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

Germ line gene therapy, Germ line gene therapy - This approach either targ...

Germ line gene therapy - This approach either targets to correct the totipotent cells within human conceptus or stimulate the genetic modifications within reproductive cells that

Compound Microscope, The highest possible magnification that can obtain whe...

The highest possible magnification that can obtain when using using a microscope?

Define the meaning of goitrogens, Define the Meaning of Goitrogens? Goi...

Define the Meaning of Goitrogens? Goitrogens are substances that interfere with iodide metabolism in any way that inhibits thyroid hormone synthesis. As a result, there is augm

What do you mean by post-herbal period, What do you mean by Post-Herbal Per...

What do you mean by Post-Herbal Period ? Ans. It is difficult to draw a sharp line of demarcation between the transition period, marked by various attempts of classificati

Metamorphosis in amphibians, Metamorphosis in Amphibians Metamorphosi...

Metamorphosis in Amphibians Metamorphosis is radical in anurans, slight or not exists in urodeles. In anuran amphibians like toads and most frogs, metamorphosis is generally

What is life threatening haemorrhage, What is Life threatening haemorrhage ...

What is Life threatening haemorrhage Life threatening haemorrhage has been reported when a drill perforates the sublingual region of the mandible and injures the sublingual arte

Explain the eating disorder not otherwise specified (ednos), Explain the Ea...

Explain the Eating Disorder Not Otherwise Specified (EDNOS)? Earlier, we emphasized that a diagnostic category for eating disorders that fail to meet full criteria for anorexia

What is cardiac catheterization, Q. What is Cardiac Catheterization? Ro...

Q. What is Cardiac Catheterization? Routine cardiac catheterization is not necessary in patients with mitral regurgitation. It may be done when there is discrepancy between cli

How many grams of sodium dodecyl sulfate, How many grams of sodium dodecyl ...

How many grams of sodium dodecyl sulfate (mw = 288.37) would you dissolve in 80 mLs of water to make a 20% solution of SDS?

Fisson, what is mean by fisson

what is mean by fisson

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