Pre-embryo - human development, Biology

Pre-Embryo - Human Development

About thirty hours after fertilization the zygote goes through mitosis giving rise to 2 blastomeres. These blastomeres go through further cleavages and by the 3rd day after fertilization, the tiny mass of cells reaches the uterus. Through this time it is a solid ball of cells called morula. In the next three days the morula is changed into a hollow ball of cells called blastocyst. The cavity of blastocyst is filled along with fluid secreted by the cells. One portion of the blastocyst consists of a concentrated mass of cells that will give rise to the entire body of the new individual. This is termed as the inner cell mass (ICM). Interestingly, each cell of this mass has the capability to develop into a complete individual. Identical twins are formed if the ICM splits. The outer ring of cells of the blastocyst surrounding its cavity is termed as trophoblast and gives rise to all the extra-embryonic membranes including much more of the placenta. This stage of development is important as the cells begin to move for the first time and become rearranged to shape the new individual. This procedure you might recall is the beginning of morphogenesis. However the major morphogenetic events occur during the third to eighth week.

Posted Date: 2/1/2013 4:35:28 AM | Location : United States







Related Discussions:- Pre-embryo - human development, Assignment Help, Ask Question on Pre-embryo - human development, Get Answer, Expert's Help, Pre-embryo - human development Discussions

Write discussion on Pre-embryo - human development
Your posts are moderated
Related Questions
In rats, the gene pigment (P) is dominant to no pigment (p). The gene for black (B) is dominant to the gene for cream (b). If a pigment gene (P) is absent, genes B and b are inoper

Explain the Precautions for Detection of Number of Bacteria in Milk? 1. Make a thin film of milk on the slide. 2. Do not over stain with methylene blue.  If over staining ha

BUCCAL CAVITY - Situated between upper & lower jaw. It is lined by stratified squamous epithelium. Separated from nasal chamber by palate. Palate forms roof of buccal cav

Diploidy and Haploidy :: In the chromosomal complement  given species  not all the  chromosomes are different  from each other .In fact these  are in pairs ,i.e.  every  two chrom

Q. What are the flat bones and the long bones? The main bones of the body may be classified as long or flat bones there are bones not classified into these categories. Instance

Oil Seed Meals as By-pass Protein Source The protein digestion in ruminants encompasses microbial transformation of dietary protein in the rumin. A varying portion of feed pro

DIGESTION OF FOOD MATERIALS Digestion, you know, involves  the mixing of  food, its movement through the digestive tract and chemical breakdown of the large ntolecules of  food

Management   In case of  small defects surgical treatment is not indicated because spontaneous closure may occur before one to two years of  age. Patient  is treated for conges

Factors that affects Oxygen Dissociation Curves - Temperature At higher temperature haemoglobin gives up oxygen more readily and the dissociation curve shifts to the right. Th

A knotted network of capillaries within a nephron, the glomerulus, receives arterial blood and is porous enough to allow much of the fluid portion of the blood to flow out of it al