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

Functions of synergids, Functions of Synergids Ultra structurally the ...

Functions of Synergids Ultra structurally the structure and concentration of cell organelles reveals that synergids are metabolically active. The following Wee functions are a

Estimation of protein by miscellaneous parameters include, Estimation of pr...

Estimation of protein by Miscellaneous parameters include? Miscellaneous parameters include Plasma amino acid levels Microbiological methods Chemical scoring

Explain about the nutrition security, Explain about the Nutrition Security?...

Explain about the Nutrition Security? Food security is a part of the broader concept of nutrition security. A household can be said to be nutritionally secure if it is able to

Ammonotelism - excretion, Normal 0 false false false EN...

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

Explain the biochemical approach in taxonomy, Explain the Biochemical Appro...

Explain the Biochemical Approach in Taxonomy Comparative biochemistry is being used increasingly in the systematic of animals, both for identification of organisms as well as f

What is the heterotrophic hypothesis on the origin of life, What is the het...

What is the heterotrophic hypothesis on the origin of life? As per to the heterotrophic hypothesis the first living beings were very simple heterotrophic organisms that is not

Why is the krebs cycle also called the final common pathway, Why is the Kre...

Why is the Krebs cycle also called the final common pathway of the degradation of organic compounds? The Krebs cycle is known as the final common pathway of the degradation of

Horse diseases-equine infectious anaemia, Equine infectious anaemia Eq...

Equine infectious anaemia Equine infectious anemia (EIA), an acute or chronic viral disease of the equines, shows intermittent fever, loss of weight, depression, progressive w

Calculate the minimum dissolved oxygen tension, Given our knowledge so far ...

Given our knowledge so far we now need to evaluate if it is feasible to run the process in the designed vessel. We therefore need to compare the oxygen uptake rate and the oxygen t

Chlorine (cl) - micronutrients, Chlorine (Cl) - Micronutrients The rol...

Chlorine (Cl) - Micronutrients The role of Cl - in plant is not clearly understood. Cl - is required in Hill reaction, the water splitting reaction of photosystem II. In 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