Extra-embryonic membranes and placenta, Biology

Assignment Help:

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.


Related Discussions:- Extra-embryonic membranes and placenta

Glycogenolysis, Glycogenolysis:   It is breakdown  of glycogen to glucose  ...

Glycogenolysis:   It is breakdown  of glycogen to glucose  by means  of the   reaction   series  shown  in figure 6.11 Like glycogenesis  it also  occurs in all  body  cells , But

What is mucic acid test and its principle, What is Mucic Acid Test and its ...

What is Mucic Acid Test and its principle? This is a specific test for galactose and is given by galactose as well as lactose, which is made up of galactose and glucose. Pr

How are the main classes of arthropods classified, How are the main classes...

How are the main classes of arthropods classified according to the presence of larval stage in their embryonic development? In crustaceans there are species with direct and oth

Animal reproduction, Animal Reproduction - Reproduction is the ability ...

Animal Reproduction - Reproduction is the ability to produce new organism of its own type. It is meant to increase their number. Reproduction includes - (i) Replication o

Carpentier-technique of operation, Carpentier: Edwards or similar annul...

Carpentier: Edwards or similar annuloplasty ring is then sutured into place by interrupted sutures to support the repair and reduce the annulus to a measured amount. The ring m

Dietetic foods for diabetes, Dietetic Foods for diabetes: With advances...

Dietetic Foods for diabetes: With advances in food technology, foods for special use by diabetics are now available in the global market, they are emerging in India also. These

Explain the properties of gum arabic, Properties Gum Arabic is unique b...

Properties Gum Arabic is unique between the natural hydrocolloids because of its extremely high solubility in water and can yield solutions of up to 55% concentrations. Solutio

Biology Project, what does the future look like with trash in the ocean?

what does the future look like with trash in the ocean?

Leukamia.., is the leukamia dangerous

is the leukamia dangerous

What is taxonomic diversity, Q. What is Taxonomic diversity? Taxonomic ...

Q. What is Taxonomic diversity? Taxonomic diversity is relative abundance of a species as well as the ancestor descendant relationships of species to each other. For example, a

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd