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

Can you define factor viii, Q. What is factor VIII? What is the genetic dis...

Q. What is factor VIII? What is the genetic disease in which this factor is absent? Factor VIII has the function of activating factor X that in its turn is necessary for the tr

Explain the term- horizons, Explain the term- Horizons These processes ...

Explain the term- Horizons These processes take a long time- may be a few thousand years to create a soil. As the time passes, the soil matures and generally becomes deeper and

Nervous system and sense organs, Nervous System and Sense Organs The n...

Nervous System and Sense Organs The non-chordates also perform a variety of activities such as feeding, digestion, locomotion etc. For this aim, they have corresponding organs

Protein requirement in chronic diarrhoea, Q. Protein Requirement in chronic...

Q. Protein Requirement in chronic diarrhoea? Requirements are increased only in chronic diarrhoea because of associated tissue depletion. An additional 10 g of protein may be r

Relate osseointegration with biointegration, Osseointegration Vs. Biointegr...

Osseointegration Vs. Biointegration In 1985, dePutter observed that there are two ways of implant anchorage or retention: mechanical and bioactive. Mechanical retention refers

What is lymphatic system in human biology, What is Lymphatic System in huma...

What is Lymphatic System in human biology? The lymphatic system maintains fluid balance and serves in protecting the body from disease. The primary organs of the lymphatic syst

Diversified animal group of the planet, Q. Which arthropod class is the mai...

Q. Which arthropod class is the mainly diversified animal group of the planet? How can this evolutionary success be explained? The insects are the animal group with most divers

What events occur during platelet plug formation, What is the role of plate...

What is the role of platelet plug formation in hemostasis? What events occur during platelet plug formation? Describe the circumstances that may induce inappropriate platelet plug

Sex-limited traits, can u show the different activities on the topic

can u show the different activities on the topic

Swine influenza, Swine influenza Swine influenza, a highly contagious ...

Swine influenza Swine influenza, a highly contagious disease affecting the respiratory tract of pigs, is c a use d  b y a  vir us b e lo nging t o the ge nus I nflu e nz a vir

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