umbilical chord

Question 1

describe umbilical cord

Answer 1

Lifeline between the fetus and placenta

Dimensions:
* Length:About50cm(at term)
* Diameter:2cm

Structure: Mesodermal connective tissue (Wharton’s jelly) which is resistant to twisting and compression

Contents: (A) One umbilical vein (B) two umbilical arteries and (C) Remnants of the yolk sac and the allantois

Functions: To protect the vessels that travel between the fetus and the placenta throughout pregnancy

Question 2

describe Development of umbilical cord (2nd-5th week)

Answer 2

1.TWO STALKS are seen at the beginning of development
1. A ventral one, the yolk sac stalk, containing the vitelline duct
and the vitelline vessels
2. A caudal one, the connecting stalk, containing the allantois and
the umbilical vessels
3. The connecting stalk progresses ventrally as a result of the
cephalocaudal flexion of the embryo and fuses with the yolk sac stalk to form the umbilical cord
2.THE UMBILICAL CORD brings together, in the same mesenchymal core, the components of the connecting stalk (the allantois and umbilical vessels) and the vitelline duct and vessels
3.THE UMBILICAL CORD is covered by amnion which is continuous with the outer epithelial layer of the embryo at the attachment of the umbilicus

Question 3

Primitive umbilical ring

Answer 3

A connecting stalk within which passes the allantois, two umbilical arteries and one vein.
* The vitelline duct (yolk sac stalk)
* A canal which connects the intra- and extra
embryonic coelomic cavities
* By the 10th week: The gastrointestinal tract has developed & protrudes through the umbilical ring to form a physiologically normal herniation into the umbilical cord (retract by the end of the third month)

Question 4

Fate of umbilical cord

Answer 4

After delivery of placenta, the umbilical cord is usually clamped and severed.
* The site of its attachment leaves a scar, the navel (belly button) on the anterior wall of the abdomen

Question 5

Anomalies of umbilical cord

Answer 5

A. Omphalocele
B. Abnormal length of umbilical cord
C. Vasa previa
D. Umbilical cord knots

Question 6

Omphalocele

Answer 6

Condition caused by failure of returning of intestine or other abdominal viscera back into the abdominal cavity through the umbilical opening
Abdominal contents are covered with a transparent sac

Question 7

Abnormal length of umbilical cord

Answer 7

Extremely long umbilical cord: Umbilical cord around neck, false/true knots, cord compression
Extremely short umbilical cord: Difficult delivery of placenta, early separation of placenta

Question 8

Vasa previa

Answer 8

Fetal blood vessels run closely to the inner cervical os below the presenting part, without the support of placental tissue or umbilical cord.
 Fetal blood vessels course within the membranes are at risk of rupture when the supporting membranes rupture.
 Result in sudden blood loss and drop in blood pressure of the baby.

Question 9

Umbilical cord knots

Answer 9

 Looping or interweaving of the umbilical cord that occurs during intrauterine growth of a fetus.
 True knot is present when the umbilical cord loops upon itself and can be manually released / untied.
 Pseudo knot (false knot) is merely a varicosity or redundancy of an umbilical vessel (usually the vein) within the cord substance and cannot be physically released in an intact cord.