Circulatory system

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Images, Videos & Interactives

Silhouette diagram of the human body highlighting the heart and major blood vessels, with labeled arteries in red and veins in blue to show the structure of the cardiovascular system.

Diagram showing the human circulatory system with arteries and veins, highlighting the heart, and a detailed cross-section of the heart illustrating blood flow pathways.

Human body systems

Diagram of the human circulatory system showing major arteries in red and veins in blue, with labeled pathways for arterial supply and venous drainage to organs including the heart, lungs, liver, kidneys, intestines, and lower limbs.

Gloved hands hold a blood sample tube above a rack of vials in a laboratory, illustrating blood analysis in human body science.

Illustration of a kidney in cross section showing blood vessels entering and exiting, urine formation, and a detailed callout of a nephron where blood is filtered and urine is produced.

The human heart and cardiovascular system explained

Function of red blood cells explained

Understanding the human cardiovascular system

Learn about the oxygen-transporting function and molecular structure of the protein hemoglobin

At a Glance

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circulatory system summary

Circulatory system: Media

anatomy

Videos

Diagram showing the human circulatory system with arteries and veins, highlighting the heart, and a detailed cross-section of the heart illustrating blood flow pathways.

How Your Circulatory System Works

This system pumps blood from your heart through your body.

Video: Encyclopædia Britannica, Inc.

Gloved hands hold a blood sample tube above a rack of vials in a laboratory, illustrating blood analysis in human body science.

How Much Blood is in the Human Body?

And how much do you really need?

Video: Encyclopædia Britannica, Inc.

The human heart and cardiovascular system explained

The human heart and cardiovascular system explained

The heart, located between the lungs, powers the circulatory system.

Video: Encyclopædia Britannica, Inc.

Function of red blood cells explained

Function of red blood cells explained

In a circuit through the cardiovascular system, red blood cells transport oxygen...

Video: Encyclopædia Britannica, Inc.

Understanding the human cardiovascular system

Understanding the human cardiovascular system

The vascular system is a network of arteries, veins, and capillaries that supplies...

Video: Encyclopædia Britannica, Inc.

Learn about the oxygen-transporting function and molecular structure of the protein hemoglobin

Learn about the oxygen-transporting function and molecular structure of the protein hemoglobin

Hemoglobin is an example of a globular protein. Learn how hemoglobin proteins in...

Video: Encyclopædia Britannica, Inc.

Images

Silhouette diagram of the human body highlighting the heart and major blood vessels, with labeled arteries in red and veins in blue to show the structure of the cardiovascular system.

human circulatory system

Human circulatory system.

Encyclopædia Britannica, Inc.

Diagram of the human circulatory system showing major arteries in red and veins in blue, with labeled pathways for arterial supply and venous drainage to organs including the heart, lungs, liver, kidneys, intestines, and lower limbs.

Human circulatory system

Parts of the human circulatory system that highlight arterial supply and venous drainage...

Encyclopædia Britannica, Inc.

Illustration of a kidney in cross section showing blood vessels entering and exiting, urine formation, and a detailed callout of a nephron where blood is filtered and urine is produced.

human kidney; nephron

Each kidney has approximately one million nephrons, which filter water and other...

Encyclopædia Britannica, Inc.

Human circulatory system. Oxygen-rich blood is shown in red, oxygen-poor blood in blue. The pulmonary circulation consists of the right ventricle and the exiting pulmonary artery and its branches, the arterioles, capillaries, and venules of the lung, and the pulmonary vein. Unlike the other arteries and veins, the pulmonary arteries carry deoxygenated blood and the pulmonary veins carry oxygenated blood. The aorta arises from the left ventricle. The brachiocephalic artery arises from the aorta and divides into the right common carotid and right subclavian arteries. The left and right common carotids extend on either side of the neck and supply much of the head and neck. The left subclavian artery (arising from the aorta) and the right subclavian artery supply the arms. In the lower abdomen, the aorta divides into the common iliac arteries, which give rise to external and internal branches supplying the legs.

Human circulatory system. Oxygen-rich blood is shown in red, oxygen-poor blood in...

© Merriam-Webster Inc.

Interactives

Human body systems

Human body systems

Interactive diagram of the major systems of the body starting with the circulatory...

Encyclopædia Britannica, Inc.

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