What are the Main Functions of Blood?

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From childhood cuts to Vampire films, everyone knows what blood looks like outside of the body: bright, red, and runny. But what exactly does blood do?

Blood is actually very hard at work within the body. The primary responsibility of blood is transportation: the blood delivers oxygen from the lungs to the cells of the body, transports carbon dioxide produced in the body back to the lungs for exhalation, transports critical nutrients and hormones to cells, and removes waste products. However, blood also works to maintain the overall function of the body via protection mechanisms and regulation functions. Learn more about the functions of blood below!

Protection: Blood plays a critical role in defending the body against external and internal threats to overall health and wellness. Some white blood cells within the blood work to protect the body from disease-causing bacteria entered into the bloodstream through an open wound, while others seek out and eradicate harmful body cells infected with viruses or cells with mutated DNA that could potentially cause cancer. Platelets in the blood also initiate clotting at the site of an injury to prevent harmful amounts of blood loss.

Regulation: Blood helps regulate and maintain the proper temperature within the body. When we are too hot, blood vessels become wider and allow more blood to flow through the skin, which causes more heat to be lost. Blood vessels leading to the skin capillaries become wider allowing more blood to flow through the skin and more heat to be lost to the environment. This is called vasodilation. When we are too cold, blood vessels constrict – which allows less blood to flow through the skin and conserves the core body temperature. This is called vasoconstriction. Blood also helps regulate proper pH and water levels within the body.

As you can see, blood plays a critical role in keeping your body safe, healthy, and functioning properly. Good thing you have around 1.5 gallons of blood inside of you!


Khan Academy: https://www.khanacademy.org/science/biology/human-biology/circulatory-pulmonary/a/components-of-the-blood

Medical News Today: https://www.medicalnewstoday.com/articles/196001

Texas Heart Institute: https://www.texasheart.org/heart-health/heart-information-center/topics/blood/