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Red Blood Cells and Hemoglobin in Health and in Anemia Disorders

Red blood cells
Red blood cells | Source

Red blood cells, or erythrocytes, are extremely important cells that are abundant in our blood and have vital functions in our bodies. Each erythrocyte is pale red in color and looks likes a doughnut with a hole that hasn't been completely punched through its center.

The red blood cells transport oxygen from our lungs to our tissue cells and are also involved in transporting carbon dioxide waste in the opposite direction. The oxygen is attached to a red pigment in the erythrocytes called hemoglobin. Each of the many trillions of cells in our bodies needs the oxygen delivered by the red blood cells to survive and to do its jobs.

A problem with red blood cells or with hemoglobin will affect our health and can cause many different symptoms. The effects of the red blood cell problem may be minor or they may be more serious. Anemia is the general name given to conditions in which there are not enough healthy red blood cells in the blood or in which there is not enough normal hemoglobin in the blood cells.

What Does Blood Contain?

Production of Red Blood Cells

Bone marrow is found inside bones. There are two types of bone marrow. Red blood cells are made in red bone marrow. Yellow bone marrow contains many fat cells and cannot make red blood cells.

Red bone marrow is found inside every bone of a baby at birth. As we age, some of the red bone marrow is converted into yellow bone marrow. In adults, red bone marrow is found in the breastbone (sternum), the ribs, the shoulder blades, the vertebrae, the skull and the pelvis. Adults also have red bone marrow at the ends of the long bones in the arms and legs. The shafts of the long bones contain yellow bone marrow. In cases of extreme blood loss, yellow bone marrow can be converted into red bone marrow so that more red blood cells can be made.

Red Blood Cells and Anemia

Red Blood Cell Facts

  • A red blood cell is a red, circular disk.
  • The red blood cell is thinner in the middle than at the edge.
  • A mature red blood cell contains no nucleus.
  • There are about 4 to 6 million red blood cells in each cubic millimeter of blood.
  • Men have more red blood cells than women.
  • People living at high altitudes, where there is less oxygen in the air, have more red blood cells than people living at lower altitudes.
  • 20 to 60 seconds are needed for a red blood to circulate around the body.
  • The smallest blood vessels, called capillaries, are so narrow that red blood cells have to be deformed in order to squeeze through them.
  • A red blood cell lives for about 120 days.
  • Every second the red bone marrow makes about 2.5 million red blood cells.
  • About the same number of red blood cells are broken down each second.
  • Old and damaged red blood cells are broken down by the spleen and the liver.

Substances such as oxygen and nutrients leave a capillary and enter the interstitial fluid around cells. Substances such as waste move in the opposite direction.
Substances such as oxygen and nutrients leave a capillary and enter the interstitial fluid around cells. Substances such as waste move in the opposite direction. | Source

Red Blood Cell Functions

Red blood cells contain molecules of a red protein called hemoglobin (or haemoglobin). The hemoglobin gives the cells their color. Each hemoglobin molecule contains iron. The iron in hemoglobin joins with the oxygen that we inhale.

The red blood cells transport the oxygen around the body, delivering it to all the body’s cells. The cells use the oxygen to produce energy. After releasing the oxygen, hemoglobin molecules join to carbon dioxide, which is a waste product made by cells. The red blood cells then carry the carbon dioxide to the lungs to be exhaled.

Red blood cells also contain an enzyme called carbonic anhydrase, which causes some of the carbon dioxide waste that enters the red blood cells to react with water to make hydrogen ions and bicarbonate ions. The hydrogen ions join to the hemoglobin molecules. The bicarbonate ions enter the blood plasma (the liquid portion of the blood) and travel to the lungs. In the lungs, the bicarbonate ions in the blood plasma and the hydrogen ions attached to hemoglobin molecules react to make carbon dioxide and water, which are exhaled.

Normal and abnormal red blood cells; the spiky ones are present in certain diseases and are called acanthocytes
Normal and abnormal red blood cells; the spiky ones are present in certain diseases and are called acanthocytes | Source
A photo of blood cells made with a scanning electron microscope; the red blood cell is on the left, an activated platelet is in the middle and one type of white blood cell is on the right
A photo of blood cells made with a scanning electron microscope; the red blood cell is on the left, an activated platelet is in the middle and one type of white blood cell is on the right | Source

Iron Deficiency Anemia

If someone suffers from anemia there are either not enough red blood cells in the person’s blood or the red blood cells contain an inadequate amount of hemoglobin. There are many types and causes of anemia.

The most common form of anemia is iron deficiency anemia. In this disorder there isn't enough iron available for making new hemoglobin, so the red blood cell count or the amount of hemoglobin in the blood is lower than normal.

Iron-deficiency anemia can be caused by loss of red blood cells due to bleeding, increased need for iron during rapid growth phases or during pregnancy, inability to absorb iron due to small intestine damage, as in celiac disease, or the break down of too many red blood cells (hemolysis), which can be caused by the malaria parasite.

The main symptoms of iron-deficiency anemia are tiredness and weakness. There may also be a range of other symptoms, such as pale skin, shortness of breath, dizziness, headache, a faint feeling, heart palpitations, brittle nails and a sore tongue. In addition, there may be a craving for strange foods, such as ice or dirt. This craving is known as pica.

