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.
Define Food Sources of Calcium? Dairy products are of course the primary source of calcium followed by grains and pulses. Among the millets, ragi contains substantial amount of
Vitamin A (Retinol) Purified vitamin A is a viscous yellowish oil. It is freely soluble in most organic solvents such as methanol, ether, acetone, chloroform and petroleum ethe
what is .groups of protozoa?
Preparation of the standard curve for haemoglobin? Label 6 clean dry rest tubes and label them as S1 -S6 Add 5 ml of Drabkin's solution to test tube numbers S2 - S6
Define the Process of Feeding 0-6 Months Infant? The term exclusive breast feeding is used when all fluids, energy and nutrients are provided by breast milk, with the possible
Why Fats are essential for meeting nutritional need of essential? Fats are essential for meeting nutritional needs of essential, fatty acids like linoleic acid (n-6) and alpha
Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4
Q. Can you explain Aneurysm of Aorta? CXR findings are an enlargement of the involved portion of the aorta. A focal dilatation may simulate a mass or adenopathy. A more general
Where does most of the water resorbed after glomerular filtration go? What are the other substances resorbed by the nephron tubules? Only 0.5 to 1% of the glomerular filtrate i
In the scientific competition against fixism what are the main arguments that favor evolutionism? The major arguments in favor of evolutionism are paleontological, from the stu
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