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.
Determine Fat Soluble Vitamin Needs of school children and adolescents? ICMR (1990) does not give recommendations for vitamin D, E and K. Vitamin D is very important for skelet
Phytochrome - Development of plant You know that plants capture light energy during photosynthesis, now you are familiarised with another important and interesting role of lig
Give three examples of diseases caused by bacteria, Diseases caused by bacteria contain tonsillitis, blood poisoning, scarlet fever, tuberculosis, typhoid, diphtheria, food poi
What is life?
How does aggregation occur in sickle-cell anemia? Place the steps in the correct order from no aggregation to sickle red blood cell. Note that deoxyhemoglobin is generally in the T
Life cycle of Parasite - Protozoan The life cycle of the parasite in man begins when an infected mosquito, while biting and taking a blood meal, injects sporozoites into the
Define Chromatography - Basic Separation Technique? Chromatography is the most effective technique for the separation, purification and identification of one or more biological
Q. How different is the growth according to the biotic potential of a viral population from the growth according to the biotic potential of a bacterial population? The growth c
Why does geographical isolation lead to speciation? The Geographical isolation between groups of the same species leads to formation of a new species since it disallows crossin
Wat is the excretory organ of lizard
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