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What is Hemoglobin?

Michael Pollick
Michael Pollick
Michael Pollick
Michael Pollick

Hemoglobin is a protein-based component of red blood cells which is primarily responsible for transferring oxygen from the lungs to the rest of the body. It is actually the reason red blood cells appear red, although oxygen-rich blood is noticeably brighter than the depleted blood returning to the heart and lungs. Fresh hemoglobin is produced in the bone marrow as needed.

The creation of this component is controlled by a complicated genetic code. Because unborn babies obtain their oxygenated blood from their mothers and not their own lungs, two separate substances called hemoglobin alpha and gamma combine with several nitrogen atoms and one iron atom. This allows the fetus to receive oxygen-rich blood without respiration. Once the infant is born, however, the body replaces the gamma with a new variant called hemoglobin beta. The combination of these two substances continues for a lifetime.

Hemoglobin makes red blood cells red.
Hemoglobin makes red blood cells red.

Essentially, hemoglobin develops a hunger for oxygen molecules. When the blood is carried into the lungs, the proteins, which contain iron atoms, attract whatever oxygen is available. This oxygenated blood then travels throughout the entire bloodstream, releasing oxygen into the muscles and organs. The spent red blood cells are transferred to the gastrointestinal system for disposal and new red blood cells take their place in the bloodstream.

Hemoglobin allows a fetus to receive oxygen-rick blood without respiration.
Hemoglobin allows a fetus to receive oxygen-rick blood without respiration.

This ongoing system of hemoglobin proteins obtaining oxygen from the lungs and delivering it to the cells is based on ideal conditions, however. Sometimes the alpha or beta proteins produced by the genetic code are not perfectly formed, as in the case of sickle cell anemia. One of the components is shaped like a sickle, causing an imperfect bond to form.

People who smoke regularly may compromise up to 20% of the oxygen supply needed by the lungs.
People who smoke regularly may compromise up to 20% of the oxygen supply needed by the lungs.

Anemia means that the red blood cells lack sufficient levels of iron. Without an iron atom, the damaged hemoglobin pigment cannot attract oxygen in the lungs very effectively, if at all. The result can be a slow wasting process leading to complete body dysfunction.

Hemoglobin can also be compromised by blood conditions such as diabetes or cancer. Many standard blood tests included a general check of hemoglobin levels. The amount of glucose in the bloodstream may vary from hour to hour, but an examination of this component often provides a more accurate reading for diabetics.

Individuals with low hemoglobin levels may be unable to donate blood.
Individuals with low hemoglobin levels may be unable to donate blood.

Another difficulty with hemoglobin is its affinity for gases other than oxygen. It is 200 times more attracted to carbon monoxide than oxygen, for example. This means that someone breathing in carbon monoxide from automobile exhaust could be replacing the oxygen in their lungs with a poison. If enough hemoglobin is exposed to carbon monoxide, the result could be the same as asphyxiation. Cigarette smokers who regularly breath in carbon monoxide could compromise as much as 20% of their total lung oxygen supply.

Most blood tests include a general check of hemoglobin levels.
Most blood tests include a general check of hemoglobin levels.

This attraction to other gases can actually be beneficial under controlled circumstances. It is also attracted to gases used during anesthesia proceedings before surgery. The nitrous oxide or other breathable anesthetic is carried into the brain through the hemoglobin, which allows the surgical team to control the patient's level of consciousness. As oxygen is reintroduced into the patient's lungs, the pigment refreshes itself and the other gases become waste products.

Michael Pollick
Michael Pollick

A regular TheHealthBoard contributor, Michael enjoys doing research in order to satisfy his wide-ranging curiosity about a variety of arcane topics. Before becoming a professional writer, Michael worked as an English tutor, poet, voice-over artist, and DJ.

Learn more...
Michael Pollick
Michael Pollick

A regular TheHealthBoard contributor, Michael enjoys doing research in order to satisfy his wide-ranging curiosity about a variety of arcane topics. Before becoming a professional writer, Michael worked as an English tutor, poet, voice-over artist, and DJ.

Learn more...

Discussion Comments

anon297693

If a person's white and red blood cells are low, his platelets are low and his hemoglobin is low, what could this be a sign of?

anon4795

what is immune-hemoglobin and where does it come from?

anon4080

is carboxyhemoglobin a type of hemoglobin? why is the hemoglobin level low but the hematocrit level is normal.

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    • Hemoglobin makes red blood cells red.
      By: Steve Young
      Hemoglobin makes red blood cells red.
    • Hemoglobin allows a fetus to receive oxygen-rick blood without respiration.
      By: Oleksandr Bondar
      Hemoglobin allows a fetus to receive oxygen-rick blood without respiration.
    • People who smoke regularly may compromise up to 20% of the oxygen supply needed by the lungs.
      By: Photographee.eu
      People who smoke regularly may compromise up to 20% of the oxygen supply needed by the lungs.
    • Individuals with low hemoglobin levels may be unable to donate blood.
      By: Gina Sanders
      Individuals with low hemoglobin levels may be unable to donate blood.
    • Most blood tests include a general check of hemoglobin levels.
      By: spflaum
      Most blood tests include a general check of hemoglobin levels.