What are lymph nodes? You will find an exhaustive answer to the question asked in the materials of the article. In addition, we will talk about the structure of the presented organ, as well as the causes of its inflammation, possible consequences, and so on.
General information
What are lymph nodes? A lymph node is a peripheral organ of the lymphatic system that acts as a natural filter. Through it flows all the lymph coming from various parts and organs of the body. In the human body, there are several groups of such nodes, which are called regional.
Size of lymph nodes
Externally, lymph nodes look like round, oval, bean-shaped or sometimes ribbon-like formations. Their sizes vary from 0.5 to 50 mm or more. As you know, such peripheral organs are painted in a grayish-pink color. Lymph nodes are located only along the lymphatic vessels and are located in clusters of up to ten pieces near large veins and blood vessels.
Appearance
Lymph nodeshuman are covered with a connective tissue membrane, from which so-called trabeculae or beams extend into the organ. They are a kind of supporting structures. It should be especially noted that the peripheral organ itself, which performs the function of a natural filter, consists of stroma. It is formed from reticular connective tissue, on which there are process cells that form a three-dimensional network. In addition, the stroma consists of phagocytic substances (or macrophages), represented in the lymph nodes by several varieties.
Internal structure of the lymph node
On the incision of the lymph nodes, two main zones are immediately distinguished. Closer to the shell is the cortical substance. It distinguishes between the superficial part and the region of the deep cortex (or the so-called paracortical layer). The medulla is referred to the internal zone of the lymph node.
The entire space of this organ is filled with lymphoid tissue. In the zone of the superficial cortex, which is closer to the shell, there are small nodules or follicles. It should be noted that they have a central light part (germinal center), where differentiation of B-lymphocytes and antigen-dependent proliferation occurs, as well as a dark superficial part, which contains a large number of closely spaced and rather small lymphocytes.
Working principle
In the paracortical zone, lymphocytes are distributed evenly and very densely. T-lymphocytes predominate in this part of the organ. Here they undergo antigen-dependent differentiation andproliferation. As for the medulla, the accumulations of lymphoid tissue in it are represented by medullary cords (or pulpy cords), where B-lymphocytes migrate from the superficial cortex.
The principle of operation of this peripheral organ is as follows: lymph flows to the nodes through vessels suitable from the convex side, and flows out through the outflowing vessels from the concave side. At the same time, inside the node, lymph seeps rather slowly through spaces called sinuses. They are located between the sheath and trabeculae, as well as lymphoid tissue.
Just like the vessels, the internal space of the node has its own lining, which is formed by littoral or coastal cells. As a rule, their processes go inside the sinus, where they begin to contact the reticular cells. It should be especially noted that, unlike ordinary vessels, the sinuses do not have a free cavity, because it is completely blocked by a three-dimensional network. Due to this structure, the lymph, getting into the node, slowly seeps out, which contributes to its thorough cleansing of foreign bodies. Also, this process occurs due to macrophages located along the very edge of lymphoid accumulations. By the way, while passing through the sinuses (medulla), the lymph is fully saturated with antibodies that produce cord (brain) plasma cells.
What are the lymph nodes for?
What are lymph nodes, we found out. Now I want to talk about why these organs are needed at all. The fact is that the flowing lymphbrings so-called foreign antigens into the node. As a result, this leads to the development of immune response reactions in the organs. Depending on the type and nature of foreign bodies, such reactions can actively develop in external or internal zones. This leads to a barely noticeable or strong increase in the size of the nodes. Thus, it can be safely noted that the presented peripheral organs are a kind of barrier to the spread of not only various infections, but also a cancerous tumor. After all, protective cells are able to mature in the node, which take an active part in the destruction of foreign antigens and other substances.
Where are the lymph nodes located?
Lymph nodes (photos are presented in this article) are in the human body in fairly large groups, of which there are about ten pieces. They are located so as to prevent the development of various infections and cancerous tumors. It is for this reason that the nodes are located near the most important organs and systems for life, namely in the elbow and knee folds, in the armpits and inguinal region. In addition, they are located in the neck, chest and abdominal cavity. Thus, the lymph nodes provide complete protection against various infections and tumors of the head.
Types of lymph nodes
It should be especially noted that such a filtering system is not only in the above places. Lymph capillaries permeate all internal organs. At the same time, they perform the same functions.
So, there are several groups in the human bodylymph nodes, namely:
- intrathoracic;
- bronchopulmonary;
- elbow;
- splenic;
- para-aortic;
- mesenteric;
- iliac (external, internal, and general);
- inguinal (superficial and deep);
- femoral;
- hamstrings.
Why do my lymph nodes get enlarged?
The causes of enlarged lymph nodes are a variety of diseases. At the same time, it should be especially noted that the bump that appears indicates the trouble of the particular zone in which it is located. Most often, an increase in lymph nodes is associated with any infections. In addition, such a pathology occurs against the background of a tumor lesion.
So, let's take a closer look at why and under what diseases there is an increase in lymph nodes in children and adults:
- Purulent processes. As a rule, with such a deviation, the so-called acute lymphadenitis occurs. Most often this occurs as a result of microbes entering from wounds that are located in the area where one or another peripheral organ is located. The main symptoms of this inflammation include the appearance of pain on palpation and redness of the skin. If at such a moment the resulting bump is not opened, the shell of the node will tear, and the pus will penetrate into the tissues surrounding it, resulting in a rather serious complication called phlegmon.
- Enlarged lymph nodes in children often indicate the presence of tuberculosis. Typically, with suchdisease, bumps form in the chest cavity and on the neck.
- Often the cause of swollen lymph nodes in young children is the microbe Bartonella. The carriers of such a bacterium are cats, whose scratches can be observed quite often in a child. It is through these wounds that the microbe spreads very quickly through the lymphatic vessels and enters the nodes, which subsequently increase and become quite painful. Thus, a purulent wound that does not heal for a long time, as well as a bump that appears nearby, should always suggest the development of a “cat scratch” disease.
- With ARVI in adults and children, there can be up to several groups of enlarged lymph nodes. The reason for this deviation is an excessive response of the immune system to the invasion of any viruses into the patient's body. It should be noted that the lymph nodes in such situations do not increase very much, but when palpated, they are quite painful.
- Venereal diseases, in particular syphilis, also cause enlarged lymph nodes. In this case, the patient can observe bumps in the inguinal region, as well as sores on the genitals. Unlike other diseases with syphilis, enlarged lymph nodes can be painless, and therefore invisible to humans.
- Long-lasting enlarged groups of lymph nodes may indicate the presence of serious diseases such as listeriosis, brucellosis, HIV infection or mononucleosis.
Increased nodes in tumors
Swelling nodes canarise due to lymphoproliferative diseases (if the tumor originally originated from a lymph node), as well as from a metastatic lesion. The first deviation, first of all, includes lymphosarcoma and lymphogranulomatosis. Lymph nodes in such diseases increase to four to five centimeters and become quite dense. However, when palpated, the resulting bumps are not painful. By the way, with an initial increase in intra-abdominal or intra-thoracic lymph nodes, such diseases may not be recognized.
Summarize
Now you know what lymph nodes are. It should be especially noted that an increase in the organs of the peripheral system should immediately alert the patient. The reason for this is simple: such a pathological condition indicates that processes dangerous to life and he alth are taking place in the human body. In this case, it is recommended to immediately consult a doctor and undergo a complete medical examination.
