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

Uses of microbes in industry-amino acids and vitamins, Normal 0 ...

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

Shrub stage - xerarch, Shrub Stage - Xerarch Sufficient soil is formed...

Shrub Stage - Xerarch Sufficient soil is formed in the herbs stage, for supporting the woody plants or the shrubs. They migrate with the help of seeds or rhizomes from the adj

What are the two main subdivisions of the phylum Chordata, Normal 0 ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4 What are the two mai

Characteristics of lake ecosystems, Characteristics of Lake Ecosystems ...

Characteristics of Lake Ecosystems The environment of static waters of lakes and ponds sharply contrasts with those of lotic ecosystems. Light penetration in lakes is usually

How bone implant interface can be evaluated, How bone implant interface can...

How bone implant interface can be evaluated 1) Evaluation of the bone - implant interface can be done by following: i) Implant mobility and discomfort a)  Clinical implan

Fossil history of horse, Evolution of Horse - Credit to Prof. C. Marsh...

Evolution of Horse - Credit to Prof. C. Marsh (1879) of Yale University for complete work.   S.No   Fo ssil/Genus   Period

How to use atp to make reactions go, What do enzymes do, and how? How is en...

What do enzymes do, and how? How is enzyme activity regulated in cells? How do ATPases u se ATP to make reactions go?

Diagnosis of acute myelogenous leukemia, The most recent blood work of a pa...

The most recent blood work of a patient with a diagnosis of acute myelogenous leukemia (AML) reveals thrombocytopenia. Where is the patient most likely to experience abnormal bleed

Availability of adp, Availability of ADP When  the ADP  levels increase...

Availability of ADP When  the ADP  levels increase due to hydrolysis ofATP  in various biosynthetic reactions,  the  rate of reaction to generate ATP  is accelerated and this i

Electrocardiography, ECG: Myocardial ischemia is indicated by T-wave invers...

ECG: Myocardial ischemia is indicated by T-wave inversions. Left ventricular hypertrophy (LVH) criteria: R in aVL >13 mm R voltage in L1+ S III >25 mm S v1 + R v5 or v6

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