The heart Flashcards
What type of blood does the right side of the heart pump?
Deoxygenated
Where does the right side of the heart pump blood to?
Lungs
Where does the left side of the body pump oxygenated blood to?
The whole body
Which ventricle of the heart has thicker and more muscular walls? Why?
Left
To help pump the blood around the whole body whereas the right ventricle only has to pump it to the lungs
Do the ventricles or the atria have thicker walls? Why?
The ventricles have to push the blood out of the heart whereas the atria just have to pump it within the heart
What type of blood does the left side of the heart pump?
Oxygenated
What is the purpose of valves?
To maintain a pressure gradient
To prevent the back flow of blood
What are the two valves?
Semilunar valves
Atrioventricular valves
What is the purpose of the semilunar valves?
Link the ventricles and the pulmonary artery and the aorta
Stop blood flowing back into the heart once the ventricles have contracted
What is the purpose of the atrioventricular valves?
Link the atria to the ventricles and stop the blood flowing back into the atria when the ventricles contract
What is the purpose of cords?
Attach the atrioventricular valves to the ventricles to stop them being forced up into the atria when the ventricles contract
What is systole?
Cardiac contraction
What is diastole?
Cardiac relaxation
What is the first stage of the cardiac cycle?
- Ventricles relax (diastole)
- Atria contract (systole), decreasing the volume of the chambers and increasing the pressure to push blood into the ventricles
What is the second stage of the cardiac cycle?
- Atria relax (diastole)
- Ventricles contract (systole) which increases their pressure
- Pressure becomes higher in the ventricles than the atria, forcing the AV valves shut
- Pressure in the ventricles is also higher than in the aorta and pulmonary artery which opens the SL valves so blood flows out of the arteries
What is the third stage of the cardiac cycle?
- Both ventricles and atria relax
- Higher pressure in the arteries cause the SL to close
- Heart starts to fill again with blood
- Pressure in atria increases
- The pressure falls in the ventricles below that of the atria so the AV valves open and blood flows into the ventricles from the atria and the process repeats
What are the three summarised stages of the cardiac cycle?
- Ventricles relax, atria contract
- Ventricles contract, atria relax
- Ventricles relax, atria relax
What is the equation for calculating cardiac output?
Cardiac output = stroke volume x heart rate
What is cardiac output?
Volume of blood pumped by the heart per minute
What is heart rate?
The number of beats per minute
What is stroke volume?
The volume of blood pumped during each heartbeat
What equation do you use to calculate stroke volume?
Stroke volume = cardiac output / heart rate
What equation do you use to calculate heart rate?
Heart rate = Cardiac output / stroke volume
What are the units for cardiac output?
cm3 min-1
What are the units for stroke volume?
cm3
What are the units for heart rate?
bpm
