Third week - embryonic development, Biology

Assignment Help:

Third Week - Embryonic Development

Throughout the third week of development the ICM separates from the uophoblast and forms the flattened embryonic disc, which at first consists of cells of all three germ layers, ectoderm, endoderm and mesoderm and is termed as the epiblast. From this a lower layer separates to form the endoderm. The second layer, mesoderm, forms through the migration of cells through the primitive streak that forms as the embryonic disc elongates. The cells remaining in the upper layer make the ectoderm. These three germ layers will give rise to all the organs of the body as pointed out in Figure.

2006_Third Week.png

Figure: The organs of the body form from the three germ layers

The embryo's heart as well begins its development as a pair of microscopic tubes. The cardiovascular system is the first system to become functional in the embryo. At the end of the 3rd week the heart tubes fuse and become linked to the blood vessels in the embryo, body stalk, chorion and yolk sac, to make a primitive blood circulatory system. Chorionic villi (that will form the placenta later) also begin to form during this period.


Related Discussions:- Third week - embryonic development

What is enhancers , While  various  positive  control  components  li...

While  various  positive  control  components  lie  close  to the  gene  they  regulate additional can be situated long distances away (sometimes 10-50 kb) either upstream or downs

protraction from hiv , Protraction from HIV  Under the following condi...

Protraction from HIV  Under the following conditions HIV is not transmitted 1) The secretions and body fluids like Saliva, Tears, Sweat, Faeces, and Urine have negligible HIV c

Which areas of the globe is gymnosperm abundance noteworthy, Q. In which ar...

Q. In which areas of the globe is gymnosperm abundance noteworthy? These plants are the typical vegetation of cold regions like the boreal forest or taiga of the northern hemis

Metabolism of carbohydrates, Carbohydrates form the major bulk of human die...

Carbohydrates form the major bulk of human diet and are also the chief sources of energy. Carbohydrates are easily digested and broken down by enzyme action into glucose and are ea

How to investigate mitral stenosis by electrocardiogram, Q. How to Investig...

Q. How to Investigate mitral stenosis by Electrocardiogram? Electrocardiographic changes are not specific for mitral stenosis and are never diagnostic for any valvular heart di

Integumentary, What modern technology used for the integumentary system?

What modern technology used for the integumentary system?

Cladogram help, Recent molecular analyses indicate that the artiodactyls, w...

Recent molecular analyses indicate that the artiodactyls, which include hippos and camels, are paraphyletic, whereas cetaceans are monophyletic and cetaceans and hippos form a clad

Explain disadvantage of colonies at different dilution, Explain the Disadva...

Explain the Disadvantages of Colonies Obtained At Different Dilution 1. Heat sensitive microorganisms may be damaged by melted agar, giving low viable count as compared to spre

What is the phenomenon called as red tide, Q. What is the phenomenon called...

Q. What is the phenomenon called as "red tide"? Which ambiental harms can it cause? Red tide is a phenomenon that takes place when dinoflagellates algae from the pyrrophyte gro

Explain unacceptable aesthetics, Unacceptable Aesthetics The implant wh...

Unacceptable Aesthetics The implant which has successfully integrated with bone may still be a failure if the Prosthesis which it is designed to support does not meet with the

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