If you suspect that you have iron-deficiency anemia don’t take iron supplements without seeing a doctor! Too much iron in the body can be very dangerous.

What is Pernicious Anemia?

Intrinsic factor is made in the stomach and binds to vitamin B12. The vitamin is absorbed in the small intestine.
Intrinsic factor is made in the stomach and binds to vitamin B12. The vitamin is absorbed in the small intestine. | Source

Pernicious Anemia Facts

In pernicious anemia, a person’s body is unable to make intrinsic factor. Intrinsic factor is made by cells lining the stomach and binds with vitamin B12 to enable it be absorbed in the small intestine. Vitamin B12 is needed to make hemoglobin, so people with pernicious anemia can't make enough hemoglobin and don't make enough normal red blood cells.

People with all forms of anemia suffer from tiredness and may also experience shortness of breath, heart palpitations, dizziness, headache and pale or yellowish skin. In addition, people with pernicious anemia may develop a thick, smooth and red tongue. Severe vitamin B12 deficiency can cause neurological (nerve) problems. These may include numbness, tingling, muscle weakness, balance problems, difficulty in walking, confusion and memory loss. There may be digestive problems as well, including nausea, vomiting and heartburn.

The word "pernicious" means "deadly". Pernicious anemia used to be fatal but is easily treated today. It's important to visit a doctor if you have any of the symptoms of pernicious anemia, though. A doctor will make a diagnosis and prescribe treatment.

Pernicious anemia is treated with vitamin B12 injections or high dose vitamin B12 pills, depending on the severity of the condition. Sending the vitamin into the body via injection bypasses the need for intestinal absorption. Some vitamin B12 is absorbed through the intestinal lining without intrinsic factor via a process called passive diffusion. When someone ingests a large dose of vitamin B12, their intestine may be able to absorb enough of the vitamin to fulfil their body's needs.

What is Sickle Cell Disease?

Living With Sickle Cell Disease

Sickle Cell Disease Facts

In sickle cell disease, also known as sickle cell anemia, the red blood cells are shaped like a crescent instead of being round, especially when they contain a low amount of oxygen. The red blood cells of a person suffering from sickle cell disease contain abnormal hemoglobin.

Sickled red blood cells are unable to flow through the blood vessels easily and are sticky. If they stick to each other they may interfere with the flow of blood and oxygen. Sickled red blood cells don't live as long as normal red blood cells and die after 10 to 20 days.

Symptoms of sickle cell disease include typical anemia symptoms as well as an experience called a sickle cell crisis, which may happen periodically. During a sickle cell crisis, the abnormal red blood cells block small blood vessels. This interferes with the blood flow to nearby tissues, damaging the cells in the area. In addition, the tissues become swollen and press on nerves, causing pain. Pain-relieving medications can help this situation.

Sometimes a sickle cell crisis occurs for no apparent reason, but some sufferers can link it to a particular trigger, such as dehydration, exercise or a sudden change in body temperature. In these cases avoiding the potential trigger can be very helpful.

Thalassemia - A Cartoon Explanation for Children (and Adults)

Thalassemia Facts

The term “thalassemia” or thalassaemia refers to a group of inherited disorders in which the body has trouble making normal hemoglobin, resulting in a reduced number of red blood cells or smaller than normal red blood cells.

Hemoglobin is a complex molecule. Several genes control its production. The symptoms and seriousness of thalassemia depend on which of the hemoglobin genes are mutated (altered) and on how many of them are mutated. Mild forms of thalassemia may not produce any symptoms and may not need medical treatment. Dealing with the serious forms of thalassemia can be challenging, but treatments are improving.

In addition to typical anemia symptoms, people with thalassemia may experience jaundice (yellow skin), an enlarged liver or spleen and enlarged bones, particularly in the face.

Treatments for severe thalassemia include regular blood transfusions. Frequent blood transfusions cause iron to build up in the body as the red blood cells break down, which is dangerous. A process called chelation is used to remove the excess iron. Some thalassemia patients are prescribed folate supplements.

It's very important that people with any form of anemia visit their doctor regularly. The doctor will be able to recommend the most appropriate treatments for the patient's problems and also monitor their condition. In addition, a doctor will know about new or alternate treatments that are available.

© 2010 Linda Crampton

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Comments 4 comments

Ingenira profile image

Ingenira 5 years ago

Comprehensive information on red blood cells.

I am surprised to know that people living at high altitudes, where there is less oxygen in the air, have more red blood cells than people living at lower altitudes. I wonder whether they will have problem when they move to places at low altitudes ?


AliciaC profile image

AliciaC 5 years ago from British Columbia, Canada Author

Thanks for commenting, Ingenira. Researchers have found that when people who have been living at high altitude travel to a place at low altitude, their red blood cell concentration gradually decreases.


kp 4 years ago

Why is the red blood cell number in males more than in females?


AliciaC profile image

AliciaC 4 years ago from British Columbia, Canada Author

Hi, kp. Testosterone in males stimulates red blood cell production, giving them a higher red blood cell count.

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