Cardiovascular system Flashcards
What is meant by myogenic?
This means your heart can function independently without external stimulation.
What is systole?
When an area of your heart is contracting.
What is diastole?
When an area of your heart is relaxing.
What does the cardiac muscle do?
It constantly contracts to make your heart beat, to pump blood around your body.
In order to do this it needs to be constantly supplied with oxygen from the blood vessels.
What are the chambers of the heart?
• Atria
• Ventricles
What do the atria do? include wall thickness.
They have thin walls and receive blood coming from the rest of the body to the heart.
They contract simultaneously.
What do the ventricles do? include wall thickness.
They have thick walls and forcefully pump blood to the lungs and the rest of the body.
They contract a short time after the atria.
What are the 3 main blood vessels?
• Arteries
• Veins
• Capillaries
What are the key features of the arteries?
• Thick and muscular walls to withstand the flow of blood at a high pressure as it leaves the heart.
• Small lumen
What are the key features of the veins?
• Thin walls
• Large lumen
• Contain valves to prevent back flow
What are the key features of the capillaries?
• One cell thick
• Small lumen so blood can pass through one cell at a time
• Walls have a semi-permeable membrane to allow the transport of gases and nutrients into and out of the blood. This also helps to provide energy for contraction.
What do the arteries do?
They carry oxygenated blood away from the heart. Unless it is the pulmonary artery, as this carry’s deoxygenated blood from the heart to the lungs.
What do the veins do?
They carry deoxygenated blood towards the heart. Unless it is the pulmonary vein, as this carry’s oxygenated blood from the lungs to the heart.
What do the capillaries do?
They allow the diffusion of gases (O2) and nutrients from the blood.
What is the heart protected by?
• Sternum
• Ribs
• Enclosed in the pericardium
How do you identify the sides of the heart on a diagram?
The left side of the heart has thicker muscle.
What does the right side of the heart do?
The right side of the heart receives deoxygenated blood from the vena cava and pumps it to the lungs via the pulmonary artery.
What does the left side of the heart do?
The left side of the heart receive oxygenated blood from the pulmonary veins and pumps it to the whole body via the aorta.
What pathway does deoxygenated blood take through the body?
Inferior vena cava
|
Right atrium
|
Tricuspid valve
|
Right ventricle
|
Pulmonary valve
|
Pulmonary artery
|
Lungs
What pathway does oxygenated blood take through the body?
Lungs
|
Pulmonary vein
|
Left atrium
|
Bicuspid valve
|
Left ventricle
|
Aortic valve
|
Aorta
What is the cardiac cycle?
• Atrial diastole - The atria fill with blood from the vena cava and pulmonary veins.
• The SA (sinoatrial node) of the right atrium lets out an impulse, that spreads through the atria walls causing them to contract in unison.
• The blood is then forced into the ventricles.
• The impulse is received by the AV (atrioventricular node) and the signal is then delayed by 0.1 second. This is to ensure the atria are empty before the ventricles contract.
• The signal is then conducted through the Bundle of His, to the purkinje fibres.
• The purkinje tissue then conducts the signal through the ventricle walls, causing them to contract from the apex up.
• The pressure increase in each ventricle forces the semi lunar valves to open.
• The heart chambers then relax to prepare for the next cycle.
What is cardiac output?
The volume of blood pumped by the left side of the heart per minute.
This can be used to calculate heart efficiency.
How do you calculate cardiac output and what is it measured in?
It is measured in ml/min (ml per min).
Cardiac
output = BPM x Stroke Volume
What is stroke volume and what is it measured in?
The volume of blood pumped per beat.
It is measured in ml.
