chorionic villi

Examples of chorionic villi in the following topics:

• Chorionic Villi and Placental Development

  • In the placenta, chorionic villi develop to maximize surface-area contact with the maternal blood for nutrient and gas exchange.
  • Chorionic villi sprout from the chorion after their rapid proliferation in order to give a maximum area of contact with the maternal blood.
  • During the primary stage (the end of fourth week), the chorionic villi are small, nonvascular, and contain only the trophoblast.
  • Chorionic villi are vital in pregnancy from a histomorphologic perspective and are, by definition, products of conception.
  • Image illustrating the placenta and chorionic villi.

• Implantation

  • The syncytiotrophoblast then implants the blastocyst into the endometrium of the uterus by forming finger-like projections into the uterine wall called chorionic villi.
  • The chorionic villi grow outwards until they come into contact with the maternal blood supply.
  • The chorionic villi will be the border between maternal and fetal blood during the pregnancy, and the location of gas and nutrient exchange between the fetus and the mother.
  • The creation of chorionic villi is assisted by hydrolytic enzymes that erode the uterine epithelium.
  • During implantation, extensions of the trophoblast, the syncytiotrophoblasts, embed within the endometrium and form chorionic villi.

• Development of the Extraembryonic Coelom

  • It is the fetal aspect of the placenta that gives rise to chorionic villi.
  • Villi emerge from the chorion, which invade the endometrium, destroy the uterine decidua, and allow the transfer of nutrients from maternal blood to fetal blood.
  • Chorionic villi are at first small and nonvascular, and consist of only trophoblast, but they increase in size and branch.
  • Blood is carried to the villi by the paired umbilical arteries, which branch into chorionic arteries and enter the chorionic villi as cotyledon arteries.
  • Until about the end of the second month of pregnancy, the villi cover the entire chorion, and are almost uniform in size; but, after this stage, they develop unequally.

• Fourth Week of Development

  • The chorion undergoes rapid proliferation and forms numerous processes.
  • The chorionic villi, which invade and destroy the uterine decidua and at the same time absorb from it nutritive materials for the growth of the embryo.
  • Until about the end of the second month of pregnancy the villi cover the entire chorion, and are almost uniform in size, but after this they develop unequally.

• The TORCH Panel of Tests

  • They are a group of viral, bacterial, and protozoan infections that gain access to the fetal bloodstream through the placenta via the chorionic villi.

• Trophoblast Development

  • Cytotrophoblast in the tips of villi can differentiate into another type of trophoblast called the extravillous trophoblast.

• Anatomy of the Small Intestine

  • The epithelial cells which line these villi possess even larger numbers of microvilli.
  • The villi in the jejunum are much longer than in the duodenum or ileum.
  • The wall itself is made up of folds, each of which has many tiny finger-like projections known as villi on its surface.
  • The villi contain large numbers of capillaries that take the amino acids and glucose produced by digestion to the hepatic portal vein and the liver.
  • Lacteals are the small lymph vessels that are present in villi.

• Histology of the Small Intestine

  • The intestinal villi are part of the mucosa.
  • Intestinal villi (singular: villus) are tiny, finger-like projections that protrude from the epithelial lining of the mucosa.
  • Villi increase the internal surface area of the intestinal walls.
  • An increased absorptive area is useful because digested nutrients (including sugars and amino acids) pass into the villi, which is semi-permeable, through diffusion, which is effective only at short distances.
  • The villi are connected to blood vessels that carry the nutrients away in the circulating blood.

• Characteristics of Amniotes

  • However, the eggs of amniotes contain three additional extra-embryonic membranes: the chorion, amnion, and allantois.
  • While the inner amniotic membrane surrounds the embryo itself, the chorion surrounds the embryo and yolk sac.
  • The chorion facilitates exchange of oxygen and carbon dioxide between the embryo and the egg's external environment.
  • The key features of an amniotic egg are the chorion, amnion, and allantois.

• Absorption in the Small Intestine

  • From the plicae circulares project microscopic finger-like pieces of tissue called villi (Latin for "shaggy hair") .
  • The function of the plicae circulares, the villi and the microvilli is to increase the amount of surface area available for the absorption of nutrients.
  • The epithelial cells of the villi transport nutrients from the lumen of the intestine into these capillaries (amino acids and carbohydrates) and lacteals (lipids).