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

Invertebrates, Are chaetopterus species coelomate?

Are chaetopterus species coelomate?

Explain preparation and properties of modified starches, Preparation and pr...

Preparation and properties of modified starches Improved performance of starches may  be realized by physical and chemical modifications. The major physically modified starch i

AMOEBA, mORPHOLOGY OF AMOEBA AND ITS ADAPTATIONS

mORPHOLOGY OF AMOEBA AND ITS ADAPTATIONS

Automated dna sequencing, Automated DNA sequencing is now common place whic...

Automated DNA sequencing is now common place which is based on the chain termination method but using a fluorescent dye attached to an oligonucleotide primer instead of using radio

Describe the working of ploidy reduction, Q. During which meiosis division ...

Q. During which meiosis division does ploidy reduction take place? And Does it ploidy reduction occur in mitosis? In the cell division by meiosis ploidy reduction occurs in mei

Relate the oxide layer and biocompatibility of titanium, Q. Relate the oxid...

Q. Relate the oxide layer and biocompatibility of titanium? The compatibility of a metal with its host environment depends on its resistance to biodegradation and on the degree

Explain about the pregnancy and obesity, Explain the Pregnancy and Obesity?...

Explain the Pregnancy and Obesity? Obesity is associated with increased risk for gestational diabetes, hypertension, pre- eclampsia, perinatal mortality and the need for induce

Potassium sparing diuretics, The potassium-sparing agents spironolactone, t...

The potassium-sparing agents spironolactone, triamterene, and amiloride are often useful in combination with the loop diuretics and thiazides. Triamterene and amiloride act on the

Classification of freshwater ecosystems, Classification of Freshwater Ecosy...

Classification of Freshwater Ecosystems Fresh water ecosystems depend on the terrestrial ecosystems for large quantities of organic and inorganic matter which are constantly a

What carbohydrates does a plant make from glucose, (a) What carbohydrates d...

(a) What carbohydrates does a plant make from glucose? (b) Which of these carbohydrates is transported round the plant? (c) Which carbohydrate is the main s

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