Gate of the Lymph Node

The hilum of the lymph node is where the lymphatic vessels leave the lymph nodes and connect with the lymphatic vessels of other areas. This is an important anatomical element that plays a key role in the functioning of the lymphatic system.

The lymph node hilum is located on the surface of the lymph node, usually on its posterior wall. They are a narrow opening between two layers of tissue that surround a lymph node. Through this opening, lymphatic vessels and nerves enter and exit the lymph node.

The lymphatic vessels leaving the portal of the lymph node are called lymphatic sinuses. They carry lymph, containing immune cells and other components of the immune system, to the main lymphatic vessel. Lymphatic sinuses are a network of small channels that distribute lymph throughout the body.

In addition, at the gate of the lymph node there are nerve fibers that provide sensitivity and innervation to the lymph node. Also at the gates of the lymph nodes there are lymphatic capillaries, which are the initial elements of the lymphatic drainage system and ensure the exchange of fluid between blood and lymph.

Thus, the lymph node gate plays an important role in the functioning of the immune system and the lymphatic system in general. They provide communication between the lymph nodes and other tissues of the body, and also provide sensitivity to the lymph node and its innervation.

Gate of the lymph node

* **The gate of the lymph node** is the widest place of the lymphatic vessel or the lymphatic system as a whole

Lymphocytes

Lymph flow and lymph drainage Lymph flow is the movement of lymph in the body, and lymph drainage is the movement of lymph from the body through one or more lymph nodes. Normally, lymphatic drainage prevails over lymphatic flow and is centrifugal (remote) in nature [14, 50]. An important condition for the existence of the lymphatic microsystem is gravity, which stimulates active lymphatic drainage in the direction of the venous part of the vascular bed [51]. Without continuous active lymphatic drainage, filtration of tissue fluid through the epithelium of lymphatic capillaries is impossible.

In clinical practice, the amount of lymph flow is determined by the radionuclide method, based on the study of the content of radioactive isotopes of elements in the body. The maximum level of radioisotope content in venous blood is observed 20-60 minutes after its ingestion. Having reached the lymphatic bed, it is partially absorbed into its lumen and then diffuses through all elements of the lymphatic network: arterioles, intercellular spaces, sinuses of lymphatic vessels, cells of the medulla of lymph nodes, trabeculae, furrows of the last row and then enters the bloodstream to measure radioactivity [53 ]. Normally, the amount of blood should increase at a rate of about 0.07-0.2 mm/min [54], which is quite consistent with the speed of lymph flow and is a criterion for its norm. No matter how high the number of lymphangions even of the main lymphatic capillary, its total volume per hour is approximately 0.15-0.3 ml/min. This means that the speed of lymph flow does not exceed the volume of lymph formation, resulting in its pressure [55]. Simultaneously with the increase in blood flow, there is a decrease in lymph formation, which normally amounts to 5% of the blood circulation volume [56].

Lymphatic valves play an important role in regulating the direction of lymphatic fluid flow. They ensure continuity of lymph circulation, filling the capacity of the lymphatic channel and determining the amount of lymph pressure. As a result of their action, an increased pulse wave is transmitted to the lymph flow when