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

Absorption, Absorption The monosaccharides, amino acids and other prod...

Absorption The monosaccharides, amino acids and other products of digestion must be passed on to other tissues to be useful for the organism. The process by which the digested

Define about the eukaryotic cell, The eukaryotic cell The eukaryotic ce...

The eukaryotic cell The eukaryotic cell is a complex unit and contains many structural features not seen in in the simple prokaryotic cell. Fig below shows the details of vario

Define triglycerides, Q. Define Triglycerides? Triglycerides are produc...

Q. Define Triglycerides? Triglycerides are produced by the esterification of glycerol with three fatty acid molecules. They are the body's major energy store, particularly in a

Differance between pulsus bigerniny or trigeminy presence, Differance betwe...

Differance between pulsus bigerniny or trigeminy and presence of bruit ? Pulsus bigerniny or trigeminy: After every 2nd or 3rd beat respectively there will be a longer inter

Do enzymes act better under acid or basic ph, Do enzymes act better under a...

Do enzymes act better under acid or basic pH? Most enzymes act in pH among 6 and 8, a range that corresponds to the general acidic level of cells and blood. There are enzymes,

List four common exercises you will recommend to a patient, List four commo...

List four common exercises you will recommend to a patient. Common exercises are: - brisk walking - cycling - swimming - playing tennis - dancing - rope skip

Adapting to health changes in the older adult, You are soon to be registere...

You are soon to be registered as a nurse and have applied to work in a unit where you will be caring for a diverse range of clients with medical and surgical complexities. You know

Describe how the hypothalamus regulates, Describe how the hypothalamus regu...

Describe how the hypothalamus regulates the secretion of anterior pituitary hormones and identify all of the individual hypothalamic regulatory factors. Describe how the hypothalam

Can pathophysiology causes cardiovascular disease, Q. Can Pathophysiology c...

Q. Can Pathophysiology causes cardiovascular disease? Cigarette use activates platelets, increases circulating fibrinogen, increases heart rate, and elevates blood pressure. It

Explain about the chytridiomycota - fungi, Explain about the Chytridiomycot...

Explain about the Chytridiomycota - Fungi Chytridiomycota - Look at the Figure, which illustrates chytridiomycota. These are the simplest among true fungi and are commonly call

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