The chyliferous vessel is a structure found within the intestinal villi, whose function is to absorb the product of food digestion, that is, the chyle that reaches the intestinal mucosa.
It can be said that chyliferous vessels are the continuation of lymphatic drainage, but with the exception that within the intestinal mucosa the lymph acquires other characteristics. That is why chyliferous vessels are considered modified lymphatic vessels, useful for transporting a milder type of lymph that is rich in lipids. This substance is known as chyle, since it is transformed into chylomicrons to finally reach the blood.
Quiliferous vessel Source: File: Gray1059.png / en.m.wikipedia.org / wiki / File: Gray1059.png
Chylomicron is made up mainly of fat (triglycerides, cholesterol and phospholipids) covered by a protein layer. Fat gives it that whitish or milky appearance, hence the name of chyliferous for the vessels that absorb it.
The term glass comes from the Latin vasum, which means container to hold liquids. And the word quiliferous comes from the combination of two words. In the first place from the Greek term khylos which means juice and secondly from the Latin word ferre, which means to carry or transport.
These vessels are of great importance because chylomicrons are large molecules and therefore cannot cross the endothelium of the blood capillaries of the intestinal villi, as other nutrients do.
History
The quiliferous vessels were discovered by Gaspar Aselli (1581-1626) using the corpses of dogs. This Italian doctor wrote that these vessels were observable only when the animal was in the process of digestion before being slaughtered, otherwise it was not possible to evidence them.
Later, Pierre Gassendi (1592-1655) gave evidence of the existence of chyliferous vessels, but believed that they were blood vessels that for some reason contained chyle.
Two centuries later, Frank Starling (1866-1927) recognized lymphatic vessels as structures other than blood vessels. And in the twentieth century Rusznyak, Földi and Szado in 1960 discovered what the trajectory of lymph in the body is like.
Histology
Lymph is an ultrafiltrate of the blood that is transported by the lymphatic vessels. These have the ability to collect everything that the blood capillaries cannot absorb, but the lymph that originates in the small intestine is high in fat, which is why it changes its name to chyle.
That is why the lymphatic vessels at the level of the intestinal villi are called chyliferous vessels, because the material they transport has become chyle.
In this sense, it can then be said that the chyliferous vessels are modified lymphatic vessels. These initially are as thin as a blind bottom capillary, but later they expand their thickness in order to collect everything that the capillaries cannot absorb.
Chyle is a mixture of pancreatic juice, bile and lipids (triglycerides, cholesterol and phospholipids) product of the digestion of foods rich in fat.
If a cross section of the villi is made, the chyliferous vessels can be observed. At the microscopic level, the discontinuity of the lining of the chyliferous vessels is evident.
Location
The chyliferous vessel is located in the folds of the small intestine, specifically in the central area of each villus at the level of the lamina propria. It covers the entire path of the villi from the tip to its base.
The chyliferous vessel, before reaching the submucosa, originates capillary branches. As they pass through the submucosa, they become lymphatic vessels of a significant caliber.
It should be noted that chyliferous vessels, unlike lymphatic vessels, do not have valves that regulate the passage of lymph.
Function
The villi of the intestinal mucosa are structures that are rich in capillary vessels, as these are necessary to absorb nutrients (carbohydrates, amino acids) and carry them to the blood. However, lipids follow another path, being these transported by the lymph through the lymphatic system. Therefore, the chyliferous vessel is associated with this great system.
The chyliferous vessel, as its name indicates, is responsible for absorbing lipids transformed into chylomicrons at the intestinal level. Once collected, they are passed to the large thoracic duct to later be poured into the blood.
On the other hand, it is important to note that chylomicrons are large molecules, since they are a mixture of emulsified fat surrounded by proteins. This condition prevents it from being absorbed by the blood capillaries located in the intestinal villi. In order for chylomicrons to be absorbed by the chyliferous vessels, they must be equal to or less than 0.5 mm.
The transport of chylomicrons through the chyliferous vessels occurs as follows:
Intestinal villi are highly motile structures. Movement is caused by mechanical stimuli, such as the presence of chyme and by the secretion of the hormone villicinin.
The aforementioned stimuli make it possible to contract smooth muscles, called Brücke's muscle or motor muscle of the villi. The number of contractions is six times for each minute elapsed.
With each contraction, the villi reduces in size by half. This causes the material inside the chyliferous vessel to reach the base more quickly.
Research
Some investigators have conducted experiments with mice lacking vascular endothelial growth factor 1 and NRP1 protein.
They observed that the mice could eat a high-fat diet and not gain weight. Apparently, the lack of these two elements inhibits the function of the chyliferous vessels. Unabsorbed fat is removed.
On the other hand, Ilha et al. In 2004 observed important lesions in the intestinal mucosa in two dogs that presented severe diarrhea, anorexia, vomiting, lethargy, progressive decrease in body weight and respiratory problems.
The dogs were diagnosed with intestinal cholangiectasia with lipogranulomatous lymphangitis.
Histologically, they observed a mucosa with a very pale appearance, where the villi were elongated white, the mesenteric lymphatic vessels were distended with calcareous areas and there was also accentuated ectasia in the chyliferous vessels.
References
- Medical dictionary. Chiliferous vessel. Navarro University Clinic. Available at: cun.es/dictionary-médico.
- «Cisterna del chilo» Wikipedia, The free encyclopedia. 3 Aug 2019, 23:21 UTC. 15 Dec 2019, 13:45
- Narváez-Sánchez R, Chuaire L, Sánchez M, Bonilla J. Intestinal circulation: Its organization, control and role in the critical patient. Colomb Med 2004; 35 (4): 231-244. Available at: scielo.org.co/
- Olmos Martínez S, Gavidia Catalán V. The lymphatic system: the great forgotten of the circulatory system Eureka Magazine on Teaching and Disclosure of Sciences, 2014; 11 (2): 181-197. Available at: redalyc.org/
- Soler C. Intra-abdominal pressure and sepsis. Rev cubana med. 2001; 40 (1): 45-49. Available at: scielo.org
- Ilha R, Loretti A, Barros C. Intestinal lymphangiectasia and lipogranulomatous lymphangite in two canines. Rural Science, 2004; 34 (4), 1155-1161. Available em: dx.doi.org