416
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→Glandular tissue
* Glands of the ear canal
* Glands of the ear canal
* Pericloacal glands
* Pericloacal glands
* ''Keratinocytes''
The '''Uropygial gland''' is also known as the ''preen gland''. It is a bilobed gland located dorsal to the cloaca at the end of the pygostyle. It opens through a caudally directed nipple.
The '''Uropygial gland''' is also known as the ''preen gland''. It is a bilobed gland located dorsal to the cloaca at the end of the pygostyle. It opens through a caudally directed nipple.
The uropygial gland is involved in maintaining feather condition and secretions spread by preening. It serves a waterproofing function. The secretions contain a pro-vitamin D, converted by UV light to active vitamin D. The secretions are also believed to suppress the growth of micro-organisms, serving an anti-bacterial function.
The uropygial gland is involved in maintaining feather condition and secretions spread by preening. It serves a waterproofing function. The secretions contain a pro-vitamin D, converted by UV light to active vitamin D. The secretions are also believed to suppress the growth of micro-organisms, serving an anti-bacterial function.
'''Keratinocytes''' are important in birds without a uropygial gland. Developing dermal cells (keratinocytes) undergo metamorphosis from cuboidal or squamous nature, lose organelles, produce lipids and fibrous proteins ('''keratin''') and dehydrate and lyse.
This function is unique to birds and it is suggested that the lipid production by the keratinocytes makes the entire skin an 'oil-producing' gland.
Given that birds do not have sweat or odour producing glands, it is noted that when stressed (e.g. during handling), some parrot species emit a musty odour. This appears to arise from volatile fats emitted directly onto the skin by rapidly lysing keratinocytes.
==Links==
==Links==
http://en.wikipedia.org/wiki/Feathers
http://en.wikipedia.org/wiki/Feathers