Muscle “islands” in the tunica media of the goat thoracic aorta
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Date
2009Author
Ogeng'o, Julius A
Malek, A A K
Kiama, S G
Olabu, B O
Type
ArticleLanguage
enMetadata
Show full item recordAbstract
Muscle islands in tunica media of the aorta may influence its mechanical properties and disease distribution. This
study aimed to elucidate their, hitherto undescribed, characteristics in the goat thoracic aorta. Twenty four healthy
male domestic goats (capra hircus) aged 6 – 24 months were used in the study. The animals were euthanized
with sodium pentabarbitone. Samples were taken from the ascending, arch and descending thoracic aorta.
7 μ paraffin embedded sections stained with Mason’s Trichrome and Weigert Resorcin Fuchsin/Van Gieson
stains were examined by light microscopy for general organization of tunica media. Transmission electron
microscopic examination of ultrathin sections stained with uranyl acetate and counterstained with lead citrate
was done to study ultrastructure of the muscle islands. Fluorescent histochemical demonstration of adrenergic
nerves was done by the sucrose-potassium phosphate-glyoxilic acid (SPG) method. Muscle “islands” were
observed to interrupt elastic lamellae of the outer zone of tunica media in proximal aortic segments. These
islands were preferentially vascularized and innervated. They comprised interconnected contractile smooth
muscle cells linked to connective tissue fibres. These islands probably constitute an auxillary pump which
supplements the windkessel function of the elastic lamellae, regulate blood flow and also strengthen the aortic
wall.
Citation
Braz. J. Morphol. Sci., 2009, vol. 26, no. 3-4, p. 171-175Publisher
Department of Human Anatomy, University of Nairobi