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
You are studying how proteins are targeted to the mitochondria. MIP1 is in the mitochondrial inner membrane, whereas MIP2 is targeted to the matrix. You are most interested in how

Sporadic exertional  rhabdomyolysis (azoturia, tying up in horses) Azoturia is a metabolic condition of horses that is characterized by reluctance to move and poor performance.

What type of respiration does earthworm has ? In many complex animals, the cells of internal organs are distant from the outside environment; respiratory systems provide the passag

The various types and their description of Heart failure are as follows:  Left Sided Versus Right Sided Heart Failure   Predominantly left sided failure is seen in left ventr

Excluding the effects of cardiac output and hormones, describe the other factors that may affect blood pressure and blood flow in a middle-aged man who is exercising in an aerobics

Explain two ways in which a changing climate may impact the nutrient cycle. Predict  the effect on turnover.

describe the discovery of new fossil evidence for evolution

Explain about functions of the lacrimal apparatus. Tear Secretion Aqueous tears are secreted by the main (reflex secretion) and accessory (basic secretion) lacrimal

What is Intracardiac Repair of Tetralogy of Fallot ? Technique : The essential steps are: (I) relief of right ventricular outflow obstruction, and (2) closure of ventricular

Q. What is the stage of the cardiac cycle during which the ventricles are filled? The filling of the ventricles with blood take place during diastole.