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!
Neurosecretory Cells and Neurosecretion
We have before said that the neurosecretory cells are an important component of the non- chordate endocrine system. Of course, they are as well present in chordates. But unlike chordates, among non-chordates there are fewer epithelial endocrine glands, and thus they have to depend much more heavily on neurosecretory cells for chemical coordination. Berta Scharrer and Ernst Scharrer are considered progenitors of the concept of neurosecretion. Put in a easy way, it is the concept of neurones taking to secretary activity and producing hormones. We can simply locate and identify these NSCs in histological sections of the brain or ganglia, because they consist of plenty of stainable material or colloids, unlike ordinary neurones, which do not consist of any stainable colloids. We believe that these colloids are carrier substances for hormones. Very frequently we can prove the presence of such hormonal principles in such cells by experimental means. Not like the neurosecretory neurones, the ordinary neurones do not contain or secrete any hormones. Even though they release neurotransmitters at synapse and neuromuscular junctions, these are not released into blood and are short lived, not like the hormones secreted by NSCs. In the live brain of certain insects, in dissections, we can easily see the NSCs as tiny bluish white specks by the brain sheath, using a binocular dissection microscope. 'The neurosecretory material containing the hormone is produced mostly in the cell body, and is transported through the axons to the finger-like axon terminals. If we follow these axons, we see that these axonal endings frequently form swellings in association with blood spaces at a distance from the neuronal cell bodies. The secretory material is stored at the swellings and hormones are released from them in blood stream. Such types of organs seen in association with blood spaces and containing the swollen nerve endings of NSCs are called neurohemal organs. You will see that there are neurohemal organs in some non-chordates. Sinus gland in crustaceans and corpus cardiacum in insects are instances of neurohemal organs. Vertebrates also have their own neurohemal organs - the neural lobe of pituitary is one such neurohemal organ.
Q. Which kind of circulatory system do molluscs have? How can it be compared to the respiratory system of annelids? Molluscs, with the exception of cephalopods, have an open ci
Q. When Aflatoxigenic molds can occur? Occurrence: Aflatoxigenic molds can occur in warmer parts of the world and aflatoxicosis maybe produced in a wide range of tropical and s
Q. An mRNA molecule codifies only one kind of protein? Eukaryotic cells have monocistronic mRNA, that is each mRNA codifies only one polypeptide chain, Prokaryotes can present
Explain the Stages of alzheimer's disease? Stage I - There is an increased forgetfulness, anxiety and depression. Associated nutrition related changes include difficulty in
what is nomenalistic specie concept
How can we increase of total peripheral resistance? A. A decrease in the diameter of every arteriole. B. An increase of sympathetic discharge to all the smooth muscles
State the term - localisation scales The localisation scales are also empirically derived, being based on studies of patients with localised brain lesions. There are frontal,
Determine the Luria's testing methods The choice of using items selected by Christensen to determine Luria's testing methods was, in retrospect, probably less crucial than the
Failure to organize proper adjusting entries causes net income and the balance sheet to be in error. Using Micro Train Company as an instance this section has discussed and illustr
For a somatic cell with 2n = 4, which of the following is true? (Note: G1- growth phase 1, G2 - growth phase 2, M - metaphase, P - prophase and T - telophase) a. (Number of
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: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd