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 is end-to-end anastomosis subclavian flap aortoplasty, What is End-to-...

What is End-to-End Anastomosis with Subclavian Flap Aortoplasty ? The two operations can be combined as a single procedure. Medially end-to-end anastomosis is done between the

Explain about the biuret method, Explain about the Biuret Method? The B...

Explain about the Biuret Method? The Biuret reaction was one of first colorimetric assays developed for protein estimation. It is most often used in applications requiring a fa

The rapeutic nurse, THE RAPEUTIC NURSE: Development of  therapeutic  n...

THE RAPEUTIC NURSE: Development of  therapeutic  nurse patient  relationship is the basic requirement  of nursing. A helping relationship  in nursing may be explained as an in

What is the life cycle of trypanosoma cruzi, Q. What is the life cycle of T...

Q. What is the life cycle of Trypanosoma cruzi? The Trypanosoma cruzi is a heteroxenous parasite that is it has an intermediate host, the triatomine bug, and a definitive host,

Physical examination of a child, PHYSICAL EXAMINATION OF A CHILD This ...

PHYSICAL EXAMINATION OF A CHILD This practical as you have seen above deals with assisting in various diagnostic procedures of a child. The first responsibility of you as a

Define prevalence of weight management, Define Prevalence of Weight Managem...

Define Prevalence of Weight Management? WHO (1998) estimates that in developing countries about 245 million adults are moderately underweight and 93 million severely underweigh

Heat production, Heat Production In the Homeotherms heat production m...

Heat Production In the Homeotherms heat production must be elevated if the ambient temperature falls below the critical temperature. Although all metabolic processes result i

Define use of isotopically labelled nutrients, Define Use of Isotopically L...

Define Use of Isotopically Labelled Nutrients? Nutrient Turnover Radioactive labelled nutrients are used to know the total body pool and the compartment in which it is stored.

Role of glucocorticoids in controlling gene expression, Define Role of Gluc...

Define Role of Glucocorticoids in controlling gene expression? Glucocorticoids are another class of hormones involved in the regulation of lipogenic enzymes, but their role in

Describe phosphorylated for atp formation, Q. What is compound that is phos...

Q. What is compound that is phosphorylated for ATP formation? What is resulting compound when ATP liberates energy? adenosine triphosphate or ATP is formed after the binding of

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