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

Which is the type of nitrogen waste birds produce, Which is the type of nit...

Which is the type of nitrogen waste birds produce? Why does this feature, besides being an adaptation to the terrestrial environment, also mean an adaptation to flight? Birds a

What is the cell theory, Q. What is the cell theory? Cell theory assert...

Q. What is the cell theory? Cell theory asserts that the cell is the element unit of living beings. Before the discovery of the cell, it was not acknowledged that living bei

Explain about the radiation therapy, Explain about the Radiation Therapy? ...

Explain about the Radiation Therapy? Radiation therapy is one of the options for the treatment of various tumors. During the administration of radiation patients experience acu

Complications in dyslipidemia, Q. Complications in dyslipidemia? The co...

Q. Complications in dyslipidemia? The complications include: • Pancreatitis • Progressive atherosclerosis or asymptomatic coronary. Excess of triglycerides (hypertrigl

Describe in detail about retina, Describe in detail about Retina The r...

Describe in detail about Retina The retina is a highly complex layer of nervous tissue. The photoreceptors are rods and cones for scotopic and photopic vision respectively. Th

Types of cell wall, TYPES OF CELL WALL Cell wall differentiated into th...

TYPES OF CELL WALL Cell wall differentiated into the following layers : 1. Primary Cell Wall       2. Secondary Cell wall             3. Tertiary Cell wall 1 .

Molecular biology on which dna fingerprint is based, What is the fact of Mo...

What is the fact of Molecular Biology on which DNA fingerprint is based? The DNA fingerprint, the method of individual identification using DNA, is based on the fact that the D

Determine when the homologous chromosomes occur, In which period of meiosis...

In which period of meiosis does the pairing of homologous chromosomes occur? The pairing of homologous chromosomes is an essential step for meiosis because the rightness of the

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