Primary egg envelopes, Biology

Assignment Help:

Primary Egg Envelopes

These are the egg envelopes which develop in the ovary between oocyte and follicle cells in the space occupied by the interdigitating microvilli. Such envelopes have been named variously in different animals.

a) It is named as vitelline envelope or vitelline membrane in insects, molluscs, amphibians and birds.

b) In tunicates and fishes, it is known as chorion. In many sharks and bony fishes the primary envelope has striated appearance and is referred to as zona radiata representing the degraded microvilli of the growing oocyte. The perforation in the zona radiata becomes the micropyle through which the spermatozoa can enter the egg.

c) In mammals, the unstriated and modified zona pellucida is formed as a result of joint efforts of egg and follicle cells. While escaping the Graafian follicle mammalian oocyte carries on the surface of zona pellucida a layer of follicle cells known as corona radiata. The primary envelopes usually stick closely to the egg surface. These later on participate in the formation of fertilization membrane.


Related Discussions:- Primary egg envelopes

How genetic predisposition causing the underweight, How Genetic Predisposit...

How Genetic Predisposition causing the underweight? Mother's Health Status; Poor nutritional status of the girl child coupled with under nutrition during pregnancy results in L

Vital dye staining, Vital Dye Staining In this type of method, a piec...

Vital Dye Staining In this type of method, a piece of agar or cellophane soaked in the solution of a vital dye (Neutral Red, Nile Blue Sulphate, and Bismarck Brown etc.) is a

Management and nutritional intervention using mna, Define Management and Nu...

Define Management and Nutritional Intervention using MNA - Undernutrition? A. For those categorized as well-nourished They need only be reminded of the importance

What is an endospore - staining strategies, What is an endospore? An en...

What is an endospore? An endospore is a specialized, highly resistant, dormant structure formed within the vegetative cell of some bacteria e.g. Bacillus (rod), Clostridium (ro

Zoonoses disease-monkey b virus disease, Monkey B virus disease The di...

Monkey B virus disease The disease is caused by Herpesvirus simiae or B virus, a member of the herpes group of viruses. The infection occurs naturally among primates of the ge

Define food intake and energy requirements for humans, Define Food Intake a...

Define Food Intake and Energy Requirements for Humans? Many studies have shown that the subjects loose significant amounts of body mass; fat mass, as well as, fat free mass du

Zoonoses disease-staphylococcosis, Staphylococcosis The disease is caused ...

Staphylococcosis The disease is caused by the ingestion of preformed toxin released by Staphylococcus aureus. Epidemiology: Staphylococci grow in meat, dairy and bakery prod

Calculate the width of the implant, Width of the Implant The width of t...

Width of the Implant The width of the implant especially at the interface area is critical towards the success of the implant. It has been recommended that at least 1mm of bone

Formation of double bonds, In eukaryotes  the SER has enzymes  able to begi...

In eukaryotes  the SER has enzymes  able to begin  double  bonds into fatty acyl CoA molecules  in an oxidation  reaction  which uses molecular  oxygen.  This reaction is catalyzed

Is there such thing as good evaporation and bad evaporation, Hello I have b...

Hello I have been working with reptiles for a while and have been researching the incubation method known as egg suspended. This method is used with birds. Its placeing an egg on a

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd