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

Define prevention of idd - iodized salt distribution, Define Prevention of ...

Define Prevention of IDD - Iodized salt distribution? Many approaches to reduce iodine deficiency has been formulated. Some of these are reviewed herewith: Iodized salt dist

Define discovery of other essential nutrients, Define Discovery of other Es...

Define Discovery of other Essential Nutrients? Following the identification of the food factors involved in beriberi, pellagra and scurvy, the search was on for other water-sol

Define basic function of secretin in the digestive process, Q. Where is it ...

Q. Where is it produced and what is the function of secretin in the digestive process? Secretin is made in the duodenum the chyme acidity causes the duodenum to release this ho

Plants - slow moving waters, Plants - Slow Moving Waters Plant life is...

Plants - Slow Moving Waters Plant life is abundant in this habitat and includes rooted vascular plants such as pond weeds and grasses, firmly attached aquatic mosses and multi

Rituals , Rituals: The social life of  the earliest human groups or tri...

Rituals: The social life of  the earliest human groups or tribes revolved around food gathering. To begin with, they must have collected anything they could eat-seeds,  nuts, f

Explain community dietitians, Explain Community dietitians Community d...

Explain Community dietitians Community dietitians or  nutritionists  may  counsel  individuals and  groups on  sound nutrition practices  to  prevent  disease, maintain  healt

Freshwater biomes, Low levels of dissolved salts characterise the freshwate...

Low levels of dissolved salts characterise the freshwater biomes. The salt content of fresh water is about 0.005 percent. The freshwater biomes consist of inland bodies of standing

Permeability, Permeability Permeability is the ability of a soil to tra...

Permeability Permeability is the ability of a soil to transmit water or air. Permeability or infiltration rate is measured in terms of the rate of water flow through the soil i

Disorder of parathyroid function, Disorder of Parathyroid Function: Th...

Disorder of Parathyroid Function: The disorders of parathyroid function may  either  lead  to increased production or decreased production of parathormone.  Hypoparathyroid

The physical environment - stress of hospitalization, The Physical Environm...

The Physical Environment   The actual hospital environment is another factor that may be stressful for the child and family. There are many unfamiliar sights, sounds and smells

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