Secondary egg envelopes, Biology

Assignment Help:

Secondary Egg Envelopes

These are secreted by oviducts and other accessory parts of genital organs while the egg is passing through them from ovary to the exterior.

a) In ovoviviparous sharks the egg is surrounded by a hard shell secreted by shell glands of the oviduct. The shell is drawn out as twisted horns which serve to entangle the egg among sea weeds.

b) In amphibians, the eggs are surrounded by a layer of jelly which protects the egg from adverse effects of sun rays, abrasion as well as from predators (because of its bad taste). The jelly absorbs water and swells.

 c) In birds, reptiles and monotremes, the secondary envelopes include the white of egg surrounding the yolky ovum, followed by inner and outer shell membranes (which are in close contact with one another) and the outermost calcareous shell which is 'porous. The shell is elastic and compressible when the egg is laid but it hardens on exposure to atmosphere.


Related Discussions:- Secondary egg envelopes

What are the personal protective equipments for infection, What are the per...

What are the personal protective equipments for infection control? Personal protective equipments for infection control are: Protective clothing Masks Protective eyewe

Bovine parainfluenza, Bovine parainfluenza This virus belongs to the g...

Bovine parainfluenza This virus belongs to the genus Respirovirus in the subfamily Paramyxovirinae of family Paramyxoviridae. It causes respiratory syndrome in cattle and shee

What is classic repair in ventricular aneurysm, Classic Repair (Linear repa...

Classic Repair (Linear repair) :  The operation is done under cardio pulmonary bypass, through median sternotomy. If additional CABG is required, conduit harvesting is done.

Explain kingdom animalia, Kingdom Animalia Multicellular, heterotrophic, ...

Kingdom Animalia Multicellular, heterotrophic, eukaryotes, tissues are specialised and most of them have organs, mostly highly responsive. Only gametes are haploid, fertilisation

Mycroboilogy mycoplasma, How we write assimgment about mycobiology of mycop...

How we write assimgment about mycobiology of mycoplasma in detail

What is the connection between tissue fluid and plasma, What is the connect...

What is the connection between tissue fluid, plasma and lymph? Tissue fluid is plasma (minus its proteins) which has leaked out of the capillaries. Lymph is tissue fluid which

DNA replication, What is cDNA and what is its function and mechanism of act...

What is cDNA and what is its function and mechanism of action?

How biocompatibility of materials affect osseointegration, Q. How Biocompat...

Q. How Biocompatibility of materials affect osseointegration? Materials available of present are cpTi (commercially pure Titanium) Ti - 6AI - 4V (Titanium - 6 Aluminum - 4 Vana

What is h shaped incision and what is its purpose, Q. What is H shaped inci...

Q. What is H shaped incision and what is it's purpose? This type of incision is especially useful for: The anterior maxilla or mandible. Accurately identified implant

What are cd4 lymphocytes, What are CD4 lymphocytes? What is the relationshi...

What are CD4 lymphocytes? What is the relationship between these cells and HIV? How does HIV replicate? CD4 lymphocytes are T helper lymphocytes that there in their plasma memb

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