[[Image:Normal adrenal cortex.jpg|right|thumb|125px|<small><center>'''Normal Adrenal Cortex'''. Courtesy of A. Jefferies</center></small>]]
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The adrenal glands are essential to life.
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They are closely applied to the cranial poles of each kidney. Consists of a cortex and medulla, each having different embryological origin. In some lower animals the two components actually exist as separate endcrine glands.
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*'''Cortex''': Secretes a variety of steroid hormones derived from ''cholesterol''.
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**''Zona glomerulosa'': Secretes '''Aldosterone'''. Concerned with electrolyte and fluid homeostasis.
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**''Zona Fasciculata'': Secretes '''Glucocorticoids'''. Controls metabolism of lipid, protein and carbohydrate.
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**''Zona Reticularis'': Produces '''Sex hormones'''. Supplements gonadal sex hormone secretion.
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*'''Medulla''': Embryologically similar origin to the sympathetic nervous system. Secretes ''catecholamine hormones'' E.g. Adrenaline, noradrenaline.<br>
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Secretion from the medulla is directly controlled by the sympathetic nervous
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system, allowing a rapid response. In contrast, the secretions from the cortex are controlled by the hormones ACTH and other circulating hormones.
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As with any endocrine gland there are two main types of pathology:
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*Insufficiency leading to [[Hypoadrenocorticism|'''Addisons disease''']].
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*Excess leading to [[Hyperadrenocorticism|'''Cushings disease''']].
[[Category:Endocrine System - Anatomy & Physiology]]
[[Category:Endocrine System - Anatomy & Physiology]]