umbilical cord (ŭmbĬl´Ĭkəl), cordlike structure about 22 in. (56 cm) long in the pregnant human female, extending from the abdominal wall of the fetus to the placenta. Its chief function is to carry nourishment and oxygen from the placenta to the fetus and return waste products to the placenta from the fetus. It consists of a continuation of the membrane covering the fetus and encloses a mucoid jelly through which one vein carries oxygenated blood and two arteries carry unoxygenated blood. After birth, the cord is clamped off and cut. It is sometimes abnormal in length and may break prematurely or form loops or knots, which may asphyxiate the fetus. The stump of the cord that is left attached to the infant withers and drops off, leaving the scar known as the navel.
Because umbilical cord blood is especially rich in stem cells (cells that give rise to red blood cells and lymphocytes) some parents choose to save it in private cord blood banks in case of future need as a transplant alternative to bone marrow, but in many diseases treated with stem cells such autologous transplants are contraindicated. Studies have shown that people not related to the donor (genetically mismatched) can benefit from transplants of umbilical cord blood in combating leukemia and other cancers. Cord blood has also been used to repair heart and other tissue defects in children with certain metabolic disorders.
"umbilical cord." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (February 23, 2019). https://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/umbilical-cord
"umbilical cord." The Columbia Encyclopedia, 6th ed.. . Retrieved February 23, 2019 from Encyclopedia.com: https://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/umbilical-cord
Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).
Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.
Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:
Modern Language Association
The Chicago Manual of Style
American Psychological Association
- Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
- In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.