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

Define dietary management for burns, Define Dietary Management for Burns? ...

Define Dietary Management for Burns? Nutritional support is a major part of therapy for a patient with burns in view of the large catabolic losses, essential anabolic demands a

Describe what is respiration in dynamic auscultation, Describe what is Resp...

Describe what is Respiration in Dynamic Auscultation ? a) S 2 : Splitting of S 1 is audible during inspiration. b) Diastolic sounds and Ejection sounds: Inspiration augment

Biological conduits, Biological Conduits : Freeze dried arterial, bov...

Biological Conduits : Freeze dried arterial, bovine MA, human umbilical vein, cryo preserved umbilical vein or artery and omniflow sheep collagen tube grafts also have poor

What is the ability of two oxygens to remove h+ protons, What makes the clu...

What makes the cluster of atoms of carboxylic acid functional group an acid? a) a non-polar O-H bond near another electronegative oxygen. b) an ionic O-H bond near another el

Habitat for the worlds species, Q. Habitat for the worlds species? Natu...

Q. Habitat for the worlds species? Natural ecosystems provide habitat for the world's species. Forests, coral reefs and deep ocean bottoms house many species. Wetlands, through

How to placing the implants in immature grafted, Placing the Implants in Im...

Placing the Implants in Immature Grafted Sites One of the most common causes of prosthetically related implant failure is believed to be the too rapid loading of the implant su

Define repletion studies for studying nutrient requirement, Explain the Dep...

Explain the Depletion and Repletion Studies for studying nutrient requirement? This is an experimental procedure in which volunteer subjects are kept on a diet devoid of a part

Explain selective breeding methods, Explains how selective breeding methods...

Explains how selective breeding methods could be used to produce a population of cats with the short legs. Selective breeding E1: bases explanation on the assumption t

Explain purpose of therapeutic dietary adaptations, Purpose  of  Therapeuti...

Purpose  of  Therapeutic Dietary Adaptations A therapeutic diet is a quantitative/ qualitative modified version of a basic nutritious diet which has been tailored to suit the c

Probation/parole client , Write a report on a special probation/parole clie...

Write a report on a special probation/parole client and programs that have been situated to address this problem client. Focus on 1type of special requires offender (substance abus

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