What is a red blood cell? Is a lack of red blood cells dangerous?

The article was written by a doctor of Hematology - Blood Transfusion - Laboratory Department - Vinmec Ha Long International General Hospital.

Red blood cells, also known as erythrocytes, erythrocytes, erythrocytes, etc., are the most common type of blood cell and are vertebrates' primary means of delivering oxygen to tissues. body — through blood flow through the circulatory system.

Red blood cells are a type of blood cell whose main function is to carry oxygen. Red blood cells contain Hemoglobin, which is responsible for transporting oxygen from the lungs to the tissues, receiving and transporting CO2 from the tissues back to the lungs for excretion. In many lower animals, hemoglobin is soluble in plasma. In humans, hemoglobin is stored in red blood cells because if it is in the free form in plasma, it gradually percolates through the capillaries and is lost in the urine. As a protein, Hemoglobin also functions as an acid-base buffer, which is also an important function of red blood cells.
Red blood cells are made from hematopoietic stem cells in the bone marrow. Although a single cell, mature red blood cells do not have a nucleus. Antigens on the surface of red blood cells are used to determine blood group. Many blood group systems are known, of which the earliest and most important is the ABO blood group system.
Under the electron microscope as shown below, red blood cells are biconcave disc-shaped with a diameter of about 7.8 μm; The thickest spot is 2.5 μm and no more than 1 μm in the center. The average volume of red blood cells is about 85 - 95 fL. Red blood cells have a very high ability to deform without breaking or tearing as they move through narrow capillaries. This is because the red blood cell membrane is both flexible and has the capacity to contain the components inside.
The number of red blood cells in the blood depends on sex, age, race, geographical area,...
In men: 4.2 - 6.0 T/L. Female: 3.8 – 5.5 T/L. Newborn: 4.5 – 6.0 T/L.

During the first weeks of an embryo's life, nucleated red blood cells are produced in the yolk sac. In the second trimester of pregnancy, the liver (mainly), spleen, and lymph nodes are the red blood cells (nucleated red blood cells). In the last months of pregnancy, only the bone marrow is the place to make red blood cells.
Under 5 years old, almost any bone marrow makes red blood cells. As we age, the marrow of the tubular bones (except the proximal humerus and tibia) gradually becomes fatty and no longer produces red blood cells. After the age of 20, red blood cells are made in the marrow of flat bones (such as vertebrae, sternum, ribs, shoulder blades, pelvis, skull). As we age, the red blood cell function decreases.
Developmental stages of red blood cell line after pluripotent stem cells: Hematopoietic pluripotent stem cells are the source of all types of blood cells, including red blood cells. Pluripotent cells proliferate, some daughter cells will continue to serve as a source of pluripotent stem cells, while most will differentiate through many stages to form lines of red blood cells, white blood cells, and platelets.
The reproduction and development of stem cells are controlled by proteins called hematopoietic promoters, each of which has its own characteristics. Interleukin-3 is a hematopoietic stimulant that affects most blood cell lines, while other hematopoietic stimulants affect only a few cell types.
Hematopoietic and growth promoters have no role in the differentiation of hematopoietic lineages. This is the job of another type of protein - the differentiation promoters. Inducers (differentiation and growth) are produced outside the bone marrow. Reticulocytes cross the blood vessels, leave the bone marrow and enter the circulating blood. Remnants of organelles also dissipate within 1 to 2 days.

On average, a human red blood cell lives for 120 days after leaving the bone marrow and entering the circulating blood. Red blood cells can also be attacked and destroyed by protozoa, typically malaria parasites,... With a life span of only about 120 days, red blood cells are one of the most replaced cell types in humans. body.
Although there is no nucleus, mitochondria and endoplasmic reticulum, in the red cell cytoplasm there are still some enzymes that perform the function of glucose metabolism and produce a small amount of ATP. At the same time, those enzymes also help:
Preserve the elasticity of the red blood cell membrane. Ensures ion exchange across cell membranes. Keeps iron in Hemoglobin as divalent instead of trivalent. Prevents the oxidizing reaction of proteins in red blood cells. However, over time, the metabolism of red blood cells becomes less and less efficient, causing the red blood cell membrane to become fragile and fragile. As a result, old red blood cells will break down as they pass through the cramped organization of the circulatory system, mainly in the spleen and liver. The red marrow of the spleen has a walled structure that most red blood cells must pass through. This structure is only 3 μm wide (while red blood cells are 7.5 μm in diameter). In people who have had their spleen removed, the amount of abnormal red blood cells circulating in the blood is significantly increased.
Destruction of Hemoglobin:
When red blood cells break down and release the contained Hemoglobin, Hemoglobin is almost immediately absorbed by macrophages everywhere in the body but mainly by Kupffer cells in the liver and macrophages in the spleen and bone marrow.
Hours to days later, macrophages will "drop" the iron taken from Hemoglobin back into the blood. Iron is carried to the bone marrow to make new red blood cells or to the liver and other tissues for storage.
The porphyrin component of Hemoglobin, after undergoing a series of transformations, becomes bile iron (ie bilirubin ). This substance follows the splenic vein to the portal vein into the liver, used by the liver to synthesize bile for digestion.

The main function of red blood cells is to carry oxygen and balance the body's alkalinity - acidosis. So, lack of red blood cells will lead to a decrease in the ability to transport oxygen from the lungs to the tissues and reduce the ability to receive CO2 from the organization to the lungs for elimination.
Anemia is a condition in which the blood has a lower than normal number of red blood cells. Anemia can also occur if the red blood cells do not contain enough hemoglobin. Hemoglobin is an iron-rich protein that gives blood its red color. This protein helps red blood cells carry oxygen from the lungs to the rest of the body.
Signs of anemia are fatigue because the body does not receive enough oxygen-carrying red blood cells, weakness and may also have other symptoms such as blue skin, shortness of breath, dizziness, dizziness (especially when changing change positions), or headaches, heart palpitations, children's growth retardation,...
When you have these signs, you need to see a doctor soon for advice and testing. A routine blood test is a simple and common test that checks for normal red blood cells.

The Laboratory Department of Vinmec International General Hospital includes a full range of specialized fields: Biochemistry, Hematology - Blood Transfusion, Microbiology - Parasitology and Pathology with a team of highly qualified and experienced medical professionals. Experience gives the most accurate diagnosis.
All tests are operated according to the standard testing procedures of the Ministry of Health, strict quality control.
Sampling, safe transport of test samples Ensure test quality Return results as soon as possible, actively support doctors for effective treatment Current semi-automatic combined automated testing equipment Modern and synchronous technology of famous and reputable firms in the field of testing in the world such as Beckman Coulter (USA), Roche (Switzerland):
Modern pneumatic system for transporting specimens and returning results by compressed air of Beckman - Coulter company (USA) avoids contamination, confusion of patient samples, and at the same time avoids the impact of the environment on patient samples, giving accurate test results with fast result return time. VITEK2 COMPACT Biormerieux automatic identification and antibiotic system for performing microbiological tests is the system of equipment being used at leading hospitals in Hanoi and Hai Phong. Pathology: The first BenchMark XT automatic in situ hybridization and immunohistochemistry staining machine in Hai Phong identifies the origin and classifies different cancers to help accurately diagnose cancer types.

Reference articles: login.medlatec.vn, vienhuyethoc.vn, bthh.org.vn