Structural variations in vertebrate kidney, Biology

Assignment Help:

Structural Variations in Vertebrate Kidney

The structure of the vertebrate kidney is by no means universal. The mammalian kidney consists of an outer granular cortex and an inner striated medulla. The granular appearance of the cortex is due to the presence of glomeruli in this region. Medulla looks striated due to the parallel arrangement of blood vessels and tubules of the nephrons. In fishes, amphibians and reptiles, the renal tubules are short, are devoid of Henle's loop and there is no clear cut distinction between cortex and medulla. In birds there is some degree of spatial organisation of the nephrons so that a small central medulla can be discerned from the outer cortex. This division into cortical and medullary regions is most pronounced in the mammalian kidney.

It is the presence of Henle's loop that enables the avian and mammalian kidney to produce hyperosmotic urine. The ureteral urine in other vertebrates is either hypoosmotic or at best isosomotic to blood. However, terrestrial reptiles and birds produce a semi-solid or solid urine due to reabsorption of water in the cloaca. In birds and mammals, the ureteral urine itself is hyperosmotic to blood. The maximum urine osmolarity attained by the avian kidney is only about twice that of plasma. The urine concentrating ability of the kidney in mammals is related to the habitat. Desert animals produce highly concentrated urine and freshwater animals produce very dilute urine. The kidneys of some desert mammals can produce a urine which is 25 times more concentrated than the plasma. The beaver which has access to abundant water in the environment, on the other hand, has kidneys with only moderate ability to concentrate the urine.


Related Discussions:- Structural variations in vertebrate kidney

Classification of phytoestrogens, Classification of Phytoestrogens? Phy...

Classification of Phytoestrogens? Phytoestrogens can be divided into 3 main classes: - Isoflavones, - Coumestans and - Lignans. All are diphenolic compounds with st

Define gas liquid chromatography, Define Gas liquid chromatography? Thi...

Define Gas liquid chromatography? This is used for separating and identifying volatile compounds of fatty acids, hydrocarbons, sterols, amino acids and lipids, even from nanogr

filtration, It is the process of separating colloidal and suspended impuri...

It is the process of separating colloidal and suspended impurities from water by passing it through a porous bed made of fine sand and other proper sized granular materials. Filtra

Explain the recommended dietary allowances (rda), Explain the Recommended D...

Explain the Recommended Dietary Allowances (RDA)? The recommended dietary allowances are estimates of nutrients to be consumed daily to ensure the requirements of all individua

Skeletal system - face, FAC E - It lies under the anterior part of ...

FAC E - It lies under the anterior part of cranium. It is composed of 14 bones. These includes 2 nasals, 2 maxillae, 2 palatine, 2 zygomatic, 2 lacrymals, 2 inferior

Managing diarrhoea in children, Q. Managing diarrhoea in children? Mana...

Q. Managing diarrhoea in children? Managing diarrhoea in children is of great concern. The guidelines for the same are as follows: 1. The first objective is to rehydrate the

Essay, Need an essay for my biology class. Need to know if you can do it. ...

Need an essay for my biology class. Need to know if you can do it. Thank you Instructions. Essay Assignment: Experimental Design Now that you have completed several hands-on la

Worms, what is the mode of nutrition for worms?

what is the mode of nutrition for worms?

#titlecylintreta.., Aiscommoncellismwhatsk question #Minimum 100 words acce...

Aiscommoncellismwhatsk question #Minimum 100 words accepted#

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