What Is the Right Lymphatic Duct?
Lymphatic vessels are divided into capillary lymphatic vessels, lymphatic vessels, lymphatic stems and lymphatic ducts, which are the closed channels for the return of lymph fluid to the blood circulation.
- Chinese name
- Lymphatic vessels
- Foreign name
- lymphatic vessels
- Solid
- Capillary lymphatics confluence
- Features
- Thin diameter and thin wall
- Lymphatic vessels are divided into capillary lymphatic vessels, lymphatic vessels, lymphatic stems and lymphatic ducts, which are the closed channels for the return of lymph fluid to the blood circulation.
Lymphatic capillaries
- Capillary lymphatic vessels are a network of ducts composed of a single layer of endothelial cells. They start with a slightly enlarged blind end in the interstitial space. They are more permeable than capillaries and can penetrate larger molecules in addition to tissue fluids. Substances, such as proteins, bacteria, foreign bodies, cancer cells, etc. After the interstitial fluid enters the capillary lymphatic vessels, it is called lymph fluid, which is a colorless and transparent fluid. The capillary lymphatics in the villi of the small intestine can absorb fat particles and make the lymphatic fluid milky white, so they are called chyle ducts. Except for the central nervous system, bone marrow, and some non-vascular structured organs (epithelium, cornea, lens, cartilage) lacking capillary lymphatic vessels, capillary lymphatic vessels are almost all over the body. Capillary lymph vessels kiss each other to form a network, which is close to the capillaries, but they are not connected to each other. Capillary lymphatic vessels are larger in diameter than capillaries, and they are very malleable, sometimes they can be enlarged more than three times.
Lymphatic lymph
- Lymphatic vessels are formed by the confluence of capillary lymphatic vessels, the diameter of which is thickened, and the structure of the tube wall is similar to that of the small veins. Its characteristics are: The tube wall is thin and there are many valves. The appearance of a valve is the main marker of capillary to lymphatic transition. The structure of the valve is similar to that of the venous valve, but it is large in number and has the effect of preventing lymphatic reflux. The valves of the lymphatic vessels of the extremities are well developed, with lower limbs more than upper limbs. The valve spacing varies from place to place, with an average of 2 to 3 mm in the proximal organs, 6 to 8 mm in general lymphatic vessels, 12 to 15 mm in the lymphatic trunk, and 6 to 10 mm in the thoracic ducts. The valve attachment area expands into a sinus shape, making the appearance of the lymphatic vessels beaded. During its centripetal stroke, the lymphatic vessels flow through at least one lymph node, and some pass through 8 to 10 lymph nodes. It has been reported that the lymphatic vessels of the heart, esophagus, thyroid, adrenal glands and other organs can be inserted into the thoracic duct without lymph node intervention. There are many communication branches between lymphatic vessels, more than veins. Except that there is a wide anastomosis between shallow and deep lymphatic vessels (bounded by deep fascia), between the lymphatic vessels on the left and right sides of the body Can also communicate with each other. It has the characteristics of age, the lumen of the embryonic and neonatal lymphatic vessels is wide, densely meshed, and there are many anastomoses. After 2 to 3 years of age, the lymphatic vessels gradually become thinner and the number decreases.
Collateral and collateral circulation
- There are many collateral branches between lymphatic vessels. Usually, their diameter is narrow or closed, and they do not participate in lymphatic reflux. However, when lymphatic reflux is blocked or interrupted, the related collateral branches gradually expand and open, delivering lymph fluid, and become the lymphatic side circulation. In addition, a new anastomotic branch of lymphatic vessels can occur at the site of lymphatic disruption, connecting the ends to restore lymphatic flow. The lymphatic side circulation is obstructed in the lymphatic flow, the lymphatic vessels are stretched, the valve fails, and the lymph flows concentrically into the vein through the side branches. Therefore, the paralymphatic side circulation becomes a path for the spread of lesions or cancer metastasis. Many factors can promote or delay the establishment of the lymphatic side circulation. Experiments have shown that warmth, exercise, and infection can promote the establishment of lateral paracirculation, while nerve injury, radiation exposure, and braking (still) can slow down the formation of lateral paracirculation.