BGDA Practical Placenta - Cord Development

From Embryology
BGDsmall.jpg
Practical 14: Implantation and Early Placentation | Villi Development | Maternal Decidua | Cord Development | Placental Functions | Diagnostic Techniques | Abnormalities


Placental/Umbilical Cord

The placental cord (umbilical cord) is the connecting region between the functional placenta and the embryo/fetal umbilical region. The human cord varies physically in overall length, increasing to about 60 to 70 cm at term, degree of coiling, number of vessels and insertion site on the placenta. This extraembryonic structure contains the placental blood vessels and allantois.

Normally a pair of placental arteries are wrapped around a single (left) placental vein. A persistent right umbilical vein is thought to be a rare anomaly.

Placental Arteries and Vein

Placental cord vessels 02.jpg Placental cord vessels 01.jpg Placental cord cross-section.jpg


Week 8

Stage 22 image 086.jpg Stage 22 image 090.jpg

Placental Cord Histology

Virtual Slide - Virtual Slides - Placenta Please note that there are additional slides listed in the current set, only the first placenta slide and the cord cross-section will be covered in detail in the practical class.

Placental Cord Ultrasound

Placental cord ultrasound 03.jpg

Ultrasound image of transverse scan through the cord show the method of estimation of the cross-sectional area.


Placental cord ultrasound 04.jpg

Wharton's Jelly

Placental cord cross-section
  • placental cord connective tissue (substantia gelatinea funiculi umbilicalis)
  • amorphous substance containing glycosaminoglycans, proteoglycans and hyaluronic acid.
  • cells similar to smooth muscle that allows a contractile function.
  • network of collagen that form canaliculi and perivascular spaces.
  • maintain blood flow to the fetus during placental cord compression during pregnancy or delivery.

First described and named after Thomas Wharton (1614–1673) an English physician and anatomist.


Hofbauer Cells

  • located the core of placental villi
  • macrophages with micropinocytotic activity and phagocytosis ability
  • possible paracrine role for early stages of placental vasculogenesis
  • express angiogenic growth factors (VEGF)

Fetal Circulation

Gray0502.jpg

Additional Information

Cord Length

The following are lengths and classifications at term.

  • Normal range - 50 to 60 cm.
  • Short cord - less than 35 cm.
  • Long cords - over 70 cm can be associated with wrapping around the fetus and other abnormalities.

Cord Coiling

  • Hypocoiling - associated with increased incidence of fetal demise, intrapartum fetal heart rate decelerations, operative delivery for fetal distress, anatomic-karyotypic abnormalities and chorio-amnionitis.
  • Hypercoiling - associated with increased incidence of fetal growth restriction, intrapartum fetal heart rate decelerations, vascular thrombosis and cord stenosis.



BGDsmall.jpg
Practical 14: Implantation and Early Placentation | Villi Development | Maternal Decidua | Cord Development | Placental Functions | Diagnostic Techniques | Abnormalities