Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Threshold Value of Different Larval Tissues
Threshold value of dissimilar larval tissues for the thyroid hormone concentration
One of the main problems of metamorphosis is the co-ordination of developmental events. The tail should not degenerate till some another means of locomotion, namely the limbs develop, and the gills should not regress till the animal can employ its newly developed lung muscles. Kollros (1961) illustrated the possibility of this coordination that displays that different larval tissues have diverse threshold value for thyroxine. In other words the different larval tissues are sensitive to dissimilar concentrations of thyroid hormone.
This model is termed as the threshold concept. It has been observed that structures in the tadpole that change early during metamorphosis are more sensitive to and have low threshold value to thyroxine, than those which go through transformation at a later stage. As metamorphosis commences the thyroid hormone level slowly builds up and different events occur at different concentrations of the hormone. Experimental studies have revealed that tadpole pans that have a low threshold respond earlier during metamorphoses than those parts comprising a high threshold response. In other words, the threshold value reflects the order where metamorphic changes occur in normal development. In urodeles the bulging of eyes reacts to the weakest dose of thyroid hormone (minimum threshold) and thus is the first event in metamorphosis. This is followed by reduction of fin fold and the shortening and disappearance of external gills. After which takes place the closure of gill clefts and transformation of skin.
Evaluate the Moisture Requirement - The Concept of Water Activity We already know that moisture is one of the important factors for the survival of living species. As suc
Q What is the genetic material of a virus? How does that material act in viral reproduction? There is DNA viruses double strand or single strand DNA and RNA viruses double stra
Q. Source of the bacteria of Salmonellosis? The initial source of the bacteria is the intestinal tract of birds, reptiles, farm animals, humans and occasionally insects. As int
How would you design, in principle, an experiment to test the hypothesis that a certain variety of lettuce seed needed daylight in order to germinate? You would need as large
In about 80 per cent of ARF patients, ASO titre is significantly raised. ASO titres vary with age, geographical area and other fevers, which influence frequency of streptococcal in
Transported Soils These soils are formed from the weathered material which is transported and deposited away from the site of origin. Depending upon the nature of the transport
briefly deccribe the eggs snd follicles
Explain Standard titration - Estimation of Vitamin C in Lemon Juice? Pipette 5 ml of standard ascorbic acid solution into a 100 ml conical flask. Fill the burette with the dye s
The volume of Mrs. X's plasma was 3 liters before Ed administered the IV. Assume that there was a complete mixing of the administered water with her plasma but no mixing with her i
Q. Show the Impressions at first - Transitional Restorations? The dental technique will have modified the abutment to the desired shape and will now be able to fabricate the tr
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd