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.
How does the study of fossils strengthen the theory of evolution? The study of fossils reveals ancient and extinct species having many same structures to others of the present
what is mean by fisson
What are the characteristic of Soil It is commonly conceived as a plane at right angles to the surface. The upper part of a soil profile above the parent material in which proc
Write short note onApplications of apical dominance in horticulture and agriculture
What are the cell types that form the phloem? What are the main features of those cells? The major cells that form the phloem are the sieve elements and the companion cells. Th
What is genotype? What is the difference between phenotype and genotype? The Genotype is the genes, DNA nucleotide sequences contained in the chromosomes of an individual, whic
How is energy transferred along a food chain? The energy flux beside a food chain is always unidirectional, from the producers to the decomposers.
A complete gut is sometimes called tube within a tube. Why?
All the water used in the home that goes into the drain or into sewage collection system is called waste water. Domestic sewage is the waste water from kitchens, bathrooms etc. It
Define Requirements of Carbohydrates during Surgery? Carbohydrates: Carbohydrates are needed to build up glycogen stores and spare the proteins for tissue synthesis, Around GO%
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