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What are the Functions of Blood?

Tricia Christensen
Tricia Christensen
Tricia Christensen
Tricia Christensen

The functions of blood are numerous but can essentially be broken down into two subsets. Blood transports things to the various tissues of the body, and it removes things from the tissues of the body. It may be easiest to think of blood as a never-ending series of light rail cars or trains that travel through an immense transportation network. In this sense, the "cars" are constantly either delivering needed elements or carrying away things produced by the body.

As a delivery system, there are numerous functions of blood. Key among these is to deliver oxygen to all tissues, since no area of the body survives without a regular supply of oxygen. This is not the only thing on the "light rail system" that gets delivered, however. Other things that travel in blood include hormones, nutrients, temperature regulating elements, and various forms of nourishment, such as minerals and vitamins.

One empty and one full pint-sized blood bag.
One empty and one full pint-sized blood bag.

Certain types of blood cells go into action only if the body requires it, and this is one of the major functions of blood. If bacteria enter the body, white blood cells arrive to fight it. An injury requires cells and materials to help clot blood. These cells are not apart from the rest of blood and are constantly traveling with it. Looking at a cut bleeding, people can’t see the cells as different, but under a microscope, it's easy to see there are many elements that make up blood. By all of these elements traveling together, they are ready to work in the ways needed when required, and these additional "as needed" functions could be called special deliveries, based on individual bodily circumstances.

A diagram showing different types of white blood cells.
A diagram showing different types of white blood cells.

It's clear then, that one of the functions of blood is to work as a delivery system, but the transportation network has another important job. It also needs to be able to clear away things the body produces or doesn't need. Various types of waste are carried away by blood and may ultimately be excreted from the body or transformed through chemical processes. Blood must also get rid of excess carbon dioxide so that blood levels retain a normal pH balance.

The different elements that make up blood are visible under a microscope.
The different elements that make up blood are visible under a microscope.

When the functions of blood are suspected as being insufficient or abnormal, one thing doctors may do is perform a complete blood count (CBC) test or other medical tests to determine the efficacy of the cars and the network. Doctors could for instance look at veins and arteries to see if narrowing is creating problems with the "cars" traveling. Alternately, they could look at the blood itself to check it for insufficiencies. Since so much of what bodies are able to do is fully dependent on this vital transportation system, problems with it can be become hugely important and require immediate repair or medical treatment.

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

Learn more...
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

Learn more...

Discussion Comments

anon93673

Love it!

anon80829

very informative and very well put. Thank you.

anon80689

that info was very beautifully explained. i didn't know much about blood but now i do! thank you so much.

anon80639

This sort of thing should be taught as an important subject in all schools. This might reduce the extent of self-harm and disease promotion advertised by alcohol pushers and lousy-food vendors.

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    • One empty and one full pint-sized blood bag.
      By: .shock
      One empty and one full pint-sized blood bag.
    • A diagram showing different types of white blood cells.
      By: apple1
      A diagram showing different types of white blood cells.
    • The different elements that make up blood are visible under a microscope.
      By: WavebreakMediaMicro
      The different elements that make up blood are visible under a microscope.
    • Red blood cells supply oxygen to the tissues and organs of the body.
      By: ag visuell
      Red blood cells supply oxygen to the tissues and organs of the body.
    • Clotting is one function of blood.
      By: clearviewstock
      Clotting is one function of blood.