Anatomical and Histological Study of some Integumentary
Glands of Local Iraqi Breed of Sheep (Ovis aris)
Abdulla Aaid Hadi AL-Bishtue
Summary
This research included anatomical and histological study of some
integumentary glands of local Iraqi sheep and specimen were taken
during autumn season from four modified integumentary glands
(interdigital gland, inguinal gland, infraorbital gland, subcaudal gland)
The anatomical result revealed that the mean in this study can be
summarized as follow: the means weight, length, width, thickness of
interdigital gland and it's duct length in this sheep were 1.18g, 17.81,
7.60, 7.20 and 26.06mm respectively. When we compared the
biometric characters of interdigital gland in fore limbs with hind limbs,
it was revealed that the glands on fore limbs are larger than the hind
limb's glands
The histological structure was showed that integumentary glands
composed of the epidermis and dermis but it consist third layer in
interdigital glands characterized by presence of fibrous capsule beside
the other two layers.
-I-
The histological study result revealed that epidermis was thin in
most integumentary glands and composed of four secondary layers
including from lower to upper: stratum basale, stratum spinosum,
stratum granulosum, stratum corneum but consist thick epidermis was
in subcaudal gland characterized by presence of stratum lucidum
beside the other fourth layers. The study revealed a marked variation
in thickness epidermis was noticed in the subcaudal gland 82.18 µm,
on the contrary the epidermis of infraorbital gland was found to be
thinnest 40.33 µm.
In general, it was also observed that was a direct relation between
the whole thickness of epidermis and of stratum corneum in all of the
studied regions.
The histological study showed that the dermis composed of two
essential layers :the superficial thin papillary layer which is located
directly under the base membrane and it's included dermal papillae, in
areas very thin skin, such as the interdigital glands, inguinal glands,
infraorbital glands the dermal papillae were flattened and some times
were absent, the subcaudal glands had dermal papilla characterized by
branches and therefore termed compound
papilla and deep thick
reticular layer which consists mainly of closely packed thick collagen
bundles. The highest thickness of dermis was observed in the
subcaudal glands which reach 2178.6 µm, but it is reduced markedly
in the infraorbital glands to1109.67 µm, the thickness of the other
regions ranging between those two extremes.
- II -
The study revealed that there were a number of skin appendages
including wool follicles, skin glands, sebaceous and sweat glands.
wool follicles in the interdigital glands were considered as compound
types in which there were more than one wool fiber emerged from
one pore on the skin surface. The follicles were arranged as groups
consist mainly of three follicles (Trio), in addition to (Dio) and (Mono)
arrangement. The simple hair follicles were observed in the
infraorbital glands,inguinal glands,subcaudal glands .
Hair density varies in the different integumentary glands being:
12.8/mm2 in the interdigital glands, 1.3/mm2 in inguinal glands,
1.4/mm2 in infraorbital glands, 2/mm2 in subcaudal glands .
Branched glands were a prominent in infraorbital glands and
subcaudal glands .the sebaceous glands are type of simple alveolar
holocrine in interdigital gland and inguinal glands. They were large in
size in the infraorbital glands and subcaudal gland, than interdigital
glands, but they were smaller in size in inguinal glands. The sebaceous
glands emptied directly on to the skin surface in interdigital glands and
inguinal glands whereas in the infraorbital glands and
subcaudal
glands they opened into the hair follicles via pilo sebaceous canal.
All sweat gland of the skin of integumentary glands were of
apocrine type. The level of extension of sweat gland vary according
to different integumentary glands, similarly the gland density differs
in different regions: the dermis of the inguinal and interdigital glands
exhibited high gland density, then subcaudal gland while the skin of
- III -
the infraorbital glands showed low gland density. The sweat gland
were most numerous in the region of the inguinal glands in which
the columnar cells had apical projection s which extended into lumens
of the glands in the region of the infraorbital glands, the sweat glands
were large and saccular, with cuboidal epithelium.
- IV -