Record Details

Gross Anatomical And Histomorphological Studies On Hypothalamo-Hypophysio-Mammary Axis Of Sheep (Ovis aries)

KrishiKosh

View Archive Info
 
 
Field Value
 
Title Gross Anatomical And Histomorphological Studies On Hypothalamo-Hypophysio-Mammary Axis Of Sheep (Ovis aries)
 
Creator Paramasivan, S
 
Contributor Ramesh, Geetha
Ushakumary, S
Balachandran, C
Kulasekar, K
 
Description The gross anatomical and histomorphological studies on the hypothalamus,
hypophysis cerebri and mammary glands were conducted on prepubertal, pubertal,
pregnant, lactating and dry age groups of Madras Red sheep. Gross biometrical
parameters of pituitary gland, mammary glands and teats were recorded for all the age
groups of sheep. Tissue pieces were collected in various fixatives for routine and special
staining techniques.
The hypothalamus of sheep was located ventral to the thalamus and bounded by
optic chiasma and mammillary body. In prepubertal, pubertal and dry animals, the
pituitary gland was irregularly triangular but in pregnant and lactating sheep the gland
appeared as oval or round structure. The length width and thickness of the pituitary gland
also showed steady increase upto lactating age groups of sheep. The length, width,
thickness and antero-posterior distance of the mammary gland showed higher values in
pregnant and lactating age groups of sheep.The paraventricular nucleus (PVN), supraoptic nucleus (SON), ventromedial
nucleus (VMN), arcuate nucleus (AN) and posterior hypothalamus (PH) were identified
in the hypothalamus of sheep in all age groups studied. The diameter of the neurons and
their nuclei in PVN was minimal during prepubertal age group and showed higher values
in pregnant and lactating sheep.
The SON and VMN comprised of small to moderate sized multipolar cells with
Nissl substance with eccentrically placed nuclei which had well-marked nucleoli. The
small neurons of the AN showed higher values of diameter during pregnant and lactating
age groups of sheep. The neurons were positive for PAS reaction and also alkaline
phosphatase activity was observed in the neurons of all the age groups studied. Electron
microscopic study revealed increased synthesis and secretory activity of neurons of
hypothalamus in lactating and pregnant sheep.
The pars distalis of the pituitary gland comprised of acidophils, basophils and
chromophobes. The number of acidophils was minimum during prepubertal age but
increased in lactating sheep and pregnant animals. The number and diameter of
acidophils reduced significantly in dry animals. The type I acidophils and type II
acidophils were identified under transmission electron microscope. Four types of
basophils were recorded. The cysts in various stages of development were clearly seen in
the pars distalis of dry animals. The pars nervosa comprised of the unmyelinated axons,
blood vessels and pituicytes. The pars tuberalis surrounded the initial part of the
infundibular stalk. A bee-hive shaped or elliptical projection of the pars intermedia called
as cone of Wulzen was noticed in the middle of the hypophysial cavity.
The gross parameters of mammary gland showed higher values for pregnant and
lactating age groups of sheep. The alveolar size was maximum in lactating sheep than
other age groups. The alveoli showed degenerative changes and the lumen became
obliterated both in the alveoli and ducts. The lumen of alveoli in the mammary glands
during pregnant and lactation ages showed positive reaction for calcium. The alkaline
phosphatase activity was seen along the basal and luminal regions of the cell lining the
alveoli. Electron microscopic study revealed that the alveolar cellular differentiation
progressed in the pregnant mammary gland.
 
Date 2016-05-27T16:21:17Z
2016-05-27T16:21:17Z
2007
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/66406
 
Language en
 
Format application/pdf
 
Publisher Tamil Nadu Veterinary and Animal Sciences University