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

Define translation phase of gene expression process, Define Translation Pha...

Define Translation Phase of gene expression process? The NDA which the transcript into m RNA is translated into protein with the help of ribosomes, m RNA, amino acids, a number

How muscle contraction intensely increased, To increase the strength of the...

To increase the strength of the muscle work is the muscle contraction intensely increased? An increase in the strength of the muscle work is not achieved by enhance in the inte

How does the inflammation mechanism work, How does the inflammation mechani...

How does the inflammation mechanism work? When some tissue injury happens histamine and other vasoactive substances (known as mediators of inflammation) are released, they caus

What are the main divisions and representing species, What are the main div...

What are the main divisions and representing species of the gymnosperms? This group of plants can be divided into conifers (pine, sequoia, cypress), that have flowers known as

Define iron factors affecting absorption of dietary iron, Define Iron Facto...

Define Iron Factors affecting absorption of dietary iron? We have read earlier that iron in foods occurs either as haem or non-haem iron. Haem iron comprises of iron in combina

Enzymatic mutation detection method, This technique utilizes an enzyme reso...

This technique utilizes an enzyme resolvase, endo vii, cloned from the bacteriophage t4. This enzyme has high specificity to find deletions, insertions, and base substitutions muta

Define briefly about the seed proteins, Define briefly about the Seed Prote...

Define briefly about the Seed Proteins? Although a large number of plants produce seeds having protein contents in excess of 15%, only a few are utilized for food, eg. soybean,

Blood flow during exercise - circulation, Normal 0 false fals...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Cinemicrography, Cinemicrography Earlier it was impossible to follow the ...

Cinemicrography Earlier it was impossible to follow the evenvts within the cell due to: i) non-visibility of cell organelles under a light microscope, ii) maintenance of cells

Energy, what are the types of pyramids studied

what are the types of pyramids studied

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