What is microcirculation

Microcirculation is one of the basic characteristics of life. It is the continuous transmission of material, energy and information between the organism and the surrounding environment. Single-celled organisms can carry out this transmission through the cell membrane, but only the lungs and the stomach and intestines can pass through the trachea and esophagus to carry out the transfer of matter, energy, and information through the cell membrane. The position, function, and metabolism of other organs have been established, and the tissues and cells that make up the organs cannot communicate directly with the external environment. Only the transmission of substances, energy, and information is performed through the tissue fluid, blood, and lymph. Microcirculation is the flow of substances, energy, and blood, lymph, and tissue fluids directly involved in tissues and cells. Since hemoglobin is red, the flow of blood in the arterioles, capillaries, and fine veins can be directly observed under the microscope. Without special treatment, the flow of lymph fluid and tissue fluid can not be seen. Therefore, it is often considered in clinical practice that microcirculation refers to blood microcirculation, and blood microcirculation is a field in which people study more and understand more clearly.

Compared with the general circulation, microcirculation has five characteristics. Understanding these characteristics can give a preliminary understanding of microcirculation.

1. Microcirculation is not only the most distal part of the circulatory system, but also an important component of the organ.

Microvascular and capillary lymphatic vessels are the most distal part of the circulatory system and belong to the circulatory system. The parenchymal cells and tissues of many organs combine organically with arterioles, capillaries, venules, and lymphatic capillaries to form a three-dimensional structure with microvasculature as an important scaffold, so they are also important components of organs.

2. The microcirculation not only has the common features of the vessels but also features the organs.

Microvascular and capillary lymphatic vessels are tubular in shape and facilitate the flow of blood and lymph. However, the morphology and structure of microvessels have their own features in various organs, such as the arrangement, morphology, and structure of the microvessels of the small intestine villi, alveoli, liver, and bone marrow. Even the different parts of the same organ, such as the lymph nodes, spleen, the body and the medulla microvascular morphology have their own characteristics.

3. Microcirculation is not only a pathway for circulation but also a place for material exchange.

Microvasculars are the pathways of circulation. The whole body's circulating blood flows through the microvessels, except for some parts that flow through the branches of arteries and veins, to perfuse tissues and cells. Interstitial fluid exists in the space between tissues and cells and flows between microvessels, cells, and lymphatic capillaries. Capillary lymphatic vessels are one of the important output channels of cells and tissues. Therefore, microcirculation is the place where cells and tissues exchange material with blood and lymph.

4. Microcirculation not only has the common properties of metabolism such as blood vessels, lymphatic vessels, and interstitial space, but also shows some features of the cell metabolism of the organ in which it is located.

5. Microcirculation is not only regulated by systemic nerves and body fluids, but also regulated locally.

In short, the microcirculation is different from the general circulation and has “duality”, that is, in terms of attributes, morphology, function, metabolism, and regulation, both the generality of the general circulatory system and the specificity of organs.