villus

(noun)

a small projection from a mucous membrane, particularly those found in the intestines

Related Terms

Examples of villus in the following topics:

  • Absorption in the Small Intestine

    • Each villus has a network of capillaries and fine lymphatic vessels called lacteals close to its surface.

  • Prenatal Diagnostic Tests

    • An invasive method involves probes or needles being inserted into the uterus, e.g. amniocentesis (which can be done from about 14 weeks gestation up to about 20 weeks), and chorionic villus sampling (which can be done earlier: between 9.5 and 12.5 weeks gestation).
    • Chorionic villus sampling is associated with slightly more risky to the fetus.
    • However, since chorionic villus sampling is performed earlier in the pregnancy than amniocentesis, typically during the first trimester, it can reasonably be expected that there will be a higher rate of miscarriage after chorionic villus sampling than after amniocentesis.
    • Because of the risk of miscarriage and fetal damage associated with amniocentesis and chorionic villus sampling procedures, many women prefer to first undergo screening so they can find out if the fetus' risk of birth defects is high enough to justify the risks of invasive testing.

  • Histology of the Small Intestine

    • Intestinal villi (singular: villus) are tiny, finger-like projections that protrude from the epithelial lining of the mucosa .
    • Each villus is approximately 0.5-1.6 mm in length and has many microvilli (singular: microvillus), each of which are much smaller than a single villus.

  • Fetal Circulation

    • Oxygen then diffuses from the placenta to the chorionic villus, an alveolus-like structure, from which it is carried to the umbilical vein.

  • Histology of the Large Intestine

    • During each mitosis, one of the two daughter cells remains in the crypt as a stem cell, while the other differentiates and migrates up the side of the crypt and eventually into the villus.

  • Digestive System: Small and Large Intestines

    • The apical surface of each villus has many microscopic projections: the microvilli.

  • Down Syndrome

    • Genetic counseling along with genetic testing, such as amniocentesis, chorionic villus sampling (CVS), or percutaneous umbilical cord blood sampling can be offered to families who may have an increased chance of having a child with Down syndrome, or where normal prenatal exams indicate possible problems.