WHAT ARE THE DIFFERENCES BETWEEN ATRIA AND VENTRICLES? - ANATOMY AND PHYSIOLOGY - 2025

The atria and ventricles of the heart are the chambers that make up this organ, which is the main organ of the cardiovascular system. The heart is in charge of pumping blood from the blood vessels to the arteries and later to the rest of the body.

This organ receives oxygen-poor blood and sends it to the pulmonary arteries to be purified. Once cleaned, it returns to the heart and from there it is sent to the rest of the body through the circulatory system.

The heart is a hollow muscle tissue that is divided into cavities thanks to a series of membranes. It has four chambers in charge of pumping blood through the circulatory and pulmonary systems.

The upper chambers are called atria and are responsible for receiving blood from blood vessels. The lower ones are called ventricles and are responsible for pumping blood.

The atria

The atria are the upper chambers of the heart, responsible for receiving blood. They are relatively small chambers and the membranes that cover them are really thin since the force they must use to send the blood towards the ventricles is minimal.

Right atrium

The right atrium is one of the four chambers of the heart. This is located in the upper right part of the organ, just above the right ventricle. This chamber receives the deoxygenated blood from the blood vessels.

Deoxygenated blood enters the right atrium through three main veins: the superior vena cava, the inferior vena cava, and the coronary veins.

The superior vena cava carries blood from the tissues that are located above the heart, that is, the tissues of the head, neck, and upper part of the thorax.

For its part, the inferior vena cava carries blood from the tissues that are located below the heart (lower part of the thorax, abdomen and legs). Lastly, the blood drained by the myocardium (heart membrane) is collected by the coronary vein.

The right atrium communicates with the respective ventricle through an atrioventricular orifice that has a valve that allows the passage of blood in only one direction (which prevents blood from returning to the cavity from which it left).

The right valve is called the tricuspid. Similarly, a thin membrane separates the right atrium from the left atrium. This membrane is known as the interatrial septum.

Left atrium

This chamber of the heart receives the purified blood from the lungs and pumps it to the left ventricle.

The left atrium is a small, hollow structure located at the top of the heart. It is separated from the right atrium by the interatrial septum and from the left ventricle by the mitral valve.

While the vena cava, superior and inferior, and the coronary transport the blood towards the right atrium, the blood flow received by the right atrium comes from four pulmonary veins.

Ventricles

The ventricles are the pumping chambers. These cavities are larger than the atria and the membranes that line them are much thicker than those of the atria.

This is because the ventricles must use much greater force than the atria to be able to pump blood to different parts of the body.

Right ventricle

The right ventricle is in charge of pumping deoxygenated blood, coming from the right atrium, towards the trunk or pulmonary artery in order to purify it. It is separated from the left ventricle by the interventricular septum.

Two valves control blood flow through the right ventricle. The tricuspid valve connects this ventricle with the corresponding atrium, which means that it controls the entry of blood into the cavity. The pulmonary valve connects this cavity with the pulmonary arteries, that is, it controls the flow of blood.

Left ventricle

The left ventricle has thicker membranes than the right ventricle because it must pump oxygen-rich blood from the left atrium into the aorta, the largest artery in the body. Thus the blood enters the circulatory system again.

Summary of the Functioning of the Atria and Ventricles

-The atria are the upper chambers of the heart, while the ventricles are the lower

-The atria act as receptors for deoxygenated and oxygenated blood, while the ventricles pump blood from the atria to the pulmonary trunk (in the case of deoxygenated blood) and to the aorta (in the case of oxygenated blood).

-The membranes that cover the atria are thinner than those that cover the ventricles, because the latter must contract with greater force to be able to pump blood to different parts of the body.

-Blood enters the right atrium through the vena cavae.

-The deoxygenated blood passes to the right ventricle through the tricuspid valve.

-The right ventricle pumps blood to the pulmonary trunk, where the blood is purified.

-Oxygenated blood is received by the left atrium and passes to the left ventricle through the mitral valve.

-The right ventricle pumps blood into the aorta.

References

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4. Tony Curran and Gill Sheppard. (October 2011). Module 1: Anatomy and Physiology of the Heart. Retrieved on February 21, 2017, from cdhb.health.nz.
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