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

Hetero trophic mode of nutrition, what is heterotroophic mode of nutrition?...

what is heterotroophic mode of nutrition?give some information about heterotrophic mode of nutrition?

Explain hormonal proteins, Explain Hormonal proteins Hormonal proteins ...

Explain Hormonal proteins Hormonal proteins coordinate the bodily activities. Various peptide and protein hormones (such as insulin and growth hormone) carry information tha

Light microscopy, Light microscopy: Microscopy started with light micr...

Light microscopy: Microscopy started with light microscopes using visible light to illuminate the objects, the most used and familiar microscope is called compound light micro

What is the inactivation of the x chromosome, What is the inactivation of t...

What is the inactivation of the X chromosome? What is a Barr body? Inactivation of the X chromosome is a phenomenon that happens in women. As women have two X chromosomes only

Explain the absence of passive fit of the prosthesis, Absence of Passive Fi...

Absence of Passive Fit of the Prosthesis A passive fit of the prosthesis reduces long term stresses in the superstructure, implant components and the bone adjacent to the impla

Correction of reversible causes, In the long term reversible causes of hear...

In the long term reversible causes of heart failure like valvular lesions, myocardial ischemia, uncontrolled hypertension, arrhythmias, alcohol, negative inotropic agents, intracar

Carbon dioxide in the atmosphere, Which part of the carbon cycle is respons...

Which part of the carbon cycle is responsible for the enhancing concentration of carbon dioxide in the atmosphere. The burning of fossilized products (coal and oil) of some pla

Sterilization of apparatus for microbiology experiments, Sterilization of A...

Sterilization of Apparatus for Microbiology Experiments : Containers of dangerous biological materials and the doors leading to laboratories or rooms in which work with pathogenic

Why dna ligase is needed to complete the replication, Which of the followin...

Which of the following best defines the reason why DNA ligase is needed to complete the replication of internal chromosomal segments? A. DNA ligase is able to delete the last n

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