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!
Spiral Cleavage - Metazoa
In Spiral Cleavage, however, the third and fourth cleavage planes are oblique to the polar axis and the resulting blastomeres do not lie on top of one another but above the furrows between the cells. The spindles during the third cleavage are arranged in the form of a spiral, therefore, the name spiral cleavage. This type of cleavage is seen in all invertebrate except the echinoderms (i.e. in annelids, molluscs, arthropods nemertenes and polyclad planarians).
Figure: Spiral cleavage showing transition from 4 to 8 to 16 cell stage
Spirally cleaving embryos are said to have mosaic or determinate form of development. This means that the organ forming regions of the egg are strictly localised in the egg from the very beginning and the fate of the blastomeres is determined early. If the blastomeres are separated, each will continue to develop up to a certain time as though it was a part of the whole and give rise to defective, partial embryos. In the early embryos an unidentified cytoplasmic factor is segregated into one of the blastomeres, the mesentoblast (this is also called the '4 d' cell) which gives rise to the future mesoderm.
The NYQUIST LIIMIT-It is a sampling phenomenon, which limits the maximum fiequemcy shift measurement to one half of the sampling frequency (PRF). By its nature, pulse wave
Define Ecosystems science and large-scale ecology? Many of today's most pressing problems are regional or global in nature including for instance, the effects of land cover and
Ordinary share capital This type of Equity finance is raised from the public from the sale of ordinary shares to the shareholders. This finance is presented to limited compan
Pseudorabies Pseudorabies is a viral disease caused by pseudorabies virus (PRV) that is classified under family Herpesviridae. This disease is also known as “Aujeszky’s diseas
In hormonal terms why does menses occur? Menses is the endometrial monthly desquamation that happens as the estrogen and progesterone levels fall after the regression of the co
Transcription in eukaryotes, a much more complex procedure than in prokaryotes. In the eukaryotes, translation and transcription take place in several cellular compartments that ar
Blood from a donor is sterile and stored in a sealed bag, but it is still kept at 4°C. What is the advantage of keeping it at this low temperature? At 4 °C, enzyme activi
What is the Host Factors of implants These factors are very important and it is essential for the clinician to keep these in mind during the diagnosis and treatment planning st
Q. How to Investigate mitral stenosis by Electrocardiogram? Electrocardiographic changes are not specific for mitral stenosis and are never diagnostic for any valvular heart di
Adefovir dipivoxil (Hepsera) This phosphonate nucleoside analog, administered as the oral prodrug, inhibits replication of HBV, including variants resistant to lamivudine. Ade
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