United States or São Tomé and Príncipe ? Vote for the TOP Country of the Week !
These little fingers for drinking up the food are scarcely one fourth as large as the point of a pencil. They are called villi. The villi are filled with blood tubes having thin walls. The food passes through these walls into the blood stream. Much of it then goes to the liver, but the fatty parts flow up a tube along the backbone and empty into a blood tube in the neck.
Proliferative changes in the synovial membrane are attended with increased vascularity and thickening of the membrane and an enlargement of its villi and fringes.
But they afterwards disappear from one part of the surface, and grow proportionately thicker on the other part. The former has only a few small villi or none at all; the latter is thickly covered with large and well-developed villi; this alone now constitutes the placenta. This discoplacenta lies on one side of the chorion.
The villi are structures especially adapted to the work of absorption, and they are found only in the small intestine. The mucous membrane in all parts of the canal, however, is capable of taking up some of the digested materials. Villi. 2. Small glands, called crypts. Small artery. 2. Lacteal. 3. Villus showing termination of the lacteal. 4. Villus showing capillaries. 5.
The villi of the chorion push their branches into the blood-filled tissues of the coat of the uterus, and the vessels of each loop together so intimately that it is no longer possible to separate the foetal from the maternal placenta; they form henceforth a compact and apparently simple placenta.
That we do not know all about the interchange of substances between mother and child must be admitted; but the essential facts, and they alone are of interest here, have been established beyond contention. There is no doubt whatever that the mother's blood surrounds the placental villi but never enters the child.
There is no real coalescence of the two placentas at any part of the surface of contact. Hence at birth the foetal placenta alone comes away; the uterine placenta is not torn away with it. The formation of the placenta is very different in the second and higher section of the Placentals, the Deciduata. Here again the whole surface of the chorion is thickly covered with the villi in the beginning.
As the partition in the villi between the maternal blood-vessels and those of the foetus is extremely thin, there is a direct exchange of fluid between the two, and this is of the greatest importance in the nutrition of the young mammal. It is true that the maternal vessels do not entirely pass into the foetal vessels, so that the two kinds of blood are simply mixed.
Villi, or in English, Wilis, are the spirits of affianced damsels, whose lovers have proved untrue. They rise from the earth at midnight, and assemble upon the highway attired in all their bridal finery. From midnight until dawn they wheel their wild dances and watch for their faithless lovers.
In the alimentary canal are certain pointed eminences called villi, and certain ridges called valvuloe conniventes. The makers of heating apparatus have exactly reproduced the first in the "pot" of their furnaces, and the second in many of the radiators to be seen in our public buildings. The object in the body and the heating apparatus is the same; to increase the extent of surface.
Word Of The Day