NationMaster - Encyclopedia: Umbilical cord

In placental mammals, the umbilical cord is a tube that connects a developing embryo or fetus to the placenta. It normally contains three vessels, two arteries (Umbilical artery) and one vein (Umbilical vein), buried within Wharton's jelly, for the exchange of nutrient- and oxygen-rich blood between the embryo and placenta. The presence of only two vessels in the cord is sometimes related to abnormalities in the fetus, but may occur without accompanying abnormalities. Image File history File links Unbalanced_scales. ... Shortcut: WP:NPOVD Articles that have been linked to this page are the subject of an NPOV dispute (NPOV stands for Neutral Point Of View; see below). ... Image File history File links Size of this preview: 767 Ã— 600 pixel Image in higher resolution (854 Ã— 668 pixel, file size: 449 KB, MIME type: image/jpeg) This is a picture of our daughters umbilical cord stump seven days after birth. ... Image File history File links Size of this preview: 509 Ã— 600 pixelsFull resolution (891 Ã— 1050 pixel, file size: 185 KB, MIME type: image/jpeg) File historyClick on a date/time to view the file as it appeared at that time. ... For other uses, see Latin (disambiguation). ... Elseviers logo. ... Subclasses & Infraclasses Subclass â€ Allotheria* Subclass Prototheria Subclass Theria Infraclass â€ Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the presence of sweat glands, including those that produce milk, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex... For other uses, see Embryo (disambiguation). ... For other uses, see Fetus (disambiguation). ... The placenta is an ephemeral (temporary) organ present in female placental vertebrates, such as some mammals and sharks during gestation (pregnancy). ... f you all The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... Umbilical arteries carry deoxygenated blood from the fetus to the placenta in the umbilical cord. ... Fetal circulation; the umbilical vein is the large, red vessel at the far left The umbilical vein is a blood vessel present during fetal development that carries oxygenated blood from the placenta to the growing fetus. ... Whartons jelly is a gelatinous substance within the umbilical cord. ... A nutrient is either a chemical element or compound used in an organisms metabolism or physiology. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... The placenta is an ephemeral (temporary) organ present in female placental vertebrates, such as some mammals and sharks during gestation (pregnancy). ...

Shortly after birth, upon exposure to temperature change, the gelatinous Wharton's Jelly substance undergoes a physiological change that collapses previous structure boundaries and in effect creates a natural clamp on the umbilical cord which halts placental blood return to the neonate, causing the cord to cease pulsation. Though generally occurring as soon as 5 minutes after human birth, if the neonate's cord is submerged in warm water (i.e., a birthing pool) the cord may continue pulsing an additional time, up to 15-20 minutes. General obstetric practice introduces artificial clamping as early as 1 minute after birth of the neonate, a routine protocol questioned by some parents and care providers.

Explanation

The umbilical cord develops from the same sperm and egg from which the placenta and fetus develop, and contains remnants of the yolk sac and allantois. In humans, the umbilical cord in a full term neonate is usually about 50 centimetres (19.7 in) long and about 2 centimetres (0.75 in) diameter, shrinking rapidly in diameter in the after birth. The yolk sac is the first element seen in the gestational sac during pregnancy, usually at 5 weeks gestation. ... Allantois is a part of a developing animal embryo. ... A human infant The word Infant derives from the Latin in-fans, meaning unable to speak. ... A centimetre (American spelling centimeter, symbol cm) is a unit of length that is equal to one hundredth of a metre, the current SI base unit of length. ... An inch (plural: inches; symbol or abbreviation: in or, sometimes, â€³ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ...

In the third stage of labour, after the child is born, the uterus spontaneously expels the neonate's placenta along with the cord from the mother's body, 10–45 minutes after the birth. However, the umbilical cord is generally clamped during or within minutes of birth and severed shortly after, a practice of "active management of labor" which has become increasingly controversial due to the lower transfer of placental blood to the neonate and associated stressors. Childbirth (also called labour, birth, partus or parturition) is the culmination of a human pregnancy with the emergence of a newborn infant from its mothers uterus. ...

The health benefits of non-clamping of the cord and delayed umbilical severance are receiving attention in medical journals.^[1]^[2]^[3]

Today there are umbilical cord clamps which combine the cord clamps with the knife. These clamps are safer and faster, allowing one to first apply the cord clamp and then cut the umbilical cord. After the cord is clamped and cut (Western obstetrical protocol) the newborn wears a plastic clip on the navel area until the compressed region of the cord has dried and sealed sufficiently. The remaining umbilical stub remains for up to 2–3 weeks as it dries and then falls off. In nonseverance scenarios, also called lotus birth, the umbilical cord is wrapped up to within an inch of the newborn's belly, and the entire intact cord is allowed to dry like a sinew, which then falls off.^[4] This article does not cite any references or sources. ... Lotus Birth is the practice of leaving the umbilical cord unclamped, nor tied, after the third stage of labour so that the baby is left attached to its placenta until the cord naturally separates at the umbilicus, generally 1â€“3 days after birth (as compared to approximately 5 to 15...

