Neurosecretory cells and neurosecretion, Biology

Assignment Help:

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.


Related Discussions:- Neurosecretory cells and neurosecretion

Ecretory system, excretory product of marine teleost

excretory product of marine teleost

What are coacervates, What are coacervates? Coarcervates are small stru...

What are coacervates? Coarcervates are small structures made of the aggregation of organic molecules under water solution. By electrical attraction the molecules join into bigg

What are the main cellular features of fungi, What are the main cellular fe...

What are the main cellular features of fungi? There are unicellular and pluricellular fungi. All fungi are eukaryotes and heterotrophs. Fungi have cells with cell wall made

Explain what is organismal ecology, Explain what is Organismal Ecology? ...

Explain what is Organismal Ecology? Ecology at the Level of Individuals: We define ecology as the study of the relationships between organisms and the relationships between o

Why the rate of photosynthesis does increases, Why the rate of photosynthes...

Why the rate of photosynthesis does increases, peak, and then reduces as temperature increases? Increasing the temperature initially accelerates the many chemical reactions in

What are the three main parts of a eukaryotic cell, Q. What are the three m...

Q. What are the three main parts of a eukaryotic cell? The eukaryotic cell can be separated into two major portions: the cell membrane that separates the intracellular space fr

Protozoa, What are the disadvantages of protozoa

What are the disadvantages of protozoa

Define atherosclerosis, Q. Explain Atherosclerosis? Atherosclerosis is ...

Q. Explain Atherosclerosis? Atherosclerosis is one of the most important causes of morbidity and mortality in developed as well as in developing countries. Atherogenesis occurs

Why soybean protein used as stabilized dispersions, Soybean protein used as...

Soybean protein used as stabilized dispersions Soybean protein concentrates have been used as stabilized dispersions in milk-like beverages and simulated dairy products, such a

Specialized structures that help the adhesion between cells, Q. What are th...

Q. What are the specialized structures that help the adhesion between cells? The structures responsible for the union of the epithelial cells are called cell junctions. The mai

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd