How does the human circulatory system work?

Erythrocytes (red blood cells) are nucleated cells that are one of the basic blood cells. They have the shape of a biconcave disk. Their number in the blood depends on many factors, including by age and gender. The main function of red blood cells is to transport oxygen from the lungs, through the heart, to every tissue in the body, and to carry carbon dioxide from the organs into the lungs.

Leukocytes (white blood cells) are nucleated cells. They are less abundant in the blood than erythrocytes, but are nevertheless larger than them. Leukocytes play an extremely important role in the body, they play a defensive role, fighting bacteria, viruses, fungi and parasites. White blood cells are produced in the bone marrow, lymph nodes, thymus and spleen, from where they enter individual organs and tissues through the blood and lymph.

Thrombocytes (platelets) are fragments of other cells – megakaryocytes. They do not have a nucleus in their structure. In terms of size, they are smaller than the rest of the cells in the blood. However, they play a very important role in the body, they take part in the blood clotting process.

Plasma is the liquid part of the blood and consists mainly of water and proteins dissolved in it. In addition, plasma contains glucose, electrolytes and other organic and inorganic components. The role of plasma is to maintain the balance of the internal environment, and due to the presence of antibodies, it plays an important role in defense against pathogenic organisms.

Arteries are blood vessels responsible for carrying blood around the body. Through arteries, blood flows from the heart towards the organs. As your heart beats, your arteries widen and narrow. They owe their elasticity to the elastic connective tissue that builds their walls. The arterial vessels are connected to the venous vessels through capillaries.

The veins are the blood vessels that carry blood to the heart, both oxygenated and deoxygenated. They have thinner and more flaccid walls compared to the walls of the arteries. There are valves in the veins that are designed to prevent the flow of blood flowing backwards.

The bone marrow is the tissue found in the shafts of long bones – as the yellow bone marrow, which plays the role of adipose tissue, and in the epiphyses of long bones – as the red bone marrow that plays the role of hematopoiesis. It is in the red bone marrow that blood cells are formed. The marrow is very well supplied with blood, it contains lymph vessels and nerves.

The spleen is a lymphatic organ located in the left hypochondrium. It plays a very important role in the functioning of the circulatory system. It stores blood and is responsible for removing used and damaged blood cells (erythrocytes, leukocytes and platelets).

Clotting is a process that prevents blood loss that occurs as a result of damage to the continuity of blood vessels. The clotting process consists of many consecutive reactions that lead to the formation of a clot. An existing clot starts the healing process. Clotting is necessary for the proper functioning of the body, without it it would not be possible to stop the bleeding.

Gas exchange is the process of spontaneous transfer of gases (oxygen and carbon dioxide) between the capillaries surrounding the alveolar and the alveolar wall. Oxygen and carbon dioxide are transported in the body through the blood. Oxygen is distributed throughout the body through the blood from the lungs, through the heart, while carbon dioxide collected around the periphery, transported with the blood, through the heart, goes to the lungs.