Erythrocytes (red blood cells): characteristics and function

Erythrocytes, also called red blood cells or red blood cells, are the most common cells in the bloodstream. They are fundamental anatomical units for all of our vital functions. Among others they carry oxygen and distribute nutrients throughout the body.

We will see below what erythrocytes are, how they are produced and what are their main functions.

    What are erythrocytes?

    Erythrocytes are the red blood cells that make up our blood. In fact, the term “erythrocyte” comes from the Greek “erythros” meaning red, and “kytos” meaning cell.

    Also called red blood cells, erythrocytes are one of the main components of the bloodThe functions are essential to maintain the various systems of our body. To analyze this in more detail, at the beginning we will see what blood is and what are its functions and components.

    Blood and its main components

    Blood is the fluid that passes through our body, its composition is thicker than water, slightly viscous, and its average temperature is 38 ° C (one degree higher than body temperature). The amount in liters of blood that each of us has largely depends on our height and weight.

    Its main functions include transporting oxygen from the lungs to body cells, transporting hormones, supplying cells with specific nutrients, removing waste and keep the body in natural balance (For example, pH and temperature levels).

    On the other hand, there are many cells that make up this fluid. 55% of blood is plasma, a slightly yellow liquid that is in turn 90% water and 10% protein, electrolytes, vitamins, glucose, amino acids, and other nutrients. The remaining 45% of our blood is made up of different types of cells.

    99% of this other half is made up of red blood cells which we call red blood cells or erythrocytes. The rest (1%) are white blood cells, also called leukocytes; and platelets, Also known as platelets. Thus, 84% of all cells in the human body are erythrocytes.

      Functions of red blood cells

      Erythrocytes appear as small discs with cracks. They are flexible, which means they can bend easily to flow through narrower blood vessels.

      Unlike other cells, erythrocytes do not have a nucleus. What they have is hemoglobin, A protein responsible for transporting oxygen in the blood, and is also responsible for the red color of the blood. Among the main functions of erythrocytes are:

      • Collect oxygen from the air we breathe in and carry it through the blood vessels in the lungs to all parts of the body.
      • This is the process required for cell metabolism, in turn generating carbon dioxide as a residue.
      • They collect carbon dioxide and return it to the lungs, Allowing us to expel it on expiration.
      • They release hydrogen and nitrogen, which helps keep blood pH stable.
      • Thanks to the above, the blood vessels dilate and the blood pressure decreases.

      On the other hand, the deficit in the production of erythrocytes, or their accelerated destruction, this is what causes anemia; while an excess in the production of these cells generates polycythemia or erythrocytes.

      Blood cell production process

      Stem cells are responsible for making the strongest parts of the blood. From multi-stage development, stem cells become blood cells or platelets.

      At the end of their development, they are released into the bloodstream, which it maintains a certain number of precursor cells which allows its regeneration. The latter process is regulated by substances: the hormone erythropoietin (produced in the kidneys) is responsible for the production of red blood cells, and cytokines help in the production of white blood cells.

      Glucose is essential for their metabolism (because they don’t have a nucleus or mitochondria), so some of the main pathways are glycolysis and the hemoglobin reductase pathway.

      In adults, most blood cells they occur in the bone marrowAlthough in the case of erythrocytes, especially lymphocytes, maturation occurs in the lymph nodes.

      Erythrocytes have a life cycle of approximately 120 days. After this time, they break down in the bone marrow, spleen, or liver, through a process called hemolysis. In this process they are preserved building blocks of erythrocytes, such as iron and globin, which are then reused.

      Bibliographical references:

      • Capellera-Garcia, S. and Flygare, J. (2016). Definition of the minimum factors required for erythropoiesis by direct line conversion. Rep. Cell, 14-15 (11): 2550-2560.
      • Etymology of erythrocytes (2018). Etymologiasdechile. Accessed October 17, 2018.Available at
      • Erythrocytes (red blood cells) (2014). National Cancer Institute. Accessed October 17, 2018.Available at
      • What does the blood do? (2015). United States National Library of Medicine. Accessed October 17, 2018.Available at

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