Makeup and composition

The umbilical cord is made of Wharton's jelly, not ordinary skin and connective tissue. There are no nerves, so cutting it is not painful, but it is very strong, like thick sinew, and requires a sharp instrument if it is to be cut. Provided that umbilical severance occurs after the cord has stopped pulsing (5-20 minutes after birth), there is ordinarily no significant loss of either infant or maternal blood while cutting the cord. The cord contains two arteries which carry deoxygenated blood (from the fetus back to the mother) and one vein that carries oxygenated blood (from the mother to the fetus).

Historical commentary

“Another thing very injurious to the child, is the tying and cutting of the navel string too soon; which should always be left till the child has not only repeatedly breathed but till all pulsation in the cord ceases. As otherwise the child is much weaker than it ought to be, a portion of the blood being left in the placenta, which ought to have been in the child.”

Cord blood

Provided that the cord is not clamped for the first 5 minutes after birth, and kept level with the newborn, it allows baby to receive many maternal antibodies, critical stem cells, hormones, and vitamin K and provides the neonate with one-third to one-half of its entire blood volume. Download high resolution version (1200x1025, 934 KB)Newborn with suctioning and umbilical cord Taken 1:08 a. ... Download high resolution version (1200x1025, 934 KB)Newborn with suctioning and umbilical cord Taken 1:08 a. ...

Loss of this volume of blood through harvesting for blood banking can be the equivalent of subjecting an infant to a massive hemorrhage. This cord blood is a rich source of primitive, undifferentiated stem cells (i.e. CD34-positive and CD38-negative) which assist in neonatal adaptation. A cord blood bank is in the business of cord blood harvesting, and is NASDAQ listed. These companies promote very early cord clamping and cutting, to freeze for long-term cryo-storage at a cord blood bank should the child ever require the cord blood stem cells for rare diseases (for example, to replace bone marrow destroyed when treating leukemia). This practice is controversial: the RCOG (Royal College of Obstetricians and Gynaecologists, Great Britain) in its 2006 opinion states, "There is still insufficient evidence to recommend directed commercial cord blood collection and stem-cell storage in low-risk families." Child health advocates criticize the aggressive marketing campaigns of blood banks to pregnant parents-to-be as misleading, and assert that early cord blood withdrawal may actually increase the likelihood of childhood disease. Embryonic stem cells differentiate into cells in various body organs. ... Mouse embryonic stem cells with fluorescent marker. ... CD34 is a cluster of differentiation molecule present on certain cells within the human body. ... CD38 (cluster of differentiation 38) is a glycoprotein found on the surface of many immune cells (white blood cells), including CD4+, CD8+, B and natural killer cells. ... A cord blood bank is a place that stores umbilical cord blood for future use. ... A cord blood bank is a place that stores umbilical cord blood for future use. ... This article does not cite any references or sources. ... Leukemia or leukaemia (Greek leukos, â€œwhiteâ€; haima, â€œbloodâ€) (see spelling differences) is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). ...

For-profit cord blood banks receive from 80 ml to 180 ml of blood on the average amount of blood taken for CBC (cord blood collection). 'Banking' cord blood involves immediate, very early cord clamping to take a significant amount of blood (100mL on average) from the newborn at a crucial neonatal time. The amount of blood taken from the newborn child by early cord clamping can be understood by the fact that a 9 pound baby only creates 10 ounces of blood (300 ml). Therefore 180 ml is actually more than half this baby's blood supply and taking half of one's blood supply will weaken any child, or any adult that loses blood.

The cord banking business markets the use of CBEs as a mechanism that would eliminate the ethical difficulties associated with embryonic stem cells, however cord blood harvesting itself is fraught with ethical difficulties. (ESCs).^[5] Mouse embryonic stem cells. ...

The American Academy of Pediatrics 2007 Policy Statement on Cord Blood Banking title states that:

"Physicians should be aware of the unsubstantiated claims of private cord blood banks made to future parents that promise to insure infants or family members against serious illnesses in the future by use of the stem cells contained in cord blood;"

"Cord blood collection should not be performed in complicated deliveries. The cord blood stem cell–collection program should not alter routine practice for the timing of umbilical cord clamping;" and

"Private storage of cord blood as "biological insurance" should be discouraged, and that cord blood banks should comply with national accreditation standards developed by the Foundation for the Accreditation of Cellular Therapy (FACT), the US Food and Drug Administration (FDA), the Federal Trade Commission, and similar state agencies."

Problems

A number of abnormalities can affect the umbilical cord, which can cause problems that affect both mother and child:

A Nuchal cord (sometimes also referred to as a Nuchal loop) occurs when the umbilical cord of a fetus becomes wrapped around a part of the fetus, usually the neck. ... Cord prolapse, depicted by W.Smellie, 1792 Cord prolapse is an obstetric emergency during pregnancy or labour that endangers the life of the baby. ... Vasa previa is a rare condition in which fetal intramembranous blood vessels traverse the fetal membranes across the lower segment of the uterus between the fetus and the cervical opening. ... Image File history File links Download high resolution version (1616x952, 1089 KB) Summary Umbical cord clamp used 1993. ... Image File history File links Download high resolution version (1616x952, 1089 KB) Summary Umbical cord clamp used 1993. ...

