Placenta The umbilical cord

Placenta The umbilical cord - Placenta The umbilical cord...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Placenta The umbilical cord The umbilical cord develops from and contains remnants of the yolk sac and allantois (and is therefore derived from the same zygote as the foetus). It forms by the fifth week of foetal development, replacing the yolk sac as the source of nutrients for the foetus. The cord is not directly connected to the mother's circulatory system, but instead joins the placenta, which transfers materials to and from the mother's blood without allowing direct mixing. The umbilical cord in a full term neonate is usually about 50 centimetres (20 in) long and about 2 centimetres (0.75 in) diameter. This diameter decreases rapidly within the placenta. The umbilical cord is composed of Wharton's jelly, a gelatinous substance made largely from mucopolysaccharides. It contains one vein, which carries oxygenated, nutrient-rich blood to the foetus and two arteries that carry deoxygenated, nutrient depleted blood away. Occasionally, only two vessels (one vein and one artery) are present in the umbilical cord.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 4

Placenta The umbilical cord - Placenta The umbilical cord...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online