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 about cold preservation - methods of food processing, Explain about...

Explain about Cold Preservation - methods of food processing? The metabolism of a living tissue is a function of the temperature of the environment. Low temperatures are used t

Define isolated soybean proteins in dairy type products, Define isolated so...

Define isolated soybean proteins in Dairy type products? Soybean protein isolates are used in non-dairy coffee whiteners, liquid whipped toppings, emulsified sour cream or chee

Define percentages of body fat values for athletes, Define Percentages of b...

Define Percentages of body fat values for athletes? Percentages of body fat values for athletes vary depending on the sex of the athlete and the sport itself. Male athletes par

What are the main cellular functions of potassium, Q. What are the main cel...

Q. What are the main cellular functions of potassium? Moreover being important for the osmotic regulation and for the acid-base equilibrium (pH) potassium is fundamental for th

Explain human development, Explain Human Development? Human development...

Explain Human Development? Human development begins with fertilization, and continues throughout life. Fertilization occurs when two sex cells, a sperm cell and an egg cell, jo

Determine reagents for determination of protein content, Determine Reagents...

Determine Reagents for Determination of Protein Content Using Biuret Method? Collect the following reagents to conduct the experiment: 1. 0.2 N NaOH solution - Dissolve 8 g

What are the illustrations of the criminal law, What are the illustrations ...

What are the illustrations of the criminal law? Illustrations of crimes' law: Illustrations of crimes are theft, reckless or murder behaviour. The major aim of illegal

Describe ecological phytosociological, Q. Describe Ecological phytosociolog...

Q. Describe Ecological phytosociological? Field studies are desirable for an understanding of the relationship of any group of plants. If it is not possible to study the plants

Classification scheme of protozoa, Classification Scheme of Protozoa ...

Classification Scheme of Protozoa Phylum Myxozoa Parasites of lower vertebrates especially fish and invertebrates. Phylum Microspora Parasites of inv

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