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

What are the vascular bundles, What are the vascular bundles? How does conf...

What are the vascular bundles? How does configuration of the vascular bundles within the stem differentiate monocots from dicots? The Vascular bundles are segments of xylem and

#title. Principles of Biology, Does greater light 80 cm instead of 20 cm p...

Does greater light 80 cm instead of 20 cm produce more photosynthesis on plants? Why or why not

Blood be enhanced during vigorous activity, The percentage of oxygen absorb...

The percentage of oxygen absorbed from the air in the lungs is always about the similar, so how can the oxygen supply to the blood be enhanced during vigorous activity? Breathi

Plant physiology, application of apical dominace in horticulture and agricu...

application of apical dominace in horticulture and agriculture short notes

Explain negative staining technique, Explain Negative Staining Technique? ...

Explain Negative Staining Technique? Here, a stain has a negatively charged chromophore that is repelled by the negative bacterial surface. It results in indirect staining of m

Express the term - amnion, Express the term - Amnion One of the extraem...

Express the term - Amnion One of the extraembryonic membranes found in terrestrial vertebrate. The amnion is filled with fluid and the developing embryo of reptiles, birds, and

How lysosomal enzymes involved in the scavenging of aged, How Lysosomal enz...

How Lysosomal enzymes involved in the scavenging of aged Lysosomal enzymes are also involved in the scavenging of aged and damaged cells. In several diseased states and also by

Urine examination of the diabetes patient, Q. Urine Examination of the diab...

Q. Urine Examination of the diabetes Patient? Generally when blood testing facilities are not available, urine is tested for the presence of sugar. A urine sample shows presenc

Nutrition, prove oxygen is produced during photosynthesis in the presence o...

prove oxygen is produced during photosynthesis in the presence of light

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