The heart is one of the most vital organs of our body. It is part of our body’s circulatory system. The job of the heart is to circulate the supply of blood, oxygen, hormones, and nutrients to all parts of the body with the help of blood vessels. To do this, the heart needs to pump out the blood at high pressure.
There are two types of pressures of the heart – systolic pressure and diastolic pressure. They vary in the various chambers of the heart.
The Diastolic Phase of the Heart
The diastolic phase of the heart is part of the cardiac cycle. It is the time when the closure of the semilunar falls, and the subsequent closure of the atrioventricular walls are silent because the flow through the large valve orifices is slow.
In simple terms, it is the phase of the heart in which low blood pressure is experienced and the heart is relaxed.
The diastolic phase of the heart is when the blood flows into the heart. It is followed by the systolic phase, in which the blood flows away from the heart towards the other parts of the body. The diastolic phase of the heart is characterised by ventricular relaxation, as during the diastolic phase, the two ventricles of the heart are relaxing from the contraction.
The Performance of the Heart During the Diastolic Phase
The muscles of the heart are in a relaxation state during the diastolic phase. It can also be regarded as the pause between the heartbeats. After the heart pumps out the blood from the ventricles to the atrium and then to the other parts of the body with high pressure, the diastolic phase follows.
In the diastolic phase, the heart relaxes, and the atrioventricular valves facilitate the flow of blood from the parts of the body to the atrium and then to the ventricles.
Types of Diastolic Phases
The following are the two types of the diastolic phases:
- Ventricular Diastole
During this period, both the atria of the heart and the ventricles are relaxed, and the atrioventricular valves open up.
The blood from which the oxygen has been absorbed by the body parts is returned to the heart into the right atrium. Before that, the blood passes through the superior and inferior vena cava.
During this phase, the right atrium empties the blood from it into the right ventricle. The tricuspid valve makes sure that the blood does not flow back into the right atrium.
- Atrial Diastole
During the atrial type of the diastolic phase, the atrioventricular valves open up, and the semilunar valves are closed.
The blood containing oxygen from the superior and the inferior vena cava fills up the right atrium. The left ventricles receive all the content from the left atrium, and the content of the right atrium is emptied to the right ventricle.
The valve situated between the left ventricular and left atrium is called the mitral valve, which avoids the flow of blood from ventricles right back to the atrium.
The Diastolic Pressure
The pause between the two heartbeats is regarded as the diastolic phase. Hence, the muscles of the heart are relaxed during this phase.
For pumping out the blood from the heart to other parts of the body, a lot of pressure is required. However, for the blood to travel from the parts of the body back to the heart, less pressure is needed.
Hence, the pressure of the heart is less during the diastolic phase.
The measurement of the normal diastolic blood pressure is around 80 mmHg. It could even be a little less than that.
However, if the pressure of the heart during the diastolic phase is too low, it could be because the body is undergoing severe bleeding or dehydration.
Diastolic Blood Pressure in Various Chambers of the Heart
The diastolic blood pressure is not the same in various chambers of the heart. Let us look at what the pressure is in different parts:
- The right atrium: The pressure in the right atrium should be ideally 0 to 4 mmHg.
- The right ventricle: The diastolic pressure of the right ventricle should be around 4mmHg.
- The left atrium: 10 mmHg is the normal diastolic pressure in the left atrium of the heart.
- The left ventricle: The diastolic pressure of the left ventricle is about 10 mmHg.
- Aorta: The highest diastolic blood pressure is observed in the aorta of the heart. It is around 80 mmHg.
Conclusion
The heart is one of the two most vital organs of the body. The functioning of the heart is carried out by all the chambers of the heart. The heart circulates the blood throughout the body in two faces of the cardiac cycle – the systolic phase and the diastolic phase. In the diastolic phase of the heart, the muscles of the heart are in relaxation. In this state, the pressure of the heart is low. The blood from other parts of the body which is depleted of oxygen is returned to the heart.