Editing Adrenal glands (section)

== '''Catecholamines''' ==

* '''Synthesis''' (medulla)
** Hydroxylation of tyrosine      leads to dopamine
** Beta-hydroxylation of      dopamine forms noradrenaline
** Phenylethanolamine      N-methyltransferase then produces adrenaline in chromaffin cells
** Sympathetic stimulation of      the medulla results in release of stored catecholamines
**
* '''Function'''
** Tissue response is mediated      by alpha and beta-adrenergic receptors
** Alpha-adrenergic receptors      have greater affinity for NA - vasoconstriction in skin, GIT
** Beta-adrenegic is more      adrenaline - myocardium to increase HR and contracitlity, smooth muscle      relaxation in uterus, bronchi, and skeletal muscle arterioles
* '''Metabolism'''
** Catecholamines are potent      and short-acting compounds, with a plasma half-life of 1 minute
** NA and adrenaline are      inactivated by one or both of the enzymes monoamine oxidase and      catechol-0-methyltransferase to produce metanephrine and normetanephrine,      which can be detected in plasma and urine at more stable levels than the      fluctuations in actual catecholamines. The final product is      vanillymandelic acid, which is excreted in the urine.

[[Category:Anatomy]]