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

Determine the quality of various food grains, Q. Determine the quality of v...

Q. Determine the quality of various food grains? After undertaking this activity, you will be able to: • determine the various fractions involved with the physical examinati

Tonicity and the plant cells., Potato type: Potato A: Beginning displaceme...

Potato type: Potato A: Beginning displacement (ml)= Ending displacement (ml) = Potato B: Beginning displacement (ml)= Ending displacement (ml) = Potato type: Potato A: Beginn

Define excretion of methyl malonic acid in urine, Define Excretion of Methy...

Define Excretion of Methyl malonic acid in urine (Methyl malonil aciduria)? Methyl malonic acid is found only in traces in normal urine (1-2 mg/day). In vitamin  B 12 deficie

Define the types of canned foods, Define the Types of Canned Foods? 1....

Define the Types of Canned Foods? 1. Some foods form convection currents when being heated inside a can and so are heated faster since self-mixing - as foods become more visco

What capacity does the brain have to repair itself, What capacity does the ...

What capacity does the brain have to repair itself after injury or disease? It has long been accepted dogma that central nervous system doesn't regenerate itself after traumati

Morphogenesis and totipotency, Morphogenesis and Totipotency A chlamy...

Morphogenesis and Totipotency A chlamydomonas mother cell gives rise to two daughter cells by a simple division. But a leaf cell cannot give rise to a new plant except in cas

Define the reduction of the activation energy, How does the formation of th...

How does the formation of the enzyme-substrate complex define the reduction of the activation energy of chemical reactions? The enzyme possibly works as a test tube within whic

Nucellus - ovule, Nucellus - Ovule Enclosed within the integuments li...

Nucellus - Ovule Enclosed within the integuments lies a homogenous mass of tissue which is termed as the nucellus. This is the tissue in which the female gametophyte differen

Solar energy input, Solar Energy Input We know that the spectral distri...

Solar Energy Input We know that the spectral distribution and the intensity of solar radiation incident on the earth's surface are known. Of the enormous'amount of energy that

Foot as burrowing organ, Foot as Burrowing Organ The Scaphopoda that ...

Foot as Burrowing Organ The Scaphopoda that usually have burrowing habit, possess foot suitably modified for burrowing purpose. The conical and protrusible foot of Dentalium

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