Prenatal development of heart of sheep (Ovis aries) with special reference to conducting system
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Date
2021
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Department of Veterinary Anatomy and Histology, OUAT, Bhubaneswar
Abstract
The present study was conducted on the 12 apparent healthy foeti of non-descript sheep
of Odisha divided into three age groups viz. G-I (0-50 days), G-II (51-100 days) and G-III
(101-150 days), with 4 foeti in each group to record the detailed morphogenesis of the heart
which encompassed gross morphogenesis and morphometry, histomorphogenesis and
morphometry, histochemical development and biochemical development. The results revealed
the shape of the heart to vary from triangular to conical in the sheep foeti. The cells lining the
endocardium and epicardium became elongated from flat shape with advancing age. The
intercalated discs appeared continuous from broken lines with advancing age in the
myocardium of cardiac wall in sheep foeti. The frequency of blood vessels, connective tissue
fibres and connective tissue cells increased with age in the subendothelium, subepicardium,
myocardium, epicardium, cardiac valves and cardiac fibrous skeleton in the sheep foeti. The
average circumference, height, length and thickness of heart increased in the sheep foeti from
G-I to G-III. The cardiac conducting cells such as cells of SA node, internodal fibres, AV node,
bundle of His and purkinje fibres were noted to be larger in size than the surrounding cardiac
myocytes and had a glassy cytoplasm. The average diameter of the myocardiocytes, Purkinje
fibres, blood capillaries of cardiac walls, nucleus of the myocardiocytes and Purkinje fibres,
endothelial cells lining the internal wall of the heart and the frequency distribution of
myocardiocytes, fibroblasts, nuclei of myocardiocytes and intercalated discs and blood
capillaries in the endocardium and myocardium of heart and revealed an age dependent rise in
sheep foeti of G-I to G-III. Scanning electron microscopic studies revealed the presence of
pores among the endothelial cells and cardiac myocytes in the sheep foeti at all stages of
gestation. The PAS activity was observed in the cardiac wall, interatrial septum,
interventricular septum and cardiac vales in the sheep foeti at all stages of gestation. Occasional
mast cells and a sparse number of argentaffin cells were noted in the pectinate muscles of atria,
papillary muscles of ventricles and myocardium of interventricular septum in all the sheep
foeti. The frequency of nerve fibres increased with age in the heart wall, interatrial septum,
interventricular septum and cardiac valves in the sheep foeti. A variable degree of acid
phosphatase activity was noted in the epicardium and myocardium of heart wall in the sheep
foeti at all stages of gestation. The lipid deposition increased with advancing age in the
myocardium of cardiac wall, interatrial septum and interventricular septum in the sheep foeti.
The activities of various enzymes like creatine kinase, alkaline phosphatase, serum glutamic pyruvic transaminase and serum glutamic-oxaloacetic transaminase were high in left ventricle
than the right ventricle in the sheep foeti. Certain protein bands of specific molecular weight
appeared in the ventricular tissue at specific age of gestation in addition to a group of common
proteins which appeared in all the age of foeti used in the present study.
Description
Th-6618