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 myocardial infarction, Q. Explain about Myocardial Infarction...

Q. Explain about Myocardial Infarction? It is an initial acute phase of cardiovascular disease caused by the blockage of a coronary artery supplying blood to the. Heart shows t

Determine the name of material used for bcc, Determine the name of Material...

Determine the name of Material used for BCC You must be interested to know about type of material you can prepare and some material is available in hospitals and clinics for us

What is polysaccharides, What is Polysaccharides? Polysaccharides:  M...

What is Polysaccharides? Polysaccharides:  Many monosaccharide subunits can be joined to form long, complex polysaccharide molecules. These complex sugars are often used to s

Nature of stress - responses of plants to stress, Nature of Stress - Respon...

Nature of Stress - Responses of Plants to Stress As mentioned in the preceding section, stress can be considered as any deviation in environmental condition from optimal for t

Bubble oxygenators type of oxygenators , Bubble Oxygenators: These ha...

Bubble Oxygenators: These have a mixing chamber where venous blood is collected and from the bottom end micro bubbles of oxygen are passed and as they rise to the top, gas ex

History of ecology, History of Ecology The roots of ecology lie in Natu...

History of Ecology The roots of ecology lie in Natural History, which is as old as human civilisation itself. As a matter of fact man indulged in ecology in a practical sort of

Define precautions for check the presence of rhodamine b, Define Precaution...

Define Precautions for Check the Presence of Rhodamine B? 1. Sample should be clean and dry. 2. Dispose off the paraffin oil carefully, so that it does not contaminate food/

What are the aerobic and anaerobic exercises, Aerobic and Anaerobic Exercis...

Aerobic and Anaerobic Exercises Generally, there are two types of exercises: - Aerobic - Anaerobic Aerobic exercises are those in which the patient spends calories fro

What are the uses of construction of a retaining wall, What are the uses of...

What are the uses of construction of a retaining wall? The retaining wall is constructed whenever space requirement do not allow the natural slope to be formed for an excavatio

Lab safety, Why should you not apply cosmetics while doing a lab experiment...

Why should you not apply cosmetics while doing a lab experiment in class?

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