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How does the blood circulate around the body? What is the purpose of the veins?

Question:

How does the blood circulate around the body? What is the purpose of the veins?

The Circulatory System:

Our blood is a part of the circulatory system, a major bodily system which is responsible for moving blood throughout the entire body. Blood serves many purposes, including transporting important molecules.

Answer and Explanation:

The blood circulates through the body within blood vessels called arteries, veins and capillaries, and is pumped continuously by the heart. The heart is a strong muscle that automatically undergoes rhythmic contractions in order to push the blood through the vessels to move blood all throughout the body. Arteries are strong, thick-walled blood vessels that carry blood away from the heart, and most arteries carry oxygenated blood. The exception is the pulmonary artery, which carries deoxygenated blood from the heart to the lungs to pick up oxygen. Veins are thinner blood vessels that carry blood back to the heart, and most carry deoxygenated blood. It is the pulmonary vein that carries oxygenated blood from the lungs to the heart to be pumped out to the body. Veins have one-way valves inside them, to ensure that there is no backflow of the blood. The blood serves as a system of transport, carrying oxygen to all cells of the body and also removing carbon dioxide, which is a waste product. Blood also transports nutrients, and carries white blood cells and platelets, which are major components of the immune system.


Learn more about this topic:

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The Human Circulatory System: Parts and Functions

from Biology 105: Anatomy & Physiology

Chapter 13 / Lesson 1
273K

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