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

Symptoms and complications of atherosclerosis, Q. Symptoms and Complication...

Q. Symptoms and Complications of atherosclerosis? Symptoms Excessive weight, hypertension, high levels of cholesterol and triglycerides. Complications Myocardia

Name the two hormones produced by the pancreas, Name the two hormones produ...

Name the two hormones produced by the pancreas and say (a) in what circumstances, (b) in what way, they adjust the glucose concentration in the blood.

Explain about the secondary protein derivatives, Explain about the Secondar...

Explain about the Secondary Protein Derivatives? These are the products of further hydrolytic cleavage of the protein molecule, Examples include: a) Proteoses: Soluble in wa

Explain whipping foam method, Explain Whipping foam method? Whipping is...

Explain Whipping foam method? Whipping is the most common method used as it forms bubbles by cutting the surface and introducing air into liquid.  Repeated action makes the

Define nutritional requirements for extreme environments, Define Nutritiona...

Define Nutritional Requirements for Extreme Environments? Human beings have been able to survive and work under extreme environments of almost all regions of the earth, from po

Define some features of penicillium, Define some features of Penicillium? ...

Define some features of Penicillium? The identifying features of Penicillium are: 1. Mycelium consists of colourless, septate and branched hyphae, some of which grow inside

Representatives of each protochordate subphylum, Into which subphyla are th...

Into which subphyla are the protochordates divided? What are some representatives of each protochordate subphylum? Cephalochordates and Urochordates (or tunicates) are the two

What is the role of linked traits in genetics, What is the role of Linked T...

What is the role of Linked Traits in genetics? In his study of inheritance in the fruit fly, Morgan observed that certain genes are distributed together, or linked, rather than

Define the term - cerebral arteriosclerosis, Define the term - cerebral art...

Define the term - cerebral arteriosclerosis An embolism can be a blood clot, a bubble of air, a deposit of oil or fat, or a small mass of cells detached from a tumor. Reduction

Explain the characterstics of acute ar murmur, Explain the characterstics o...

Explain the characterstics of Acute AR Murmur ? Characteristic: Relatively low pitched, decrescendo diastolic murmur, which may end part way through diastole. These murmurs ar

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