Thesaurer Thursday

Langerhans Cells & Islet of Langerhans

Langerhans Cells are not related to Islet of Langerhans. Both were discovered by Paul Langerhans, physician and anatomist from Germany.

Langerhans Cells are dendritic cells found in skin and mucosa, all layers of epidermis and are most prominent in stratum spinosum (a layer of epidermis characterized by presence of desmosomes and keratinocytes that synthesize cytokeratin). Langerhans' Cell Histiyocytosis

 Islets of Langerhans are cells scattered throughout the pancreas which include cells that sense sugar level. in the blood. They are approximately1-2% of the entire organ. In Type I Diabetes body's immune system mistakenly  attacks and destroys these cells, thereby making the body incapable of producing Insulin

Neurohormones,Neurotransmitters, Neuromodulators & Neuroregulators

The terms are commonly confused. I am trying to clarify using reference books that I have and material available on internet.
Neurohormones are hormones secreted into the peripheral circulation from nerve terminals in the posterior pituitary gland. e.g., Vasopressin, oxytocin and hypothalamic releasing factors (GnRH, CRH,GHRH) or inhibiting factors (e.g., SST) are released into a specialized pituitary portal vasculature as neurohormones that direct secretion of anterior pituitary hormones.

Neurotransmitters
They conduct information synaptically between neurons. A peptide released from the fiber terminal of one neuron into the synaptic cleft to act on the membrane of another neuron is a neurotransmitter. This action is relatively fast and short lasting.
Excercise on Neurotransmitters

Neuromodulators

They affect the response of a neuron to other neurotransmitters released from some or other neurons.

In neuroscience, neuromodulation is the process in which several classes of neurotransmitters in the nervous system regulate diverse populations of neurons (one neuron uses different neurotransmitters to connect to several neurons). As opposed to direct synaptic transmission, in which one presynaptic neuron directly influences a postsynaptic partner (one neuron reaching one other neuron), neuromodulatory transmitters secreted by a small group of neurons diffuse through large areas of the nervous system, having an effect on multiple neurons. Examples of neuromodulators include dopamine, serotonin, acetylcholine, histamine and others.(paragraph courtesy )

Neurotransmitters vrs Neuromodulators

Neurotransmitters:  -  elicit the changes in membrane potential 

-  can be small MW classic neurotransmitters or neuropeptides or gaseous nt.

-  rapid, brief action

Neuromodulators:    -  typically, they do not affect membrane potential themselves, but modulate (enhance or     suppress) the effects of neurotransmitters at the synapse

-  typically neuropeptides; one particular peptide may serve a neurotransmitter role at one synapse and a neuromodulator role at another synapse

-  slow, prolonged action

-  small MW neurotransmitters and peptide neuromodulators often coexist and corelease

Neuroregulators

Neuropeptides such as endorphins distributed throughout the CNS are expressed at many levels of the neuroaxis and act as neuroregulators via opiate receptors and function as analgesics.Opioid peptides e.g., Methionine enkaphaline, leucine enkephalin and  β-endorphins.

 

Q: How can one single peptide (neurotransmitter) affect the function of a complex network (i.e., modulate a complex neural function)?

 Ans:

1.  As a neurotransmitter at a strategic point in a neural network.

Inhibition of the peptide action suppresses the activity of the network.

Stimulation of the peptide action increases the activity of the network.

2.  As an endocrine agent present in the blood.

The peptide triggers the action of the neuronal network  ® ® complex response

3.  As both an endocrine agent triggering and a neurotransmitter sustaining the function of a network.

-  opioid peptides in pain suppression

-  cholecystokinin in the regulation of feeding

  

Synthesis and Storage of Neurotransmitters

Neurological Control

Thesaurer Thursday

I found an interesting article in my mail. I am sharing it with you.  Source is Ezine Articles.

Bear these tips in mind to avoid the bear baring his teeth. Don't know which bear? It's the one bearing the bared tray.

Much of language is learned through hearing and practice - through conversation. We rely on context to give meaning, but what happens when we're led astray by what we hear?

Misused words and poor grammar.

No problem - we've got the remedy! Discover the true meaning and maintain a keen eye on your articles for this batch of misused words:

e.g. vs. i.e.

e.g. - Latin abbreviation for "exempli gratia," which means "for example." Use this abbreviation when providing examples that's not a finite series.

Incorrect: Greg is a huge fan of cyborgs, i.e., the Terminator, Inspector Gadget, and RoboCop. Correct: Greg is a huge fan of cyborgs, e.g., the Terminator, Inspector Gadget, and RoboCop.

i.e. - Latin abbreviation for "id est," which means "that is." Use this in place of “in other words,” when you’re making something more clear, or when providing a finite series.

