Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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.
Q. Which are the subproducts of the photochemical phase that are essential for the chemical stage of photosynthesis? The chemical stage of photosynthesis depends on ATP and NAD
How does the addition of a watery secretion to the contents of the gut help in the process of digestion?
What is commensalism? Commensalism is the ecological interaction in which one individual advantage while the other is neither benefited nor harmed. Commensalism is a harmonious
Q. Explain Shannon-Wiener index? This diversity measure is based on information theory of measure of order (or disorder) within a particular system. For our uses, this order co
entamoeba histolyca and Giardia lambia were isolated
what are the origin, morphology, active constituents, uses and market preparation of tanco beans ?
What is the Mendel's first law? The Mendel's first law postulates that a characteristic (trait) of an individual is always verified by two factors, one inherited from the fathe
Alterations occuring in cereal & cereal products, legumes You are already aware of the chemical composition of cereals and pulses. We will now look into changes occurring in t
Q. What is the function of the immune system? The immune system performs specific defense against agents the antigens that are harmful to the body or foreign. Exogenous anti
Requirement and Recommended Dietary Allowance (RDA) for Vitamin A? Recommendations for adequate vitamin A intake based on the amounts needed to correct night blindness among vi
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd