Neurosecretory cells and neurosecretion, Biology

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.

Posted Date: 2/4/2013 7:44:07 AM | Location : United States







Related Discussions:- Neurosecretory cells and neurosecretion, Assignment Help, Ask Question on Neurosecretory cells and neurosecretion, Get Answer, Expert's Help, Neurosecretory cells and neurosecretion Discussions

Write discussion on Neurosecretory cells and neurosecretion
Your posts are moderated
Related Questions
Q. What respectively are zygotic gametic meiosis, meiosis and sporic meiosis? Zygotic meiosis is the one that occurs in the haplontic haplobiontic life cycle and Gametes from a

Q. Explain about Genetic Diversity? Genetic diversity is the "fundamental currency of diversity" that is responsible for variation. This is the diversity of basic units of here

Q. What are the positions of myosin and actin molecules in the sarcomere before and during the muscle contraction? Schematically actin filaments attached perpendicularly to bot

Explain the life cycle of Water? The water cycle , or hydrologic cycle, is one of the most important processes to living organisms on Earth. Consider the following facts:

Explain amino acid composition In terms of amino acid composition, high radiation doses such as those required for sterilization (e.g. 25-27Kgy), do not change the content of c

how does impuses reaches the brain


Convulsive Disorders Definition Convulsion is a series of forceful in voluntary contraction and relaxation of voluntary muscles due to disturbance of brain function. It i

Adenine is one of the four nitrogen-containing bases occurring in the nucleotides, the building blocks of organic macromolecule group called as nucleic acids (DNA and RNA). Adenin

What is homogenization Emulsions may also be stabilized by a process known as homogenization, in which the size of the dispersed fat globules is greatly reduced to more or less