What Is The Red Blood Cells Function – Home Quizzes & Games History & Society Science & Technology Biographies Animals & Nature Geography & Travel Arts & Culture Videos Money

Although every effort has been made to follow the rules of citation style, there may be some discrepancies. Please refer to the appropriate style manual or other source if you have any questions.

What Is The Red Blood Cells Function

Encyclopaedia Editors Encyclopaedia’s editors oversee subject areas in which they have extensive knowledge, either from years of experience gained by working on the content or through study for an advanced degree. They write new content and verify and edit content received from contributors.

Question Video: Matching The Correct Component Of The Blood To It’s Function

Red blood cells, also called erythrocytes, the cellular component of blood, millions of them in the circulation of vertebrates give blood its characteristic color and carry oxygen from the lungs to the tissues. Mature human red blood cells are small, round, and biconcave; it appears dumbbell-shaped in profile. These cells are flexible and have a bell shape as they pass through very small blood vessels. It is covered with a membrane composed of lipids and proteins, has no nucleus, and contains hemoglobin—a red iron-rich protein that binds oxygen.

Notice how red blood cells travel from the heart to the lungs and other body tissues to exchange oxygen and carbon dioxide

The function of red cells and their hemoglobin is to carry oxygen from the lungs or gills to all body tissues and carry carbon dioxide, a waste product of metabolism, to the lungs, where it is excreted. In invertebrates, oxygen-carrying pigments are carried freely in the plasma; its concentration in red cells in vertebrates, so that oxygen and carbon dioxide are exchanged as gases, is more efficient and represents an important evolutionary development. Mammalian red cells are further adapted to lack a nucleus—the amount of oxygen the cell needs for its own metabolism is very low, and most of the oxygen it carries can be released into the tissues. The biconcave cell shape allows oxygen exchange at a constant rate over the largest possible area.

Red cells develop in the bone marrow in several stages: from the hemocytoblast, a multipotent cell in the mesenchyme, it becomes an erythroblast (normoblast); during two to five days of development, the erythroblast gradually fills with hemoglobin, and its nucleus and mitochondria (particles in the cytoplasm that provide energy for the cell) disappear. In the final stage cells are called reticulocytes, which eventually become fully mature red cells. The average red cell in humans lives 100–120 days; there are about 5.2 million red cells per cubic millimeter of blood in an adult human.

Functions Of Blood: Transport Around The Body

Although red cells are usually round, a small proportion are oval in normal people, and in certain hereditary conditions a higher proportion may be oval. Some diseases also present red cells with an abnormal shape—eg, oval in pernicious anemia, crescent-shaped in sickle cell anemia, and with projections giving a spiny appearance in the hereditary disorder acanthocytosis. The number of red cells and the amount of hemoglobin varies between different individuals and under different conditions; the number is higher, for example, in people living at high altitudes and in polycythemia. At birth the number of red cells is high; it falls shortly after birth and gradually increases to adult levels during puberty. Erythrocytes, commonly known as red blood cells (or RBCs), are by far the most commonly formed element: A drop of blood contains millions of erythrocytes and only thousands of leukocytes. In particular, men have about 5.4 million erythrocytes per microliter (

L. In fact, erythrocytes are estimated to make up about 25 percent of the total cells in the body. As you can imagine, they are relatively small cells, with an average diameter of only about 7–8 micrometers (

M) (Figure 1). The main function of erythrocytes is to take oxygen inhaled from the lungs and transport it to the tissues of the body, and to take part (about 24 percent) of the residual carbon dioxide in the tissues and transport it to the lungs to be exhaled. Erythrocytes remain in the vascular network. Although leukocytes normally leave the blood vessels to perform their defense function, the movement of erythrocytes from the blood vessels is abnormal.

When erythrocytes mature in the red bone marrow, they extrude their nucleus and most of their other organelles. During the first day or two they are in circulation, immature erythrocytes, known as reticulocytes, usually still contain organelle remnants. Reticulocytes should comprise approximately 1-2 percent of the erythrocyte count and provide a rough estimate of RBC production rates, with abnormally low or high rates indicating abnormalities in the production of these cells. These remnants, especially the network (reticulum) of ribosomes, are quickly removed, however, and mature, circulating erythrocytes have few internal cellular structural components. For example, lacking mitochondria, they rely on anaerobic respiration. This means they don’t use up any of the transported oxygen, so they can deliver it all to the tissues. They also lack endoplasmic reticulum and do not synthesize proteins. However, erythrocytes contain several structural proteins that help blood cells maintain their unique structure and allow them to change shape to squeeze through capillaries. These include the protein spectrin, a cytoskeletal protein element.

