TrES2b
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just want someone to make sure i have this in the correct sequence

The inferior vena cava collects deoxygenated blood from the lower parts of the body. The superior vena cava collects deoxygenated blood from the upper parts of the body. The deoxygenated blood is delivered to the right atrium under low pressure.
The right atrium then receives the low pressure deoxygenated blood from both of the great veins. It then fills up with blood which causes the pressure to build up which forces the tricuspid valve to open allowing the right ventricle to fill up with blood. When the right atrium is full it contracts forcing more blood into the ventricle.
The tricuspid valve closes to prevent backflow into the atrium. The right ventricle contracts once the atrium has contracted this forces the semilunar valve to open and blood is pumped out of the heart into the pulmonary artery. The pulmonary artery takes the deoxygenated blood into the capillaries in the lungs.
The right atrium relaxes and the semilunar valves close.The pulmonary vein brings oxygenated blood from the lungs into the heart. The oxygenated blood enters the left atrium. The left atrium contracts to pump blood into the left ventricle which forces the bicuspid valve to open. The blood is at high pressure which forces the bicuspid valve to close. Once the left ventricle has filled with blood it contracts forcing the semilunar valve to open. This allows the blood to enter the aorta which takes blood of very high pressure to the whole body. The semilunar valve then closes. During the cardiac cycle, the blood flows through both sides of the heart at the same time.

Both atria contract at the same time and both ventricles contract at the same time.
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CJField
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1. around 80% of blood naturally flows from the right atrium into the right ventricle, and the remaining 20% is pushed out via atrial systole.
2. There is a small gap between atrial systole and ventricular systole to allow blood to flow in. This is achieved by holding the impulse in the atrioventricular node. (not sure if you need to know that but it is good to know)
3.There are 4 pulmonary veins
4. better words for relax and contract and diastole and systole respectively

However overall this is perfect. My comments are just extra bits you don't really need
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TrES2b
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(Original post by CJField)
1. around 80% of blood naturally flows from the right atrium into the right ventricle, and the remaining 20% is pushed out via atrial systole.
2. There is a small gap between atrial systole and ventricular systole to allow blood to flow in. This is achieved by holding the impulse in the atrioventricular node. (not sure if you need to know that but it is good to know)
3.There are 4 pulmonary veins
4. better words for relax and contract and diastole and systole respectively

However overall this is perfect. My comments are just extra bits you don't really need
no i appreciate it so much thank you for this
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Jpw1097
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(Original post by TrES2b)
just want someone to make sure i have this in the correct sequence

The inferior vena cava collects deoxygenated blood from the lower parts of the body. The superior vena cava collects deoxygenated blood from the upper parts of the body. The deoxygenated blood is delivered to the right atrium under low pressure.
The right atrium then receives the low pressure deoxygenated blood from both of the great veins. It then fills up with blood which causes the pressure to build up which forces the tricuspid valve to open allowing the right ventricle to fill up with blood. When the right atrium is full it contracts forcing more blood into the ventricle.
The tricuspid valve closes to prevent backflow into the atrium. The right ventricle contracts once the atrium has contracted this forces the semilunar valve to open and blood is pumped out of the heart into the pulmonary artery. The pulmonary artery takes the deoxygenated blood into the capillaries in the lungs.
The right atrium relaxes and the semilunar valves close.The pulmonary vein brings oxygenated blood from the lungs into the heart. The oxygenated blood enters the left atrium. The left atrium contracts to pump blood into the left ventricle which forces the bicuspid valve to open. The blood is at high pressure which forces the bicuspid valve to close. Once the left ventricle has filled with blood it contracts forcing the semilunar valve to open. This allows the blood to enter the aorta which takes blood of very high pressure to the whole body. The semilunar valve then closes. During the cardiac cycle, the blood flows through both sides of the heart at the same time.

Both atria contract at the same time and both ventricles contract at the same time.
Yes, most of what you have said is correct, but there are a few inaccuracies.

(Original post by TrES2b)
When the right atrium is full it contracts forcing more blood into the ventricle
The right atrium does not need to be full before it contracts, in fact, atrial contraction contributes very little to the volume of blood in the ventricles, most ventricular filling is passive.

(Original post by TrES2b)
The tricuspid valve closes to prevent backflow into the atrium. The right ventricle contracts once the atrium has contracted this forces the semilunar valve to open and blood is pumped out of the heart into the pulmonary artery.
It sounds like you’re saying that the tricuspid valve closes before the right ventricle contracts. This is not the case, the tricuspid valve closes when the right ventricle contracts because the ventricular pressure is greater than the atrial pressure. All blood flow and valve opening/closing is due to pressure differences in the heart.

Otherwise not bad.
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TrES2b
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(Original post by Jpw1097)
Yes, most of what you have said is correct, but there are a few inaccuracies.



The right atrium does not need to be full before it contracts, in fact, atrial contraction contributes very little to the volume of blood in the ventricles, most ventricular filling is passive.



It sounds like you’re saying that the tricuspid valve closes before the right ventricle contracts. This is not the case, the tricuspid valve closes when the right ventricle contracts because the ventricular pressure is greater than the atrial pressure. All blood flow and valve opening/closing is due to pressure differences in the heart.

Otherwise not bad.
thank you so much!! would you say this is more accurate:

Deoxygenated blood enters the right atrium via the vena cava under low pressure. Whilst this is happening oxygenated blood enters the left atrium via the pulmonary vein. This is diastole.

The deoxygenated blood is delivered to the right atrium under low pressure. The right atrium then receives the low pressure deoxygenated blood from both of the great veins. It then fills up with blood The right atrium then contracts forcing the tricuspid valve to open and the right ventricle fills up with blood. The left atrium also contracts at the same time and the pressure forces the bicuspid valve to open and the left ventricle begins to fill up with oxygenated blood

The right ventricle then contracts and the difference in pressure forces the tricuspid valve to close to prevent the backflow of blood. the difference in pressure is due to the ventricular pressure being higher than the atrial pressure. The blood pushes open the semilunar valves and The blood is then taken to the lungs via the pulmonary artery. While this happens at the same time, the left ventricle contracts and the pressure forces the bicuspid valve to close to prevent the backflow of blood. the blood pushes open the semilunar valves open and moves into the aorta to deliver high-pressure blood to the whole body.

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