The Heart Flashcards
How many atria does the heart contain?
2 atria (left and right atrium)
Stage 1) Blood in right atrium: what happens?
The right atrium receives deoxygenated blood from the body (through the vena cava)
2) Deoxygenated blood in right ventricle: what happens?
Deoxygenated blood moves to right ventricle, which pumps it to the lungs via the pulmonary artery
3) Left atrium: what happens here?
Left atrium receives oxygenated blood from the lugs (through the pulmonary vein)
4) Left ventricle: what happens here?
The oxygenated blood move through to the left ventricle, which pumps it out round the whole body (via the aorta)
Why does the left ventricle have a thicker wall than the right ventricle?
It needs more muscle because it has to pump blood around the body at a high pressure, whereas the right ventricle only has to pump blood to the lungs.
What are the function of the valves?
To prevent the back flow of blood.
What is the cardiac output?
The volume of blood pushed into the aorta each minute.
What is the stroke volume?
The volume of blood pushed into the aorta in each beat (of the heart).
What is the equation for cardiac output?
Cardiac output = stroke volume x heart rate
litres/min) (litres/beat) x (beats/min
Equation for stroke volume?
Stroke volume = cardiac output / heart rate
Equation for heart rate?
Heart rate = cardiac output / stroke volume
What does regular exercise do to the heart?
Strengthens the heart muscles
Ventricle also increases
Why do fitter people have lower heart rates than unfit people?
- Fitter people - bigger stroke volume, heart can beat more slowly to achieve the same cardiac output as an UNFIT person
Why is the heart a ‘double pump’?
The blood passes through the right and then the left side of the heart before being pumped to the rest of the body.
