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

Compute how much of the absorbance of the bsa, For a sample containing both...

For a sample containing both protein and nucleic acid, the absorbance measured at a particular wavelength will be the sum of contributions from both types of molecule. Using the pr

Corpus luteum in human females.., what is the fate of corpus luteum if egg...

what is the fate of corpus luteum if egg gets fertilised ?

Explain the resorbable barriers - root perforation, Explain the Resorbable ...

Explain the Resorbable Barriers - Root Perforation It is successfully control internal bleeding through cronal access It is intended to forced in the bone, not left wi

Nursing assessment - hypospadias, Nursing Assessment Hypospadias can b...

Nursing Assessment Hypospadias can be observed by nurse or parents at birth. The child presents with abnormal pattern of voiding and presence of chordae. The stream of ur

How drug intolerance in tuberculosis, Drug Intolerance For patients wh...

Drug Intolerance For patients who cannot tolerate rifampin, alternative regimens include 9-12 months of isoniazid, ethambutol and pyrazinamide, with or without a fluoroquinolo

Why is genetic homozygosity dangerous, Why is genetic homozygosity dangerou...

Why is genetic homozygosity dangerous to a nearly extinct species? Genetic homozygosity leaves no variation for natural selection to act on. Thus, a new disease could wipe

What information from the patients symptoms, A 16 year old boy named Jake w...

A 16 year old boy named Jake was admitted into the emergency room complaining of headache, fever, stiffness of abdominal muscles and difficulty swallowing. The doctor on staff bega

Food gathering and hunting , Food Gathering and Hunting : Food Gatherin...

Food Gathering and Hunting : Food Gathering and Hunting In order to live, man needed to eat and to protect himself from the weather and animals.  For both purposes he found it

Can obesity causes the cardiovascular disease, Q. Can Obesity causes the ca...

Q. Can Obesity causes the cardiovascular disease? Obesity is established as a leading predictor of CAD and is associated with several cardiovascular risk factors like cholester

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