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

Stress testing after myocardial infraction, Q. Stress Testing after Myocard...

Q. Stress Testing after Myocardial Infraction? Many post infarction deaths are sudden and occur with in the first 6 months after infarction. Exercise testing from 10 days to we

Biochemical changes - consequences of aging, Biochemical Changes - Conseque...

Biochemical Changes - Consequences of Aging Several biochemical changes are correlated with aging. Detailed biochemical studies in rats have been carried out by Prof. M.S. Kan

Difference between cryptogamic and phanerogamic plants, What is the differe...

What is the difference among cryptogamic and phanerogamic plants? Cryptogamic (hidden sex organs) plants are those that do not show flowers or seeds. They comprise the bryophy

Determine inharmonious intraspecific ecological interaction, Why is canniba...

Why is cannibalism an inharmonious intraspecific ecological interaction? In cannibalism an individual eats other of the same species (occurs in some insects and arachnids). Sin

Modification of carbohydrate intake for specific disorder, Define Modificat...

Define Modification of Carbohydrate Intake for Specific Disorder? In our daily diet almost 60-7096' of energy is contributed by carbohydrates. Majority of them are comprised of

Describe briefly about acquired traits, Why acquired traits are not directl...

Why acquired traits are not directly related to the process of evolution? As acquired traits are not genetically determined, they cannot be passed on to offspring. Thus, they

Auxiliary food chains, Auxiliary Food Chains In addition to grazing an...

Auxiliary Food Chains In addition to grazing and detritus food chains there are other auxiliary food chains operated through parasites and scavengers. Some parasitic food chai

What proportion of children with down syndrome, What proportion of children...

What proportion of children with Down syndrome do you expect when women with down syndrome have children with men who have 46 chromosomes Justify your answer

Define the principle behind cyanmethemoglobin method, Define the Principle ...

Define the Principle behind Cyanmethemoglobin Method? The principle behind the cyanmethemoglobin method is as follow: Principle The haemoglobin is treated with a reagent con

Define the functions of vitamin a, Define the Functions of Vitamin A? V...

Define the Functions of Vitamin A? Vitamin A (retinol) is an essential nutrient needed in small amounts by humans for the normal functioning of the visual system, growth and de

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