Cleavage and blastocyst, Biology

Cleavage and Blastocyst

Even though the cleavage is complete and all the blastomeres are of more or less equivalent size. Synchronization of mitoses in the blastomeres is lost very early. Even the first two blastomeres may cleave at dissimilar rates; consequently, a 3 cell stage and subsequently stages of five, six, seven blastomeres and so forth are found. The result of the cleavage is a solid mass of cells a morula, where some cells are superficial and others lie inside, completely cut off from the surface through them enveloping cells.

In due course the superficial cells join to make a distinct epithelial layer. This layer provides rise to most of the extra embryonic parts (the embryonic membranes), serves to attach the embryo to the uterine wall, and mediates in the supply of nourishment to the embryo from the maternal body via the placenta. This outer layer of the mammalian embryo is termed as the trophoblast (the term trophe meaning nourishment). The cells lying in the interior are known as the inner cell mass (ICM), and it is these cells that provide material for the formation of the embryo proper. Hence they may, be referred to as the formative cells. Sooner or later a cavity appears inside the compact mass of cells of the morula. The cavity is formed of crevice that appears among the inner cell mass and the cells of the trophoblast. Fluid is imbided into this cavity, so that it enlarges. The trophoblast becomes lifted off most of the inner cell mass remaining attached to it on one side only. This side corresponds late to the dorsal side of the embryo. A mammalian embryo at this stage is termed as a blastocyst.

Posted Date: 1/25/2013 5:59:35 AM | Location : United States







Related Discussions:- Cleavage and blastocyst, Assignment Help, Ask Question on Cleavage and blastocyst, Get Answer, Expert's Help, Cleavage and blastocyst Discussions

Write discussion on Cleavage and blastocyst
Your posts are moderated
Related Questions
Q. Functions of Colour in Foods? Let us now look at the different functions of colour in details, which are enumerated herewith: 1. The maturity of many fruits and vegetable

The PCR   (polymerase   chain   reaction)   is   an   extremely   simple   as   immensely powerful methods.  It permits enormous  amplification  of any particular  sequence of DNA

Q. What is an oligopeptide? How is it differing from a polypeptide? Peptide is the molecule formed by the union of amino acids through the peptide bond. Oligopeptide is a pepti

Name the methods for extracting phosphorous Phosphorus/phosphate - Phosphorous is estimated as phosphate. Some methods for extracting phosphorous are as follows:   Dyer met

Urine analysis - microhematuria with or without proteinuria may be seen. ECG - All patients with suspected IE should have baseline and follow up ECG which may reveal conduction

Why do membranes figure so prominently in eukaryotic cells? What essential function do they serve?


Q. Causes of Diabetic Ketoacidosis? The causes of Diabetic Ketoacidosis (DKA) are the following: - Missing of insulin injection - Infection - Trauma (injury) - Myoc


Q. How is the light from the sun transformed into chemical energy to be used by the living beings on earth? Light from the sun is converting into chemical energy contained in o