Extra-embryonic membranes and placenta, Biology

Extra-Embryonic Membranes and Placenta

The extra embryonic membranes like you already know provide nourishment and protection. These membranes are fundamentally similar to the extra-embryonic membranes of reptiles and birds, however the method of origin differs in humans. During the third and fourth week, the amnion grows around the embryo enclosing it in a membranous fluid filled sac in which the growing embryo and later the foetus floats and can move freely. This sac as mentioned in the previous section is a shock absorber and encloses a fluid, the amniotic fluid, that helps to keep the temperature of foetal environment stable. Another membrane, the chorion develops from the trophoblast cells. The chorion is a extremely specialised extraembryonic tissue. It facilitates the transfer of gases, nutrients and wastes among the embryo and the mother. It is the primary part of the placenta that we will study a little later. Yolk sac develops during the second week of development even though there is no yolk in the human egg. It does not give nourishment to the embryo but it becomes surrounded by mesoderm that forms the blood cells till the liver of the embryo becomes functional in the sixth week. The yolk sac with the allantois forms the umbilical cord. Part of the yolk sac also forms the lining of the gut. The allantois that forms during the third week of development is a tiny sausage shaped pouch on the yolk sac. It also is accountable for producing blood cells and later develops into the umbilical blood vessels.

Posted Date: 2/1/2013 5:07:40 AM | Location : United States







Related Discussions:- Extra-embryonic membranes and placenta, Assignment Help, Ask Question on Extra-embryonic membranes and placenta, Get Answer, Expert's Help, Extra-embryonic membranes and placenta Discussions

Write discussion on Extra-embryonic membranes and placenta
Your posts are moderated
Related Questions
REPRODUCTIV E ISOLATION - According to the biological species concept, members of one species are reproductively isolated from members of all other species. Accordingly, re

Q Where in the cell can ribosomes be found? What is the major biological function of ribosomes? Ribosomes can be found free in the cytoplasm, adhered to the external side of th

Dietitians and nutritionists Dietitians and nutritionists, who are associated with hospitals and clinics generally have regular work hours. At times, they may be required to wo

Noncompetitive inhibition In  this  type  of  inhibition, the inhibitor binds at  a site  on  the  enzyme  other  than catalytic site. As there is no competition between the s

You ran both a body temperature and room temperature test for each enzyme you tested. Did the two temperatures seem to have an effect on the enzyme Exercise? Why or why not?

What functions of the smooth ER and rough ER are similar?

G e n e constructs Designing and cloning of the gene construct is the fundamental step in the generation of transgenic animals, essentially determining success or failure of

1. Define each term and give an example of an application that uses the following: a. Biocompatible material b. Biodegradable material c. Biomimetic

What are diseases of the connective tissue? What are some of them? Diseases of the connective tissue are hereditary or acquired diseases(lots of autoimmune cause) characterized

How are genetic diseases classified? The Genetic diseases classify into chromosomal abnormalities and genetic mutations. Between chromosomal abnormalities there are the aneu