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

Difference between self pollination and cross pollination, What is differen...

What is difference between self pollination and cross pollination? Which of the two modes of pollination contributes more to the plant diversity? Self pollination take places w

Imaginal discs, Imaginal Discs In the holometabolous larva, there are ...

Imaginal Discs In the holometabolous larva, there are two cell populations: (1) The larval cells that are used for the larval structures and (2) The imaginal disc and th

Define the dietary sources and chemical forms, Define the Dietary Sources a...

Define the Dietary Sources and Chemical Forms? Isoflavones and coumestans are the most common compounds. Soybeans and soyfoods are the most important sources, containing approx

Kingdoms , phlum,class,characteristics of chromalveolata

phlum,class,characteristics of chromalveolata

What is the vector of malaria, Q. What is the vector of malaria? How differ...

Q. What is the vector of malaria? How different is its behavior from the behavior of the vector of dengue fever? The vector of malaria is the mosquito of the genus Anopheles, a

Phylum Protozoa, Make a detailed study on Phylum Protozoa taking an example...

Make a detailed study on Phylum Protozoa taking an example with clear labeled diagrams.

What devices used for oxygen therapy, What Devices Used for Oxygen Therapy?...

What Devices Used for Oxygen Therapy? Variable performance systems: With these devices, the FiO 2 would vary depending on the patient's breathing pattern. In general, rapid, s

What is the production of rna called, What is the production of RNA called ...

What is the production of RNA called and what is the enzyme that catalyzes the process? The making of RNA from information included in DNA is called transcription. The enzyme t

Clinical manifestations of maple syrup urine disease, Q. Clinical manifesta...

Q. Clinical manifestations of maple syrup urine disease? Clinical manifestations are expressed upon protein loading or with febrile illness. In most severely impaired enzyme de

Define feeding options for premature and lbw babies, Define Feeding Options...

Define Feeding Options for Premature and LBW Babies? Different workers have tried different method and since all methods are successful, it is dependent on the individual infan

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