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.
Bronchial Asthma Bronchial Asthma is characterized by increased responsiveness of the trachea and bronchi to various stimuli that cause narrowing of the airways and difficu
Explain the Techniques of cardian examination? Examiner should use the fingertips or the part just proximal to them for palpation. The chest should be completely exposed and el
assignment
Q. Enumerate different implant materials? Biomaterials fall into four categories: metal and metal alloys, ceramics (carbon included in this group) synthetic polymers, and natur
Which of the following is a false statement regarding the method of recombination or crossing-over? A. Crossing-over takes place during prophase I of meiosis B. Recombinatio
Describe the procedures involved in blood doping. What are the physiological mechanisms behind blood doping that attempt to achieve the desired outcome(s).
Healthy Person H takes a new drug named ANTICAMPCOLLDUCT that blocks the production of cyclic AMP (cAMP) in collecting duct epithelial cells in response to vasopressin binding to V
What is Ecology? The Ecology is the field of Biology that studies the relationship between living beings and between living beings and the environment.
What should we focus on During pregnancy? Our focus should be strongly on the preventive aspects of nutrition, identify women at-risk, recognize special needs for counseling, a
Tina administered 1 liter of sterile distilled water IV to a patient. Predict the direction (increase, decrease, no change) you would expect Tina's infusion to have produced in the
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