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Equine Endocrine System - Horse Anatomy (view source)
Revision as of 14:19, 19 November 2012
, 14:19, 19 November 2012→Adrenal Glands
==Adrenal Glands==
==Adrenal Glands==
The adrenal glands are paired bodies lying cranial to the kidneys within the retroperitoneal space. The glands consist of two layers; the '''cortex''' and '''medulla'''.
The '''adrenal cortex''' is red to light brown in colour and is composed of three zones. These zones all produce hormones derived from cholesterol, which is abundant in the cells. From the outer to inner, the layers are:
1. Zona Glomerulosa: Secretes '''mineralocorticoids'''
2. Zona fasciculata: Secretes '''glucocorticoids'''
3. Zona Reticularis: Secretes sex steroids or '''androgens'''
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.
[[Image:Adrenal Gland Schematic..jpg|700px|small>'''Schematic Diagram of the Adrenal Gland</small>|frameless]]
==Pineal Glands==
==Pineal Glands==