Human blood consists of cells and a liquid part, or serum. The liquid part is a solution that contains a certain amount of micro and macro elements, fats, carbohydrates and proteins. Blood cells are usually divided into three main groups, each of which has its own structural features and functions. Consider each of them more closely.
Red blood cells, or red blood cells
Red blood cells are rather large cells that have a very characteristic biconcave disc shape. Red bodies do not contain a nucleus - a hemoglobin molecule is located in its place. Hemoglobin is a rather complex compound, which consists of the protein part and the ferrous atom. Red blood cells form in the bone marrow.
Red blood cells have many functions:
- Gas exchange is one of the main functions of the blood. It is hemoglobin that takes direct part in this process. In small pulmonary vessels, the blood is saturated with oxygen, which combines with the hemoglobin iron. This connection is reversible, therefore oxygen remains in those tissues and cells where it is needed. At the same time, with the loss of one oxygen atom, hemoglobin combines with carbon dioxide, which is transferred to the lungs and excreted into the environment.
- In addition, on the surface of red blood cells there are specific polysaccharide molecules, or antigens, that determine the Rh factor and blood group.
White blood cells, or white blood cells
White blood cells are a fairly large group of different cells whose main function is to protect the body from infections, toxins and foreign bodies. These cells have a nucleus, can change their shape and pass through tissue. They are formed in the bone marrow. White blood cells are usually divided into several separate types:
- Neutrophils are a large group of white blood cells with the ability to phagocytosis. Their cytoplasm contains many granules filled with enzymes and biologically active substances. When bacteria or viruses enter the body, the neutrophil moves to a foreign cell, captures it and destroys it.
- Eosinophils are blood cells that perform a protective function by destroying pathogens through phagocytosis. They work in the mucous membrane of the respiratory tract, intestines and urinary system.
- Basophils are a small group of small oval cells that take part in the development of the inflammatory process and anaphylactic shock.
- Macrophages are cells that actively destroy viral particles and bacterial cells, but have granule clusters in the cytoplasm.
- Monocytes - are characterized by a specific function, as they can either develop, or, conversely, inhibit the inflammatory process.
- Lymphocytes are white blood cells responsible for the immune response. Their peculiarity lies in the ability to form resistance to those microorganisms that have already penetrated human blood at least once.
Blood platelets, or platelets
Platelets are small, non-nuclear human blood cells of an oval or round shape. After activation, protrusions form on the outer membrane of the cell , as a result of which it resembles a star.
Platelets perform a number of rather important functions. Their main purpose is the formation of the so-called blood clot. It is the platelets that first enter the site of injury, which, under the influence of enzymes and hormones, begin to stick together, forming a thrombus. This clot clogs the wound and stops the bleeding. In addition, these blood cells are responsible for the integrity and stability of the vascular walls.
We can say that blood is a rather complex and multifunctional kind of human connective tissue, designed to maintain normal life.