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 the Process of dna technology - Enzymes, Explain the Process of dna...

Explain the Process of dna technology Procedures involving recombinant DNA technology has been used to increase the yield of enzymes already produced by the microorganisms, e.

Regulation of pfk and fructose 1, When the level of AMP is high, this shows...

When the level of AMP is high, this shows the requirement for more ATP synthesis. AMP stimulates PFK increases the rate of glycolysis and inhibits fructose 1 and 6- bisphosphatase

Explain the categories of fats and oils, Categories of Fats and Oils Yo...

Categories of Fats and Oils You already know that fatty acids are the lipid-building blocks. It is customary to divide  the fatty acids into different groups, e.g.,  saturated

Umbilical and inguinal hernia, Umbilical Hernia: An umbilical hernia  ...

Umbilical Hernia: An umbilical hernia  is protrusion of a portion of intestine  through  the umbilical ring (an opening in the muscular area of the abdomen where the umbilical

Evaluation of disabilities, Problem: Evaluation of disabilities due to ...

Problem: Evaluation of disabilities due to occupational diseases (a) Describe the following terms: "impairment", "disability "and "handicap" (b) Show how the evaluation o

Define the term hot water blanching, Define the term Hot water blanching? ...

Define the term Hot water blanching? A appropriate water-blanching process in traditional processing is as follows: The sliced material is placed on a square piece of cl

Define iron status of the individual, Define Iron Status of the Individual ...

Define Iron Status of the Individual Lastly, iron status of the individual is a floury determinant of how much iron is absorbed. On a mixed diet with some haem iron, the overal

What is an example of evolutionary novelty, Compared to amphibians what is ...

Compared to amphibians what is an example of evolutionary novelty present in beings of the class Reptilia against the loss of water through the skin? The reptile skin is kerat

Importance of biodiversity, T hese are some important uses of biodiversity....

T hese are some important uses of biodiversity. 1.   Source of food, medicines and drugs: (a)       Wheat, rice and maize are three carbohydrate rich crops and contribute

How to use a chi-square test, The following progeny genotypes were observed...

The following progeny genotypes were observed: 73 AaBb, 64 aabb, 279 Aabb, 303 aaBb. Using a chi-square test, test whether these two loci show independent assortment? How would

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