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

Explain nutritional support management - cancer patient, Explain about the ...

Explain about the Nutritional Support Management? Tube feeding is usually started. If tube feeding is not possible, parenteral nutrition through peripheral vein or through the

Explain the coliforms - microbiological study of water, Explain the Colifor...

Explain the Coliforms - Microbiological Study of Water? These are widely used indicators which belongs to the family Enterobacteriaceae and make up about 10% of the intestinal

Explain blood vessels that carry blood, Explain Blood Vessels that carry bl...

Explain Blood Vessels that carry blood? Blood vessels that carry blood away from the heart to the lungs or to the rest of the body are called arteries. The walls of arteries ha

Sources of food contamination, All plants and animals have a natural microf...

All plants and animals have a natural microflora associated with them. For example, the plants have a natural microflora associated with the surface of roots, stems, leaves e

Classification of nephrotic syndrome, Classification of Nephrotic Syndrome ...

Classification of Nephrotic Syndrome In childhood, nephrotic syndrome can be divided into minimal lesion nephrofic syndrome and  significant lesion nephrotic syndrome dependin

Define protection against poisoning - function of vitamin e, Define Protect...

Define Protection against poisoning - Function of Vitamin E? 1) Protection against poisoning: It protects liver from injury due to carbon tetra chloride poisoning. 2) Pr

Draw a diagram of transverse section of mammalian bone, Draw a diagram of t...

Draw a diagram of transverse section of mammalian bone and label the following parts in it: (i) Haversian canal (ii) Lacuna containing osteocytes (iii) Canaliculi

Sulphur cycle - nutrient cycles, Sulphur Cycle - Nutrient Cycles The s...

Sulphur Cycle - Nutrient Cycles The sulphur cycle is mostly sedimentary except for a short gaseous phase. The large reservoir of sulphur is in the soil and sediment where it i

What is genetic recombination and evolution , What is Genetic Recombination...

What is Genetic Recombination and Evolution ? Variation among the offspring of living organisms results from genetic recombination through sexual reproduction and mutation. Va

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