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!
Interaction of insect hormones in the process of metamorphosis
The organs and the hormones usually included in metamorphosis of insects. This is since despite the fact that there may be around 1 million dissimilar insect species, there is a striking similarity in the endocrine function of dissimilar hemimetabolous and holometabolous insects. Figure depicts a schematic outline of the interaction of hormones in the metamorphosis of insects. On the basis of figure let us study how the actions of the several hormones bring about metamorphosis in insects. The moulting process, the beginning of metamorphosis, is initiated in the brain. The stimulus may be neural, hormonal or environmental, and causes the neurosecretory cells of the brain to release the activation hormone that after synthesis changes into the active hormone known as prothoracic opic hormone (PTTH). The PTTH stimulates the prothoracic gland to generate ecdysone.
Ecdysone after being transformed into its active form, the ecdysterone, stimulates growth and causes the epidermis to secrete a new cuticle, start the moulting process. The ecdysterone further stimulates the epidermal cells to synthesize enzymes which digest and recycle the components of the cuticle. As long as the juvenile hormone is present, the ecdysone-stimulated moult results in a new larval instar. In the last larval instar stage, the synthesis of juvenile hormone is decreased, causing its levels to drop below a critical threshold value. This again triggers the release of PTTH from the brain. The PTTH in turn, stimulates the prothoracic gland to secrete not usually large quantity of ecdysone. The resultant ecdysterone, in the relative scarcity of JH, causes the instar to pupate. In other word the occurrence of the subsequent moult in the larva in the relative scarcity of JH and abundance of ecdysone, shifts the organism from larva to pupa. Throughout the period of pupation the corpora allata do not release any juvenile hormone and the ecdysterone stimulates the pupa to metamorphoses into the adult insect.
Describe the location and structure of the pituitary gland and explain its structural and functional relationships with the hypothalamus.
Q. Assets and capital stock accounts? At the present extend the liabilities, assets and capital stock accounts in the Adjusted Trial Balance columns to the Balance Sheet column
Certain conditions such as excessive alcohol consumption can increase the ratio of NADH/NAD+ in the mitochondria. This will directly inhibit which of the following enzymes? -cit
Why are transgenics considered a threat to the environmental safety? Transgenics can be dangerous to the entire biosphere as the transfer of genes among species may have immed
Q. Categories of value of biodiversity? The value of biodiversity is often divided into two main categories: · UTILITARIAN (also known as instrumental, extrinsic, or use) v
Q. In hormonal terms why does menses occur? Menses is the endometrial monthly desquamation that occurs as the progesterone and estrogen levels fall after the regression of the
Explain about the Enteral feeding in elderly? Enteral, as you may already be aware, is defined as provision of nutrition support through the GI tract or by accessing the gut. Th
DEVELOPMENT OF GENETICS-A HISTORICAL PERSPECT As systematic study of genetics began, answers were sought to questions such as i) why are we like our parents? ii) why do org
What is the incubation period of an infection? Incubation period is the time interval among the infection by an agent that causes disease and the first signs or symptoms of th
Coronary Arteries The right coronary artery originates form the right aortic valvular cusp, its, SA nodal branch supplies the SA node and AV nodal branch supply the AV nod
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