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

The denver development screening test (ddst), THE DENVER DEVELOPMENT SCREEN...

THE DENVER DEVELOPMENT SCREENING TEST (DDST) The Denver Development Screening Test is a standardized test to assess gross motor, fine motor, language and social development

Vertebrates, characterstics and classification of vertebrates

characterstics and classification of vertebrates

Evaluate the texture of various foods, Q. Evaluate the texture of various f...

Q. Evaluate the texture of various foods? A number of instruments are available to evaluate the texture of various foods. Brief discussions on these instruments follow. Cons

Zoology, living and non living

living and non living

Explain micronutrient deficiencies during kwashiorkor, Explain Micronutrien...

Explain Micronutrient deficiencies during kwashiorkor? Almost all the children manifest anaemia (due to iron deficiency) of some degree. Eye signs of vitamin A' deficiency are

Neurophysics Assignment Help, What is Neurophysics Neurophysics is the ...

What is Neurophysics Neurophysics is the field of biophysics dealing with nervous system. Neurophysics covers a extensive spectrum of phenomena from molecular & cellular mechan

What is xaxim, What is xaxim? Most pteridophytes have subterraneous ste...

What is xaxim? Most pteridophytes have subterraneous stems parallel to the substrate known as rhizomes. Xaxim is a type of pteridophyte with an aerial stem generally perpendicu

Light harvesting in green plants, Sunlight is absorbed by chlorophyll molec...

Sunlight is absorbed by chlorophyll molecules.  Chlorophyll is a porphyrin in that nitrogen atoms are coordinated to a magnesium ion instance for it is a magnesium porphyrin.  This

Insulin, INSULIN Linear polymer of b-D-Glucose. Insulin is small-...

INSULIN Linear polymer of b-D-Glucose. Insulin is small-sized (25 - 35 residues) fructosan homopolysaccharide which is a reserve carbohydrate present in roots, tubers and

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