Adrenal medulla - wikipedia Adrenal medulla Adrenal medulla Medulla labeled at bottom right. Details Precursor Neural crest Artery superior suprarenal artery, middle suprarenal artery, Inferior suprarenal artery Vein suprarenal veins Nerve celiac plexus, renal plexus Lymph lumbar glands Identifiers MeSH D000313, D019439 TA A11. 5.00. 008 FMA 15633 Anatomical terminology ( edit on Wikidata ) Medullary part of the adrenal gland ( on the pointer ). The adrenal medulla ( Latin : medulla glandulae suprarenalis ) is part of the adrenal gland. It is located at the center of the gland, being surrounded by the adrenal cortex. It is the innermost part of the adrenal gland, consisting of cells that secrete epinephrine ( adrenaline ), norepinephrine ( noradrenaline ), and a small amount of dopamine in response to stimulation by sympathetic preganglionic neurons. Contents 1 Basic 2 Function 3 Origin 4 Pathology 5 See also 6 References 7 External links Basic The adrenal medulla consists of irregularly shaped cells grouped around blood vessels. These cells are intimately connected with the sympathetic division of the autonomic nervous system ( ANS ). In fact, these adrenal medullary cells are modified postganglionic neurons, and preganglionic autonomic nerve fibers lead to them directly from the central nervous system. The adrenal medulla therefore affects available energy, heart rate, and metabolism. Recent research indicates that the adrenal medulla is under the control of the sensory and motor cortex rather than centres associated with the conscious mind as previously thought. Function Rather than releasing a neurotransmitter, the cells of the adrenal medulla secrete hormones. The adrenal medulla is the principal site of the conversion of the amino acid tyrosine into the catecholamines ; epinephrine, norepinephrine, and dopamine. Because the ANS, specifically the sympathetic division, exerts direct control over the chromaffin cells the hormone release can occur rather quickly. In response to stressors such as exercise or imminent danger, medullary cells release the catecholamines adrenaline and noradrenaline into the blood. Adrenaline composes about 85 % of the released catecholamines, and noradrenaline the other 15 %. Notable effects of adrenaline and noradrenaline include increased heart rate and blood pressure, blood vessel constriction in the skin and gastrointestinal tract, smooth muscle ( bronchiole and capillary ) dilation, and increased metabolism, all of which are characteristic of the fight - or - flight response. Release of catecholamines is stimulated by nerve impulses, and receptors for catecholamines are widely distributed throughout the body. Origin Medullary cells are derived from the embryonic neural crest and, as such, are simply modified neurons. In particular, they are modified postganglionic cells of the autonomic nervous system that have lost their axons and dendrites, receiving innervation from corresponding preganglionic fibers. The cells form clusters around large blood vessels. As a cluster of neuron cell bodies, the adrenal medulla is considered a ganglion of the sympathetic nervous system. Pathology Neoplasms include : Pheochromocytoma ( most common ), a catecholamine - secreting tumor of the adrenal medulla Neuroblastoma, a neuroendocrine tumor of any neural crest tissue of the sympathetic nervous system Ganglioneuroma, a tumor in the nerve cells of the peripheral nervous system The adrenal medulla may be poorly formed or absent in cases of absent adrenal gland. The deficiency in circulating catecholamines is mildly symptomatic due to compensation by the autonomous nervous system, except in episodes of hypoglycemia where glycogenolysis can not be stimulated by circulating epinephrine. In dopamine beta hydroxylase deficiency, the entire body can not efficiently produce epinephrine and norepinephrine from dopamine, this results in severe dysautonomia but most crucially due to autonomous nervous system failure which requires epinephrine and norepinephrine as neurotransmitters, dopamine being used in this pathology as an inadequate substitute. See also Adrenal gland History of catecholamine research References Jump up ^ Dum, Richard ( 2016 ). `` Motor, cognitive, and affective areas of the cerebral cortex influence the adrenal medulla ''. Proceedings of the National Academy of Sciences of the United States of America. 113 : 9922 -- 9927. doi : 10.1073 / pnas. 1605044113. PMC 5024624. Jump up ^ Introduction to Autonomics, Part 2 - Page 5 of 12 anatomy module at med.umich.edu ^ Jump up to : Fung, M.M. ; Viveros, O.H. ; O'Connor, D.T. ( 16 November 2007 ). `` Diseases of the adrenal medulla ''. Acta Physiologica. 192 ( 2 ) : 325 -- 335. doi : 10.1111 / j. 1748 - 1716.2007. 01809. x. PMC 2576282. PMID 18021328. Jump up ^ Robertson, D ; Haile, V ; Perry, SE ; Robertson, RM ; Phillips JA, 3rd ; Biaggioni, I ( July 1991 ). `` Dopamine beta - hydroxylase deficiency. A genetic disorder of cardiovascular regulation ''. Hypertension. 18 ( 1 ) : 1 -- 8. doi : 10.1161 / 01. hyp. 18.1. 1. PMID 1677640. External links Anatomy photo : 40 : 04 - 0202 at the SUNY Downstate Medical Center - `` Posterior Abdominal Wall : Blood Supply to the Suprarenal Glands '' Anatomy Atlases - Microscopic Anatomy, plate 15.292 - `` Adrenal Gland '' Anatomy of the endocrine system Pituitary gland Anterior Pars intermedia Pars tuberalis Pars distalis Acidophil cell Somatotropic cell Prolactin cell Somatomammotrophic cell Basophil cell Corticotropic cell Gonadotropic cell Thyrotropic cell Chromophobe cell Posterior Pars nervosa Median eminence Stalk Pituicyte Herring bodies Thyroid Follicular cell Parafollicular cell Parathyroid gland Chief cell Oxyphil cell Adrenal gland Cortex Zona glomerulosa Zona fasciculata Zona reticularis Medulla Chromaffin cell Gonads Testicle Leydig cell Sertoli cell Ovary Theca interna Granulosa cell Corpus luteum Islets of pancreas Alpha cell Beta cell PP cell Delta cell Epsilon cell Pineal gland Pinealocyte Corpora arenacea Other Enteroendocrine cell Paraganglia Organ of Zuckerkandl Placenta Development List of human endocrine organs and actions Retrieved from `` https://en.wikipedia.org/w/index.php?title=Adrenal_medulla&oldid=840762813 '' Categories : Adrenal gland Sympathetic nervous system Epinephrine Hidden categories : Pages with unresolved properties Articles containing Latin - language text Talk Contents About Wikipedia Aragonés Български Čeština Dansk Deutsch Español 한국어 Italiano עברית Limburgs Magyar 日本 語 Polski Português Suomi Українська 粵語 9 more Edit links This page was last edited on 12 May 2018, at 00 : 41. 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Question: when does the body secrete epinephrine and norepinephrine
Answer: In response to stressors such as exercise or imminent danger