Implantation - pre-embryonic development, Biology

Assignment Help:

Implantation - Pre-Embryonic Development

After entering the uterus and formation of ICM, the blastocyst starts to embed in the endometrium of the uterine wall. By one week after fertilization the trophoblast secretes enzymes which digest the tissues and blood vessels of the uterine wall. The invading trophoblast differentiates into two layers, the outer syncytiotrophoblast and the inner cellular layer. Like the syncytiotrophoblast swallows more blood vessels in the uterine wall lacunae develop in the syncytiotrophoblast that get filled up with blood from the mother and exchange of gases takes place here. So a primitive utero- placental circulation is established. This nourishes the embryo till the placenta is made. By the 10th day the blastocyst is totally embedded in the uterine wall.

This kind of implantation in which the embryo gets fully embedded is termed as interstitial implantation. The trophoblast begins to secrete human chorionic gonadotropin (HCG). HCG causes the corpus luteum to be maintained and to carry on to secrete estrogen and progesterone. Sometimes implantation may occur outside the uterus at some other location. In that case it is an ectopic pregnancy. The implantation site might be the fallopian tube or even the abdominal cavity. In ectopic pregnancy the embryo has to be surgically removed as if it is not done, it can lead to tuba1 rupture, internal bleeding, shock and possible death. At the beginning of the second week a small cavity appears between the trophoblast and ICM. This is the amniotic cavity that will grow around the embryo and later the foetus, It is a fluid filled cavity that act as an insulator against shocks, cold and heat. At similar time the ICM also differentiates into two layers, the upper epiblast which provides rise to the embryo and the lower hypoblast which gives rise to the extraembryonic membranes.


Related Discussions:- Implantation - pre-embryonic development

Explain the psychological management of eating disorders, Explain the Psych...

Explain the Psychological Management of eating disorders? All anorexia nervosa or bulimia nervosa patients are resistant to any kind of therapy and hospitalization may be a lif

Explain phylum ascomycetes, Phylum Ascomycetes 1) Sexual reproduction i...

Phylum Ascomycetes 1) Sexual reproduction is by conjugation and is followed by the formation of ascospores inside a sac called ascus. 2) The asci may be grouped together to

Introduction to heart surgery, INTRODUCTION :  It took just hundred years ...

INTRODUCTION :  It took just hundred years for cardiac surgery to advance to what it is today. Before 1896, surgeons considered heart to be "inviolable" and it was stated that ope

Define some advantages of breast milk for infants, Define some Advantages o...

Define some Advantages of breast milk for Infants? 1) Breast milk is a simple and natural method of feeding. It is hygienic, inexpensive and available at all times at the righ

Steroid and thyroid hormones, Steroid and Thyroid Hormones Cytoplasmic...

Steroid and Thyroid Hormones Cytoplasmic receptors for steroids are proteins with two subunits that bind to the steroid molecules. When both receptor sites are occupied by the

What is gluconeogenesis, What is gluconeogenesis There is accumulation ...

What is gluconeogenesis There is accumulation of lactate, which is released into the blood and taken up by  the liver where  it  is converted to glucose by  the  process called

Determine when the homologous chromosomes occur, In which period of meiosis...

In which period of meiosis does the pairing of homologous chromosomes occur? The pairing of homologous chromosomes is an essential step for meiosis because the rightness of the

Explain why methionine is the first amino acid, Explain why methionine is t...

Explain why methionine is the first amino acid in every growing polypeptide. The tRNA that pairs with the start codon on mRNA carries methionine. RNA having ribose; DNA contain

Draw a graph for an iv multiple infusion of a drug, Draw A graph for an IV ...

Draw A graph for an IV multiple infusion of a drug, and label on the graph where the trough (predose) blood draw would be collected and where the peak (postdose) blood draw would b

Which compounds results from cyclization of glucose, Which of the following...

Which of the following compounds results from cyclization of glucose? Select one: a. alpha-D-glucopyronose b. beta-D-glucopyronose c. alpha-D-glucofuranose d. beta-D

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