Review of Red Blood Cell Structure and Function

Red blood cells (RBCs) are the most abundant cells in the human body and play an essential role in oxygen delivery, carbon dioxide removal, and other vital functions. They are also known as erythrocytes and are the major components of the blood. RBCs are flat, biconcave discs with a diameter of 7.2 – 8.2 µm and a thickness of 2.2 µm. A review of their structure and function is necessary for understanding the pathology of various diseases.

Structure of Red Blood Cells

The normal red blood cell is composed of a plasma membrane, an anucleate cytoplasm, and an array of proteins and enzymes. The membrane consists of a phospholipid bilayer with embedded proteins, glycoproteins, and enzymes. The most abundant protein in RBCs is the globin molecule, which is composed of two alpha and two beta polypeptide chains. The globin molecule binds to oxygen and functions as an oxygen transporter.

The cytoplasm of RBCs consists mainly of hemoglobin, and other proteins such as carbonic anhydrase, spectrin, and other enzymes. Hemoglobin is a protein composed of four globin chains and four heme groups. Each heme group contains one atom of iron, which can bind to oxygen molecules. The oxygenated hemoglobin is known as oxyhemoglobin, and the deoxygenated form is called deoxyhemoglobin.

Function of Red Blood Cells

The primary function of RBCs is to transport oxygen and carbon dioxide from the lungs to the tissues. The hemoglobin present in the cell binds to oxygen in the lungs and is then transported to the tissues. Oxygen is then released from the hemoglobin, and the deoxygenated hemoglobin binds to carbon dioxide and transports it back to the lungs. The hemoglobin also functions as an acid-base buffer, helping to maintain a normal pH level in the body.

RBCs also play a role in immunity by transporting immunoglobulins to the tissues. They also contain enzymes that are involved in the breakdown of various substances, such as glucose, amino acids, and lipids. These enzymes also play a role in the production of energy.

Pathology of Red Blood Cells

Red blood cell disorders can be caused by a variety of factors, including genetic mutations, environmental toxins, and nutritional deficiencies. Common disorders include anemia, sickle cell anemia, thalassemia, and spherocytosis.

Anemia is a condition characterized by a decrease in the number of red blood cells or hemoglobin levels. It can be caused by a variety of factors, including nutritional deficiencies, bleeding, and certain medications. Symptoms of anemia include fatigue, pale skin, shortness of breath, and dizziness.

Sickle cell anemia is a genetic disorder caused by a mutation in the hemoglobin gene. It is characterized by abnormal red blood cells that form a sickle shape, causing them to be less flexible and more prone to breaking. This can lead to a decrease in the amount of oxygen that is transported to the tissues, resulting in symptoms such as fatigue, pain, and an increased risk of infection.

Thalassemia is another genetic disorder that affects the production of hemoglobin. It is characterized by a decrease in the production of one of the globin chains, resulting in an abnormal hemoglobin structure. Symptoms include fatigue, anemia, and bone deformities.

Spherocytosis is a disorder characterized by red blood cells that are abnormally spherical in shape. This can cause decreased flexibility and an increased risk of hemolysis. Symptoms include jaundice, fatigue, and anemia.

In conclusion, red blood cells are the most abundant cells in the human body and play an essential role in oxygen delivery, carbon dioxide removal, and other vital functions. A review of their structure and function is necessary for understanding the pathology of various diseases. Anemia, sickle cell anemia, thalassemia, and spherocytosis are some of the most common red blood cell disorders.