The Cardiovascular System Flashcards
(23 cards)
What is the cardiac conduction system and what happens within it?
Sinoatrial node - the heart’s natural pacemaker. sends electrical signals to initiate heartbeat. located in right atrium.
Atrioventricular node - delays electrical signals. atria contracts and ventricles fill with blood.
Bundle of His - left and right pathways the electrical signals go down.
Purkinje Fibres - sends electrical signals so the ventricles contract more forcefully, so blood is pumped around the body.
Explain how ATP keeps us moving.
ATP is used and phosphate is lost.
ADP is produced.
Phosphocreatine turns ADP to ATP fastest.
When phosphocreatine is no longer present the body uses oxygen to break down fats and carbohydrates.
However, when there is a lack of oxygen (anaerobic), the byproduct lactate is produced.
What does the cardiovascular system include and what side is pulmonary and systemic circulation?
It includes the heart, aterioles, venuoles, veins, arteries and capillaries.
The pulmonary circulation is on the right side and has deoxygenated blood, whereas the systemic circulation is on the left side, and has oxygenated blood.
What are the three types of blood vessel and their structure?
Arteries take blood away from the heart. They have thicker and more muscular walls and a thinner lumen than veins.
Veins take blood to the heart. They have thin walls, have valves and a wider lumen than arteries. Valves prevent the backflow of blood.
Capillaries allow oxygen and carbon dioxide to pass through..They have one cell thick walls, are the smallest blood vessel.
What is systole and diastole?
Systole is when the heart contracts and pumps blood around the body.
Diastole is when the heart relaxes and fills with blood.
What is anticipatory rise, adrenaline and acetylcholine?
Anticipatory rise is the increase in heart rate before exercise.
Adrenaline increases heart rate increases heart rate during exercise.
Acetylcholine decreases heart rate.
What are the three types of receptors and what do they detect?
Chemoreceptors detect changes in carbon dioxide.
Baroreceptors detect changes in blood pressure. Increase in blood pressure = decrease in heart rate.
Proprioreceptors detect changes in movement. Located in muscles and tendons.
Explain how heart rate is regulated during exercise.
The Parasympathetic Nervous System (PNS) slows down heart rate. The vagus nerve sends signals so acetylcholine gets released and binds to receptors on the sinoatrial node. This lowers the rate of electrical impulses, slowing down heart rate.
The Sympathetic Nervous System (SNS) speeds up heart rate. Nerve signals from the medulla travel out to the spinal cord and branch it through cardiac accelerator nerves. Nerves release norepinephrine and epinephrine. Those neurotransmitters bind to receptors on SA node, increasing the rate of electrical impulses, speeding up heart rate.
What is Starling’s Law?
Describes the relationship between venous return and stroke volume.
If venous return increases, stroke volume increases If venous return decreases, stroke volume decreases.
The amount of blood that leaves the heart must be equal to the blood that travels back to the heart.
What is venous return and what are the venous return mechanisms?
Venous return is the movement of blood back to the heart.
The venous return mechanisms are:
- Pocket valves
- Skeletal muscle pump - the skeletal muscle contracts, squashing the vein, forcing blood towards the heart
- Respiratory pump
- Gravity
What is the effect of exercise on blood pressure?
Short term - increase in blood pressure.
Long term - decrease in blood pressure at rest.
What is vascular shunt, and where does vasoconstriction and vasodilation happen during exercise?
Vascular shunt is the redistribution of blood - towards the working muscles from the digestive system.
There is vasoconstriction of capillaries at the digestive system.
There is vasodilation of capillaries at the working muscles.
What is a-VO2 difference and cardiovascular drift?
a-VO2 difference is the difference in oxygen content in arteries and veins.
Cardiovascular drift is the constant increase of heart rate during steady state exercise due to dehydration and increased temperature.
What are adaptations of training for the cardiovascular system?
Cardiac hypertrophy -> leads to increased stroke volume.
Increased capillarisation -> leads to increased levels of oxygen that get to the muscles.
Increased mitochondrial density.
Greater a-VO2 difference.
More blood -> leads to haemoglobin levels increasing.
What is the Bohr shift?
The Bohr shift is where certain conditions make haemoglobin less likely to keep binding to oxygen, causing it to release the oxygen more easily to the tissue.
The conditions that can cause it are an increase in:
- Temperature
- Acidity/CO2
- Blood pressure
How is oxygen transported?
3% dissolves in plasma.
97% combines with haemoglobin.
How is carbon dioxide transported?
70% - transported the blood as carbonic acid.
23% - combines with haemoglobin to form carbaminohaemoglobin.
7% - dissolved in plasma.
What is atherosclerosis, atheroma and angina?
Atherosclerosis is the process of fatty deposits building up in the arteries.
Atheroma is the build up of fatty deposits in the arteries.
Angina is chest pain that is caused by reduced blood flow to the heart muscles.
What happens when someone has high blood pressure and how does exercise help?
Fat builds up and narrows the lumen, so blood pressure increases.
Exercise prevents blood vessels from narrowing, helps deliver blood to the heart and helps to maintain a normal heartbeat.
How much physical activity is recommended?
Adults (19 to 64) - 150 minutes of moderate intensity activity, or 75 minutes of vigorous activity.
What is LDL and what is HDL?
LDL (Low density lipoproteins) - are bad, they are linked to an increase in heart disease.
HDL (High density lipoproteins) - transports extra cholesterol to the liver where it’s broken down. are good, they lower the risk of developing heart disease,. protects artery walls against LDL/an anti-inflammatory response.
What are the physical, social and psychological benefits of exercise?
Physical - fit for everyday tasks, reduces the risk of a stroke, helps prevent certain types of cancer.
Social - make friends, gives you emotional support.
Psychological - helps to treat anxiety and depression, improves confidence and self-esteem, releases dopamine.
What is a stroke, and what are the two types?
A stroke is the lack of oxygen to the brain due to a blockage.
Ischemic - most common, a blood clot stops blood supply to part of the brain.
Hemorrhagic - bleeding in or around the brain.
