Adrenaline is a breakdown product of Noradrenaline. Both are produced within chromaffin cells of the adrenal medulla.
Tyrosine is the starter molecule for both. It is broken down in the cytoplasm to form DOPA, which in turn is broken down into dopamine. Dopamine is then taken up into the granules where it is broken down into noradrenaline (in the presence of the enzyme catalyst Dopamine-B-hydroxylase).
15% of the noradrenaline produced is stored for release. The rest re-enters the cytoplasm where it is further broken down into adrenaline in the presence of PEA-N-methyltransferase. It is then taken back up for storage in the granules, ready for release.
The release of both is stimulated by the sympathetic nervous system (NA released directly from sympathetic ganglia, adrenaline being released from the adrenal glands under stimulation from the sympathetic nervous system).
Adrenaline tends to act more strongly on beta receptors (e.g. lipolysis, incr. insulin secretion, incr. heart rate, incr. arteriolar dilation - therefore decr. BP)
NA tends to act more strongly at alpha receptors (e.g. decr. insulin secretion, arteriolar constriction - therefore incr. BP, sphincter contraction, sweating, pupil dilation)
Both act to increase glycogenolysis, gluconeogenesis and cardia contraction (as these are stimulated by both alpha and beta receptors)
they are both transmitters of the sympathetic nervous system - the only difference is that adrenaline is from the methylation of noradrenaline. They both act on the same receptors although with different affinities
this is true only for postganglionic fibres - transmission from pre-ganglionic to post-ganglionic, sympathetic or parasympathetic - involves acetylcholine
wow you guys know so much biology :| noones taught me any of this *decides shes going to fail*
Don't be disheartened, my, darkenergy and parts of other's posts is degree/post-A2 level requirements of knowledge - personally, I tend to go for overkill in replies, because too much information won't make someone fail - and if what I post isn't understood, or needs clarifying I would rather do it that way than have to keep adding to it. For A level I wouldn't have thought you need to know more than that the sympathetic nervous system uses NA (and adrenaline), and the parasympathetic uses ACh.
Having said that when I did A2 AQA biology we only needed to know about ACh - it could have changed in the 4 years since i did it though
/edit: god is it really 4 years, seems like yesterday
Don't be disheartened, my, darkenergy and parts of other's posts is degree/post-A2 level requirements of knowledge - personally, I tend to go for overkill in replies, because too much information won't make someone fail - and if what I post isn't understood, or needs clarifying I would rather do it that way than have to keep adding to it. For A level I wouldn't have thought you need to know more than that the sympathetic nervous system uses NA (and adrenaline), and the parasympathetic uses ACh.
Having said that when I did A2 AQA biology we only needed to know about ACh - it could have changed in the 4 years since i did it though
/edit: god is it really 4 years, seems like yesterday
I never knew that for A-level Biology... I did Edexcel which explains it. (it stands for something and excellence I believe. )
Is it that adrenaline is secreted by endocrine gland and noradrenaline is secreted by the sympathethic system? Or are they the same thing.
noradrenaline is called so because it does not have the R group that adrenaline does...it should read no-R-adrenaline...basically theres a CH3 group missing from the end of it.....
i think the synoptic actually did ask something on noradrenaline because i remember lookin at the past paper and thinking...i have never even learnt any of this....