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What Is The Difference Between Systole And Diastole?

We explain that what is the difference between systole and diastole? in detail. Main differences between systole and diastole with definitions, characteristics, types and function and comparison table to easily understand.

What Is The Difference Between Systole And Diastole?

The terms systole and diastole refer to two stages of the cardiac cycle . These are cycles that occur when the heart beats to pump blood to the rest of the body. In this article we address all the differences between these two cardiac stages.

The heart is one of the most important or prominent organs of the human body. Understanding how it works can be daunting because it is a kind of piece of machinery that works so precisely that the slightest failure of it can result in death.

The heart works like a pump. Its job is to pump blood through veins and arteries , so that it is distributed throughout the body. The human heart has four chambers, the right atrium and left atrium (upper) and the right ventricle and left ventricle (lower).

Among its most basic processes, the two phases of the cardiac cycle (heartbeat) are known as systole and diastole. As a curious fact, the cardiac cycle lasts about a second and does not stop until the moment of death. However, what can change is the frequency, depending on whether the individual is at rest or not.

Systole and diastole are two stages of the cardiac cycle. Systole is the contraction phase of the heart, where blood is pumped into the vessels, and diastole is the relaxation phase, which allows blood to enter the heart.

In a normal adult, the average systolic pressure is 120 millimeters of mercury (mmHg), while the diastolic is 80 mmHg.

Diastolic pressure occurs early in the cardiac cycle. It is the minimum pressure in the arteries when the pumping chambers of the heart fill with blood. Systolic pressure occurs at the end of the cardiac cycle, when the ventricles contract.

What Is Systole?

The part of the cardiac cycle that consists of the expulsion of blood from the heart to the rest of the body is known. And just like a pump, it expels water from one container to another through pipes.

In this way, the arteries efficiently transport blood to the rest of the body’s organs and tissue.

Types Of Systole

Ventricular systole : is a process where the heart muscle tissue of the ventricle contracts. The contraction causes an increase in the pressure within the ventricles and the exit of the blood that is contained in them.

Atrial systole : in this process, contraction occurs in the atrial muscle tissue of the heart. Which causes increased pressure in the atrial heart chamber. In this way, the blood volume increases, the contraction of the atria. This allows blood to reach the ventricles, through the atrioventricular valves, and causes blood to flow through the arteries to the lungs or other parts of the body.

Systole Characteristics

The blood is driven by the contraction of the ventricles, it travels through the atria (upper spaces of the heart) and later out through the main arteries.

This is mainly characterized by determining what is popularly known as “high blood pressure” or systolic, which must be within the range of 95-120 mmHg.

It is worth mentioning that systole will always be greater than diastole (which we will talk about later) since it drives the blood using the heart muscles.

In addition, most of the conditions of the human body are related to cardiac tension (systole and diastole), where there is a very strong commercial pharmaceutical component behind.

What Is Diastole?

It is the phase of the cardiac cycle that includes the “collection” of blood from the tissues and organs to the heart by the veins. It is also known as a “relaxation phase”, because the heart does not contract (in systole it does).

Also in this stage the heart is nourished along with the lungs (something that happens in systole). Being both the heart and the lungs, the only organs that benefit from the blood supply at this stage.

So, The diastole is the relaxation condition in which comes to meet the heart , especially the ventricles, comprising the time between two heart systole and also between the closing of the aortic, pulmonary, atrioventricular mitral and tricuspid. Diastolic pressure begins with the cardiac cycle, it is said to be low pressure and its normal measurement is 80 (mmHg) in adults, who do not present health alterations for any reason.

Characteristics Of Diastole

Its main characteristic is its blood pressure level considerably lower than diastole, due to the fact that there is not a “pump impulse”, but a phase of collecting blood towards the heart again.

It is also important to note that diastole does not use any force to bring blood back to the heart, making it a passive activity.

All this while carbon dioxide is collected from the blood from other organs and tissues to collect it in the lungs, after having passed through the cardiac atria and being expelled during respiration (exhalation).

In this way, diastole works both to irrigate the last organs of the body, and to collect all the waste from it through the bloodstream.

Systole and Diastole are functions that belong to the heart. They are two very important phases of the heart; These processes allow blood to enter and exit the heart. It is necessary to take care of the organ (heart) so that the processes are executed properly. But how are they different?

what is the difference between systole and diastole

Blood Pressure Reading

The blood pressure reading is measured in millimeters of mercury (mmHg) and is supplied in two numbers.

The highest number is the systolic blood pressure reading , which represents the maximum pressure exerted when the heart contracts.

The lowest number is the diastolic blood pressure reading , which represents the minimum pressure in the arteries when the heart is at rest.

So if the doctor says your pressure is 120 by 80, it means that in systole it is 120 mmHg and in diastole it is 80 mmHg.

As for the heartbeat, which can be heard with a stethoscope, the first beat marks the onset of systole, and the second is the onset of diastole.

What Are The Normal And Abnormal Values ​​Of Systolic And Diastolic Pressure?

In children, the systolic pressure is between 95 and 100 mmHg and in adults it is between 90 and 120 mmHg. But, the diastolic measurement in children is 65 mmHg, and in adults it is 60 to 80 mmHg. However, there are cases where these values ​​are altered and can be a danger to the patient. As for example is the case in adults of:

Hipotension : is when the systolic reading indicates a value less than 90 mmHg and / or the diastolic less than 60 mmHg;

Pre hypertension : in this case the systolic reading is above 121 to 139 mmHg and the diastolic is between 81 to 89 mmHg;

First stage hypertension : case where the systolic reading is between 140 to 159 mmHg and the diastolic is 90 to 99 mmHg;

Second stage hypertension : this is when the systolic reading is 160 mmHg and the diastolic reading is 100 mmHg.

what is the difference between systole and diastole

Key Differences Between Diastole And Systole

  • Systole consists mainly of “pushing” blood out of the heart; while diastole recovers it.
  • Systole carries blood to all tissues and organs in the body except the heart and lungs. In contrast, in diastole the latter are nourished by blood supply.
  • Diastole is considered “low pressure”, while systole is called “high pressure”.
  • Diastole-related conditions are more dangerous than systole, but all must be treated.
  • In diastole more use is made of veins than arteries. In contrast, systole uses more of the latter for irrigation.

The Sístole allows the heart to contract and let out blood to reach the vessels. In diastole , the heart relaxes and thus blood enters the heart.

Comparative Table

Systole Diastole
What is it? It is the active and powerful phase of the heartbeat. In this the heart contracts, pumping blood to the pulmonary arteries and the aorta. Instead, diastole is the relaxation phase. During this, the muscular walls of the heart relax, allowing the chambers to fill with blood.
Function The heart contracts by pumping blood from the heart to the aorta and pulmonary artery. The heart relaxes allowing the heart chambers to be filled with blood, which comes from the pulmonary veins and vena cavae.
Direction of blood Blood is expelled from the heart. In contrast, in diastole, blood enters the heart.
Medium pressure The recommended systolic pressure for a normal adult is 120 mmHg. For a child it is 100 mmHg (6 to 9 years). The recommended diastolic pressure for a normal adult is 80 mmHg. For children it is 65 mmHg.
Blood vessels Contracted. Relaxed.
Blood pressure reading The highest number is the systolic pressure. The lowest number is the diastolic pressure.
Phases The systole process is divided into atrial systole and ventricular systole. Similarly, diastole is divided into atrial diastole and ventricular diastole.

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