Not Enough Blood — Doctor K Private Medicine

Figure 2. Shape of Red Blood Cells Erythrocytes are biconcave discs with a very shallow center. This shape optimizes the ratio of surface area to volume, facilitating gas exchange. It also allows them to fold as they move through narrow blood vessels.

Erythrocytes are biconcave discs; that is, they are fat at the edges and very thin in the middle (Figure 2). Because they lack most organelles, there is more internal space for the presence of hemoglobin molecules which, as you will see shortly, transport gases. The biconcave shape also provides a larger surface area where gas exchange can occur, compared to its volume; spheres with similar diameters will have a lower surface area to volume ratio. In the capillaries, the oxygen carried by the erythrocytes can diffuse into the plasma and then pass through the capillary walls to reach the cells, while part of the carbon dioxide produced by the cells as a waste material diffuses into the capillaries to be taken up by the erythrocytes. Capillary beds are very narrow, slowing the passage of erythrocytes and providing a longer opportunity for gas exchange to occur. However, the space in a capillary can be so small that, despite its small size, erythrocytes may have to fold in on themselves if they want to pass through. Fortunately, their spectrin-like structural proteins are flexible, allowing them to bend to surprising degrees, then spring back as they enter wider vessels. In wider vessels, erythrocytes may be arranged like a roll of coins, forming rouleaux, from the French word for “roll.”

Hemoglobin is a large molecule composed of protein and iron. It consists of four folded chains of proteins called globins, designated alpha 1 and 2, and beta 1 and 2 (Figure 3a). Each of these globin molecules is bound to a red pigment molecule called heme, which contains iron ions (Fe

Figure 3. (a) One hemoglobin molecule contains four globin proteins, each of which is bound to one molecule of the iron-containing pigment heme. (b) One erythrocyte can contain 300 million molecules of hemoglobin, and thus more than 1 billion molecules of oxygen.

Blood Structure And Its 3 Main Circulatory Functions In The Body

Each iron ion in heme can bind to one oxygen molecule; therefore, each hemoglobin molecule can transport four oxygen molecules. An individual erythrocyte may contain about 300 million hemoglobin molecules, and therefore can bind and transport up to 1.2 billion oxygen molecules (see Figure 3b).

In the lungs, hemoglobin takes up oxygen, which binds to iron ions, forming oxyhemoglobin. Bright red, oxygenated hemoglobin travels to body tissues, where it releases some of its oxygen molecules, becoming dark red deoxyhemoglobin, sometimes referred to as reduced hemoglobin. The release of oxygen depends on the oxygen demand of the surrounding tissues, so hemoglobin rarely gives up all of its oxygen. In the capillaries, carbon dioxide enters the bloodstream. About 76 percent dissolves in plasma, some of which remains as dissolved CO

, and the rest form bicarbonate ions. About 23–24 percent of it binds to amino acids in hemoglobin, forming a molecule known as carbaminohemoglobin. From the capillaries, hemoglobin carries carbon dioxide back to the lungs, where it releases it for oxygen exchange.

Changes in RBC levels can have a significant impact on the body’s ability to effectively deliver oxygen to tissues. Ineffective hematopoiesis results in an insufficient number of RBCs and results in one of several forms of anemia. Excessive RBC production results in a condition called polycythemia. The main disadvantage with polycythemia is not the failure to deliver enough oxygen directly to the tissues, but rather the increased viscosity of the blood, which makes it more difficult for the heart to circulate blood.

Red Blood Cell

In patients with

What is the main function of the red blood cells, what is the function of stem cells, what is the function of hemoglobin in red blood cells, what is red blood cells function in the body, what is the function of skin cells, red blood cells function, what is the function of goblet cells, what is the function white blood cells, what is the function of t cells, what is the function of basal cells, what is the function of mast cells, what is the function of b cells