Circulatory system: Quick Facts

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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 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.

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 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.

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.

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

The human heart and cardiovascular system explained

Function of red blood cells explained

Understanding the human cardiovascular system

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Topics

blood vascular system milieu intérieur blood lymphatic system lymph circulation hemocoel closed vascular system lymphatic vessel ostium muscle nervous system immune system Respiratory system Integument Endocrine system mucous membrane gland human ear Physiology

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Key People

Galen of Pergamum

Galen

Greek physician

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André F. Cournand

American physiologist

Superficial arteries and veins of face and scalp, cardiovascular system, human anatomy, (Netter replacement project - SSC)

The Human Body

3d illustration human heart. Adult Anatomy Aorta Black Blood Vessel Cardiovascular System Coronary Artery Coronary Sinus Front View Glowing Human Artery Human Heart Human Internal Organ Medical X-ray Myocardium

Human Organs