Adrenal Medulla Function & Disorder PDF

ADRENAL MEDULLA FUCNTION &DISORRDER Medulla Adrenal medulla The adrenal medulla is at the center of each adrenal gland, and is surrounded by the adrenal cortex. The chromaffin cells of the medulla are the body's main source of the catecholamines adrenaline and noradrenaline, released by the medu...

ADRENAL MEDULLA FUCNTION &DISORRDER Medulla Adrenal medulla The adrenal medulla is at the center of each adrenal gland, and is surrounded by the adrenal cortex. The chromaffin cells of the medulla are the body's main source of the catecholamines adrenaline and noradrenaline, released by the medulla. Approximately 20% noradrenaline (norepinephrine) and 80%.adrenaline (epinephrine) are secreted here Biosynthesis and Storage of Catecholamines NE and EPI biosynthesis begins with the sequential conversion of phenylalanine substrates. All reactions take place in the cytoplasm, except for the production of NE, which occurs within lipid vesicles (vesicle monoamine transporters) (VMAT)or outer.mitochondrial membranes. In sympathetic neurons, cytoplasmic dopamine is sequestered into vesicles, converted into NE, and stored until nerve.stimulation causes its release In medulla chromaffin cells, NE can passively  diffuse into the cytosol. In the cytosol, NE is converted into EPI by a cortisol-dependent enzyme called phenylethanolamine N-.methyltransferase (PNMT) :Function of adrenal medulla The adrenal medulla produced Adrenaline and noradrenaline are catecholamines, water-soluble compounds that have a structure made of.a catechol group and an amine group The adrenal glands are responsible for most of the adrenaline that circulates in the body, but only for a small amount of circulating noradrenaline These hormones are released by the ,adrenal medulla Adrenaline and noradrenaline act at.adrenoreceptors throughout the body :Their function include An increase (control) in blood pressure, -.metabolism, and heart rate.Fight or flight response - Constriction of blood vessels in many -.parts of the body :Disorder of adrenal Medulla Catecholamines Hyperactivity Pheochromocytoma Causes of Catecholamines Hyperactivity Autonomic dysfunction  Panic attack (emotions)  Stress responses: hypoglycemia, injury,  infarction, infection, psychosis, and seizures Drugs: such as decongestants, appetite  ,suppressors, stimulants Foods: such as beer, red wine, soy sauce, and .smoked Pheochromocytoma (catecholamine-producing .tumor) :Pheochromocytoma Is a rare tumor of adrenal gland tissue, it results  in the release of too much catecholamines (epinephrine and norepinephrine) hormones that control heart rate, metabolism, and blood.pressure :Symptoms include Headaches (severe)  Excess sweeting  Tachycardia and palpitations  Anxiety, and tremors  Pain in the lower chest or upper abdomen  Nausea  Weight loss  :Diagnosis of Pheochromocytoma  The best test for diagnosing  :Pheochromocytoma Is measurement of fractionated -1  metanephrines and catecholamines in a 24-.hour collection Measuring both total plasma-2  catecholamines (NE and EPI) and urine metanephrines is the most sensitive.screening profile Plasma metanephrines, measured by-3 high-performance liquid chromatography or RIA, are the most.specific and sensitive diagnostic test For localization of -4 Pheochromocytoma (mass), either CT (without dye) or MRI of the abdomen.and adrenal glands is performed THANKS