Animals

In other mammals, the mother animal generally will gnaw the cord off separating the placenta from the baby. It is often consumed by the mother which nourishes her, and reduces tissue that would attract scavengers or predators. In chimpanzees, the mother focuses no attention on umbilical severance, instead staying still and nursing and holding her baby (with cord, placenta, and all) until the cord dries and separates within a day of birth, at which time she leaves the cord and placenta on the forest floor where it is recycled by scavengers. This was first documented by zoologists in the wild in 1974.^{[citation needed]} Species Pan troglodytes Pan paniscus Chimpanzees, also called chimps, are the common name for two species in the genus Pan. ...

Other uses for the term "umbilical cord"

The term "umbilical cord" or just "umbilical" has also come to be used for other cords with similar functions, such as the hose connecting a surface-supplied diver to his surface supply of air and/or heating, or a space-suited astronaut to his spacecraft. Surface supplied diver at the Monterey Bay Aquarium, Monterey, California Surface supplied diving refers to divers using equipment supplied with breathing gas using an umbilical cord from the surface, often from a diving support vessel but possibly, indirectly via a diving bell. ... Space suit from Apollo 11 moonwalk A space suit is a complex system of garments, equipment and environmental systems designed to keep a person alive and comfortable in the harsh environment of outer space. ... Astronaut Bruce McCandless II using a manned maneuvering unit outside the U.S. Space Shuttle Challenger in 1984. ...

The phrase "cutting the umbilical cord" is used symbolically to describe a child's breaking away from the parental home.

Additional images

References

^ Hohmann M. (1985). "Early or late cord clamping? A question of optimal time" (Article in German). Wiener Klinische Wochenschrift, 97(11):497-500. PMID 4013344.
^ Mercer J.S., B.R. Vohr, M.M. McGrath, J.F. Padbury, M. Wallach, W. Oh (2006). "Delayed cord clamping in very preterm infants reduces the incidence of intraventricular hemorrhage and late-onset sepsis: a randomized, controlled trial." Pediatrics, 117(4):1235-42. PMID 16585320.
^ Hutton E.K., E.S. Hassan (2007). "Late vs early clamping of the umbilical cord in full-term neonates: systematic review and meta-analysis of controlled trials." Journal of the American Medical Association, 297(11):1257-58. PMID 17374818.
^ Crowther S (2006). "Lotus birth: leaving the cord alone." The Practising Midwife, 9(6):12-14. PMID 16830839.
^ "Cord blood yields 'ethical' embryonic stem cells.", Coghlin A. New Scientist, August 18, 2005. Accessed June 25, 2007.

JAMA, published continuously since in 1883, is an international peer-reviewed general medical journal published 48 times per year. ... New Scientist is a weekly international science magazine covering recent developments in science and technology for a general English-speaking audience. ... is the 230th day of the year (231st in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 176th day of the year (177th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ...

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Categories: NPOV disputes | All articles with unsourced statements | Articles with unsourced statements since February 2007 | Cloning | Developmental biology | Embryology The placenta is an ephemeral (temporary) organ present in female placental vertebrates, such as some mammals and sharks during gestation (pregnancy). ... Decidua is the term for the uterine lining (endometrium) during a pregnancy. ... Before the fertilized ovum reaches the uterus, the mucous membrane of the body of the uterus undergoes important changes and is then known as the decidua. ... Chorionic villi are villi that sprout from the chorion, in order to give a maximum area of contact with the maternal blood. ... The trophoblast proliferates rapidly and forms a network of branching processes which cover the entire ovum and invade and destroy the maternal tissues and open into the maternal bloodvessels, with the result that the spaces in the trophoblastic network are filled with maternal blood; these spaces communicate freely with one... The gestational sac is the only available intrauterine structure that can be used to determine if an intrauterine pregnancy (IUP) exists, until the embryo is identified. ... For the alien race in Stephen Donaldsons The Gap Cycle, see Amnion (Gap Cycle). ... A drawing of the amniotic sac from Grays Anatomy. ... amniotic sac The amniotic sac is a tough but thin transparent pair of membranes, which hold a developing embryo (and later fetus) until shortly before birth. ... For the entertainment company see Chorion (company) The chorion surrounds the embryo and other membranes. ... An Introduction to Histogenesis Histogenesis is defined as the formation of tissues and organs from undifferentiated cells (Encarta Dictionary). ... Organogenesis is a stage of animal development where the ectoderm, endoderm, and mesoderm are formed. ... The vertebrate limb arises out of a general morphogenetic area called a limb field. ... In embryology, the limb bud is a structure formed by the developing limb, derived from lateral plate mesoderm[citation needed]. It is intimately related with the apical ectodermal ridge, which secretes factors inducing the initial differentiation of the limb bud. ... The Apical Ectodermal Ridge (AER) is a critical component in vertebrate limb development. ...

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