiovascular drift occur?
Due to a progressive decrease in stroke volume and arterial blood pressure
What is A-VO2 difference?
The difference in the oxygen content of the blood between the arterial and venous blood
