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

What is mitral valve and coronary arteries, Q. What is Mitral Valve and Cor...

Q. What is Mitral Valve and Coronary Arteries? On the PA view, mitral valve calcification is seen just to the left of the spine, below the position of the aortic valve. The lar

Explain the regulation of blood glucose concentration, Explain the Regulati...

Explain the Regulation of Blood Glucose Concentration? A number of mechanisms function to maintain blood glucose at remarkably constant level of 70-100 mg/dl under fasting cond

Set up of phototherapy unit, Set Up of Phototherapy Unit Phototherapy ...

Set Up of Phototherapy Unit Phototherapy generally consists of four to eight cool white, day bright, or special blue fluroescent tube lights covered by a plastic shield and p

Describes the tenants of pangenesis theory, Which of the following best des...

Which of the following best describes the tenants of Pangenesis Theory? A. The hereditary material is composed in every organ/tissue and is transmitted to the next generation b

What is bidirectional glenn without cardio pulmonary bypass, What is Bidire...

What is Bidirectional Glenn (BDG) without Cardio Pulmonary Bypass Surgical approach is through median sternotomy. If there is only a single superior vena cava some surgeons pre

Why is maternal milk important for the immune protection, Why is maternal m...

Why is maternal milk important for the immune protection of the baby? Besides being nutritionally significant, maternal milk participates in the defense of the baby against inf

Pulse, PULSE Pulse frequency and heart rate are identical i.e. 72. ...

PULSE Pulse frequency and heart rate are identical i.e. 72. It can be felt in superficial arteries as in wrist (radial artery [thumb] and ulner artery of brachial art.),

Seed dispersal, what are the characteristics of the stages in seed dispersa...

what are the characteristics of the stages in seed dispersal

Alcohol related emergencies, Alcohol Related Emergencies: Alcohol is o...

Alcohol Related Emergencies: Alcohol is one of  the most serious health problems. Alcoholism is defined as a primary or chronic disease with genetic, psychological and environ

How can the immune memory lead to the efficacy of vaccines, Q. How can the ...

Q. How can the immune memory lead to the efficacy of vaccines and also produce allergies? Vaccines are controlled inoculations of fragments of inactive infectious agents or of

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