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

ZOLOGY, The destruction of the ozone layer may be responsible for an increa...

The destruction of the ozone layer may be responsible for an increase in

Duration limit of the qrs, Q. Duration limit of the QRS? The duration o...

Q. Duration limit of the QRS? The duration of the QRS is usually reduced slightly during exercise. Because catecholamines increase conduction velocity in the Purkinje fibers an

Phylum Arthropoda, What is an example of animal coming from the phylum art...

What is an example of animal coming from the phylum arthropoda?

Evaluation of health services, CONCEPT AND MEANING OF EVALUATION: Eval...

CONCEPT AND MEANING OF EVALUATION: Evaluation of programmes is critical for measuring various community health services The ultimate reasons for doing evaluation is to ensure

Explain about the salting - methods of food processing, Explain about the S...

Explain about the Salting - Methods of Food Processing? Salting: Salting, especially of meat, is an ancient preservation technique. Food is treated with salt or a strong salt s

Describe the incorporated protectants rules, Which actions proposed in 1994...

Which actions proposed in 1994 were not finalized in the recently issued plant- incorporated protectants rules ? EPA has shown in a supplemental notice, which is part of the fi

Define the management of obesity, Define the Management of Obesity? Man...

Define the Management of Obesity? Management of obesity should be taken up with a clear understanding of the harsh realities of the problem and its outcome. It may be a frustra

What are colonies and societies, Q. What are colonies and societies? Th...

Q. What are colonies and societies? The Colonies are functional integrated aggregates formed by individuals of the similar species. The Colonies are often confused with a singl

Pre-operative teaching in cardiac surgical operation, Pre-operative Teachin...

Pre-operative Teaching Brief explanation-anatomy, physiology of the cardio-respiratory system.  The disease and the operation which is going to be done.  Operati

Valve separate the right ventricle from the pulmonary artery, Q. What is th...

Q. What is the valve that separates the right ventricle from the pulmonary artery? Why is that valve important? The pulmonary valve is important to prevent blood from the pulmo

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