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Adrenal Glands - Anatomy & Physiology (view source)
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==Adrenal Glands==
==Adrenal Glands==
3. zona reticularis
3. zona reticularis
All these zones produce hormones derived from cholesterol, which is abundant in the cells. The '''adrenal cortex''' represents 80-90% of the adrenal gland.
The '''adrenal medulla''' is primarily involved in the production of catecholamines; epinephrine and norepinephrine. In fetal life, the adrenal medulla plays a role in the autonomic nervous system. The medulla acts as a sympathetic ganglion with the postganglionic cells lacking axons. Through sympathetic preganglionic fiber stimulation, the medullary cells secrete catecholamines. The adrenal medulla represents only 10-20% of the adrenal gland.
The '''adrenal medulla''' is primarily involved in the production of catecholamines; epinephrine and norepinephrine. In fetal life, the adrenal medulla plays a role in the autonomic nervous system. The medulla acts as a sympathetic ganglion with the postganglionic cells lacking axons. Through sympathetic preganglionic fiber stimulation, the medullary cells secrete catecholamines. The adrenal medulla represents only 10-20% of the adrenal gland.
<gallery>
<gallery>
Image:Histology of the Adrenal Glands..jpg|<small>'''Histological section of the Adrenal Gland. (RVC 2008)</small>
Image:Histology of the Adrenal Glands..jpg|<small>'''Histological section of the Adrenal Gland, from the [[Endocrine Histology resource|Histology of the Endocrine system tutorial]]</small>
Image:Histology of the Adrenal Glands showing zones..jpg|<small>'''Histological section of the Adrenal Gland Cortical zones. (RVC 2008)</small>
Image:Histology of the Adrenal Glands showing zones..jpg|<small>'''Histological section of the Adrenal Gland Cortical zones, from the [[Endocrine Histology resource|Histology of the Endocrine system tutorial]]</small>
Image:Histology of the Adrenal Glands Medulla..jpg|<small>'''Histological section of the Adrenal Gland showing Medulla and Zona Reticularis (RVC 2008)</small>
Image:Histology of the Adrenal Glands Medulla..jpg|<small>'''Histological section of the Adrenal Gland showing Medulla and Zona Reticularis, from the [[Endocrine Histology resource|Histology of the Endocrine system tutorial]]</small>
</gallery>
</gallery>
==Functional anatomy==
[[Image:Normal adrenal cortex.jpg|right|thumb|125px|<small><center>'''Normal Adrenal Cortex'''. Courtesy of A. Jefferies</center></small>]]
The adrenal glands are essential to life.
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.
*'''Cortex''': Secretes a variety of steroid hormones derived from ''cholesterol''.
**''Zona glomerulosa'': Secretes '''Aldosterone'''. Concerned with electrolyte and fluid homeostasis.
**''Zona Fasciculata'': Secretes '''Glucocorticoids'''. Controls metabolism of lipid, protein and carbohydrate.
**''Zona Reticularis'': Produces '''Sex hormones'''. Supplements gonadal sex hormone secretion.
*'''Medulla''': Embryologically similar origin to the sympathetic nervous system. Secretes ''catecholamine hormones'' E.g. Adrenaline, noradrenaline.<br>
Secretion from the medulla is directly controlled by the sympathetic nervous
system, allowing a rapid response. In contrast, the secretions from the cortex are controlled by the hormones ACTH and other circulating hormones.
As with any endocrine gland there are two main types of pathology:
*Insufficiency leading to [[Hypoadrenocorticism|'''Addisons disease''']].
*Excess leading to [[Hyperadrenocorticism|'''Cushings disease''']].
{{Template:Learning
|powerpoints = [[Endocrine Histology resource|Histology of the Endocrine system]]
|OVAM = [http://www.onlineveterinaryanatomy.net/content/ovine-adrenal-gland-histology Ovine Adrenal Gland Histology 1]<br>[http://www.onlineveterinaryanatomy.net/content/ovine-adrenal-gland-histology-zona-fasiculate-and-zona-glomerulosa Ovine Adrenal Gland Histology 2]
|Vetstream = [https://www.vetstream.com/canis/search?s=adrenals Adrenal diseases]
}}
==Webinars==
<rss max="10" highlight="none">https://www.thewebinarvet.com/endocrinology/webinars/feed</rss>
[[Category:Endocrine System - Anatomy & Physiology]]
[[Category:Endocrine System - Anatomy & Physiology]]
[[Category:A&P Done]]
[[Category:A&P Done]]