Incorrect: Standing behind a horse can result in broken ribs, e.g., you’re more likely to get kicked. Correct: Standing behind a horse can result in broken ribs, i.e., you’re more likely to get kicked.

accept vs. except

accept - to consent to receive; to agree to undertake.

Incorrect: I except your challenge. Correct: I accept your challenge.

except - not including; other than; to exclude; a conjunction that conveys an exception.

Incorrect: "I can resist everything, accept temptation." -- Oscar Wilde Correct: "I can resist everything, except temptation." -- Oscar Wilde

advice vs. advise

advice - information; guidance or recommendations typically given by an expert.*

Incorrect: Need advise? We've got answers! Correct: Need advice? We've got answers!

*Tip: Advice is a noun that can be singular or plural, like moose.

advise - to offer suggestions; to recommend.

Incorrect: We can advice you on all of your legal needs! Correct: We can advise you on all of your legal needs!

bear vs. bare

bear - to carry (i.e., physically or mentally); a mammal with thick fur and a short tail (e.g., grizzly bear, teddy bear, etc.).

Incorrect: Bare in mind, you should never trust a bear. Correct: Bear in mind, you should never trust a bear.

bare - not clothed or covered; to uncover; to expose.

Incorrect: My bear hands turned blue in the cold. Correct: My bare hands turned blue in the cold.

forth vs. fourth

forth - out from a starting point and forward or into view.

Incorrect: From that day fourth, Gerald never looked at eggplant the same way. Correct: From that day forth, Gerald never looked at eggplant the same way.

fourth - a quarter; constituting number four in a sequence; 4th.

Incorrect: A forth of the sales can be attributed to cats. Correct: A fourth of the sales can be attributed to cats.

As always, we are on the hunt for more and more commonly misused words to help you achieve 100% error-free articles. If you have any misused words you'd like to see added to the Top Misused Words series, get them off your chest! Click here to share your suggestions in the comments section of this post on the Article Writing and Insights blog.

Not familiar with this series? Check out Top Misused Words Parts I, II, III, and IV for more great proofreading and grammar tips!

Courtesy: Ezine Articles 

Thesaurer Thursday

 Toxin,Venom and Poison

Toxin, I have talked about earlier, is an antigenic poisonous substance that is produced within the living cells e.g., bee sting venom. In this post we will see the difference between toxin, venom and poison.

Toxins are produced in the living cells, and venoms are toxins that are injected by a bite or sting to cause their effect. Poison is a substance which is chemically and biologically produced but absorbed through the epithelial lining of the gut or skin.

It is seen that there are certain venomous animals and there are others that are called poisonous animals but not venomous. What is the difference between a venomous and a poisonous animal?

Well, it all depends on how the the biologically produced poisonous thing or the toxin is delivered. If the toxin  is injected in the vein of the animal by the other animal which produces it and resorts to the aggression for self defence, it is called a venom. But if the harm is caused upon eating or touching anything of plant or animal origin, the plant or animal is called poisonous.

Examples of Poisonous Animals. Wikipedia

Thesaurer Thursday

We encounter words that cause confusion or are used incorrectly, almost daily. We can make stupid mistakes if we don't know the correct usage of the words that are commonly mistaken. 

For example 'toxin' is a word that is misused. Toxin is toxic and poison is toxic but mark poison cannot be a toxin. Many lifestyle journalists use the word 'toxin' incorrectly. Toxin is biologically produced and not  generated by artificial processes.

'Thesaurer Thursday', will be a regular feature that will appear on Twining Stream on every Thursday. It will be a treasure trove of properly understood words.

Toxin, Hapten and Antigen

  Toxin, antibody and Hapten evoke immune response but can't be used interchangeably.

toxin

Toxin is an antigenic poisonous substance that is produced within the living cells e.g., bee sting venom. Poisonous substances which are  synthesized using chemical process are not toxins, but are toxicants/toxics.

Antigen is antibody generator. It evokes the production of one or more antibodies. And the antibodies produced bind to a specific antigen. Like a key fits into a lock antigen binds to the antigen binding site of the antibody. Antigens are of two types self and non-self, self antigens are tolerated by the body.

Hapten is a molecule that attaches to a protein which acts as its carrier and illicits  immune response. The small protein which acts as the carrier is incapable of generating immune response. Hapten is incapable of acting as an antigen and thereby stimulating the production of antibodies without its association with the carrier protein.

Toxin is a fictional character in the marvel comics universe.