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

Explain the cladosporium - fungi and yeast, Explain the Cladosporium - Fung...

Explain the Cladosporium - Fungi and Yeast? Classification Kingdom - Mycetae Division - Amastigomycota Form - Class - Deauteromycetes Form - Order - Moniliales F

Male accessory sex organs, Normal 0 false false false E...

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

Use of alternate metabolic pathways, Use of Alternate Metabolic Pathways ...

Use of Alternate Metabolic Pathways Plants surviving under water-logged conditions offer the simplest example of such a response. The submerged parts of such plants use the an

Excreatory organ, what is the excreatory organ of silverfish?

what is the excreatory organ of silverfish?

Radiography, R a d i o g r a p h y: ...

R a d i o g r a p h y: Radiograph or X-ray remains the most well-known and primary diagnostic tool of all the imaging modalities. It works b

Osmotic and ionic regulation, Osmotic and Ionic Regulation The  ammono...

Osmotic and Ionic Regulation The  ammonotelism, ureotelism and uricotelism are the adaptations of the animals for the removal of toxic nitrogenous wastes and thereby maintain

Vesicular stomatitis, Vesicular stomatitis Vesicular sto matitis virus ...

Vesicular stomatitis Vesicular sto matitis virus be longs to the ge nus Vesiculovirus in fa mily Rhabdoviridae. The disease clinically resembles foot-and-mouth disease, but is

Denaturing gel, Denaturing Gel is an agarose or the acrylamide gel run und...

Denaturing Gel is an agarose or the acrylamide gel run under conditions which destroy the secondary or tertiary protein or RNA. For protein, this generally means the inclusion of

Sub xyphoid pericardial window -types of surgery, Sub Xyphoid Pericardial W...

Sub Xyphoid Pericardial Window :  It could be done under local or general anaesthesia. A small vertical midline incision is made over the xyphoid process on to the linea alba

How a volcanic eruption removes all plant life, A volcanic eruption removes...

A volcanic eruption removes all plant life from a valley below the volcano Explain why succession following the eruption is likely to happen more quickly on the valley floor than o

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