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Fine Structure of the Bovine Tapetum Fibrosum
Author(s) -
Braekevelt Charlie R.
Publication year - 1986
Publication title -
anatomia, histologia, embryologia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.34
H-Index - 35
eISSN - 1439-0264
pISSN - 0340-2096
DOI - 10.1111/j.1439-0264.1986.tb00713.x
Subject(s) - tapetum , anatomy , choroid , lamella (surface anatomy) , fibril , electron microscope , chemistry , retina , materials science , biophysics , biology , optics , pollen , ecology , stamen , physics , microspore , neuroscience
Summary The fine structure of the tapetum lucidum of the domestic cow was studied by electron microscopy. In this ungulate the reflective layer is a tapetum fibrosum situated in the choroid and mainly restricted to the superior fundus. The tapetum is composed of a large array of fine extracellular collagen fibrils separated into lamellae by fibrocytes. The collagen fibrils display the normal cross‐striations of native collagen, are 0.2 μm in diameter and are arranged in a hexagonal pattern with a center‐to‐center spacing of about 0.2 μm. The diameter and spacing of these fibrils is consistent with the constructive interference of reflected light. A vascular lamella adjacent to the retinal epithelial layer contains the choriocapillaris and some irregularly arranged collagen fibrils. The tapetum is pierced by blood vessels which supply the choriocapillaris. Over the tapetum the retinal epithelium is non‐pigmented while in nontapetal regions this layer is pigmented. The choriocapillaris is not indented into the retinal epithelium as is the case in species with a tapetum cellulosum.