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

Epidemiology, Epidemiology:   The study of disease in populations.  In...

Epidemiology:   The study of disease in populations.  Includes: The Aetiology of the disease Patterns of distribution of the disease How the disease spread

Duck virus hepatitis, Duck virus hepatitis This highly contagious disea...

Duck virus hepatitis This highly contagious disease of ducks is caused by a member virus belonging to genus Enterovirus of the family Picornaviridae. It mostly affects duckling

How to measure post repair prv/iv pressure, How to measure Post Repair Prv/...

How to measure Post Repair Prv/iv Pressure ? In the operating room, after coining of1 bypass and before removing cannulae the RV and LV pressures are measured. The pressures ar

Trout beck zone - lotic ecosystem, Trout beck zone - Lotic Ecosystem T...

Trout beck zone - Lotic Ecosystem This is larger and more constant than the head stream. The greater volume of torrential water carves channels into exposed rock floor (bed ro

What are yeast, Q. What are yeast? Yeasts are unicellular fungi, which ...

Q. What are yeast? Yeasts are unicellular fungi, which are widely distributed in nature. They are somewhat larger than bacteria. The cell length is about 10μm and the diameter

The halstead-reitan neuropsychological battery, The halstead-reitan neurops...

The halstead-reitan neuropsychological battery The beginnings of the battery can be traced to the special laboratory established by Halstead in 1935 for the study of neurosurgi

How the foams are formed, How the foams are formed? Formation  of a foa...

How the foams are formed? Formation  of a foam is dependent on a foaming agent in the continuous phase prior to dispersion of gas.  The foaming agent must be adsorbed at the su

Bioenergetics, Energy Cycle  of Living Being Source of energy :All  mat...

Energy Cycle  of Living Being Source of energy :All  matter  locks  energy in the  from of   bonds  between component  molecules and   atoms. This  energy is the chemical  ener

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