4
votes
Can catecholamines degrade back into tyrosine, or, is synthesis irreversible? (in human body)
A glance at the relevant BioCyc entry tells us that each reaction in the catecholamine biosynthesis pathway is irreversible. The standard free energy change of each reaction—again from BioCyc—is given ...
- 1,297
4
votes
what is meta-sympathetic nervous system?
As @mgkrebbs says, metasympathetic nervous system is still a matter of debate and is not fully accepted in the scientific world due to lack of research and evidence.
Metasympathetic nervous system, ...
- 14.1k
4
votes
Accepted
Can stress and arousal be independent?
Stress response has 2 main components:
Quick response, within minutes, is by the Sympathomedullary Pathway (SAM): hypothalamus > sympathetic nervous system > release of adrenaline and noradrenaline ...
- 8,049
4
votes
Accepted
What are these two nerves running parallel to the spine called?
From this closeup image, you can see there is more than one nerve on each side that is parallel to the spine.
Source: imgur.com
First, they are the right and left sympathetic trunk that run from the ...
- 8,049
3
votes
What does sympathetic and parasympathetic 'tone' mean?
Short answer
Parasympathetic tone is not necessarily mediated by tonic firing.
Background
Nice question! I think part of the confusion stems from terminology. Let's start with some definitions first.
...
- 52.3k
3
votes
Accepted
what is meta-sympathetic nervous system?
The concept of a metasympathetic part of the autonomic nervous system (distinct from the sympathetic and parasympathetic parts) seems to be an idea discussed almost exclusively in the Russian ...
- 9,024
3
votes
Accepted
What is the difference between a dermatome and a sensory neurone?
This is just a confusion of English.
"Supplied" is a bit of a weird term to use, I agree, due to the direction of information flow, but feel free to substitute in just "connected to&...
- 44k
2
votes
Accepted
Voluntary actions of Autonomic Nervous System
I have no idea what the author has in mind, but their statement is wrong from the beginning: somatic motor activity is not always voluntary. Reflexes are a good and obvious example.
"Fight or flight" ...
- 44k
2
votes
Accepted
Where are interneurons in Autonomic Nervous System?
It sort of depends on your definition of interneuron. Many school-level textbooks suggest that any neuron that has neurons both pre and post synaptically are interneurons. Therefore both the ...
- 939
2
votes
Why should we preceed neostigmine by atropine in tubocurarine toxicity?
Tubocurarine is a non-depolarising neuromuscular blocking aqgent, that is, it acts as a competetive antagonist of Acetyl Choline at the Nicotinic receptors.(Toxicity/Effect: $-N$)
Atropine is a ...
- 4,669
2
votes
Why do typical acetylcholinesterase inhibitors (like carbamates) have a greater parasympathetic effect than a sympathetic effect?
We were taught that ganglionic receptors have very high thresholds. So we need a very high concentration of the drug to produce the sympathetic effects. We even solved a hypothetical problem in class, ...
- 3,667
1
vote
Are "sympathetic nerves" the same as "cardiopulmonary splanchnic" nerves?
You might consider cross-posting to SE Medical sciences who know more about this stuff.
I think that they are simply using a more general term than other authors. In the same way, most people call ...
- 9,112
1
vote
Accepted
What does it mean to say that the sympathetic nervous system is organized for diffuse activity?
"Mobilize" in this context means to:
to release (something stored in the organism) for bodily use
Merriam-Webster
"Diffuse" means "spread out": it doesn't say anything about whether the effect is ...
- 44k
1
vote
Can catecholamines degrade back into tyrosine, or, is synthesis irreversible? (in human body)
I do believe it's irreversible. When catecholamines have done their duty, they are degraded by COMT and MAO into products that are excreted in the urine.
I'll make an example out drugs that are MAO ...
- 77
1
vote
Are the sympathetic and parasympathetic nervous systems exact opposites?
The Autonomic Nervous System is composed of the sympathetic and parasympathetic nervous systems. Each are dominant under different conditions - both are always active but one is dominant.
An important ...
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