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

For the biological diversity is mitosis or meiosis, For the biological dive...

For the biological diversity is mitosis or meiosis the more important process? Meiosis is the cell division process that permits the formation of gametes to sexual reproduction

How do chordates reproduce, Q. How do chordates reproduce? Reproduction...

Q. How do chordates reproduce? Reproduction in beings of the phylum Chordata is sexual, with the exception of urochordates that can be also reproduce asexually. In some classes

Causes of mitral regurgitation, Q. Causes of Mitral Regurgitation? Mitr...

Q. Causes of Mitral Regurgitation? Mitral regurgitation is the most common valvular abnormality seen in clinical practice. Different disease processes leading to mitral regurgi

Explain spoilage of sweetened condensed milk, Q. Explain Spoilage of Sweete...

Q. Explain Spoilage of Sweetened condensed milk? The sweetened condensed milk contains about 8% milk fat, 23% total milk solids and sweetened with the addition of a sweetener,

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

Dietary management during myocardial infarction, Dietary management during ...

Dietary management during Myocardial Infarction? Patients who suffer from an attack of myocardial infarction are hospitalized and are usually kept under strict medical supervis

Define the term - cholera, Define the term - Cholera Cholera is caused...

Define the term - Cholera Cholera is caused by the gram negative,  V. cholerae, which is acquired by ingesting food or water contaminated  by faecal material from patients or

Explain pulmonary capillary wedge pressure, Q. Explain Pulmonary Capillary ...

Q. Explain Pulmonary Capillary Wedge Pressure? The PCW waveform is similar to LA pressure waveform except that it is damped and delayed due to transmission through the lungs. T

Invertebrete zoology, give an example invertebrate phylum/phyla for protopl...

give an example invertebrate phylum/phyla for protoplasmic grade organization

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