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Titolo:
Microscopic anatomy of the eye of the deep-diving antarctic weddell seal (Lepfonychotes weddellii)
Autore:
Welsch, U; Ramdohr, S; Riedelsheimer, B; Hebel, R; Eisert, R; Plotz, J;
Indirizzi:
Univ Munich, D-80539 Munich, Germany Univ Munich Munich Germany D-80539Univ Munich, D-80539 Munich, Germany Alfred Wegener Inst Polar & Meeresforsch, Bremerhaven, Germany Alfred Wegener Inst Polar & Meeresforsch Bremerhaven Germany n, Germany Lincoln Univ, Anim & Food Sci Div, Canterbury, New Zealand Lincoln Univ Canterbury New Zealand od Sci Div, Canterbury, New Zealand
Titolo Testata:
JOURNAL OF MORPHOLOGY
fascicolo: 2, volume: 248, anno: 2001,
pagine: 165 - 174
SICI:
0362-2525(200105)248:2<165:MAOTEO>2.0.ZU;2-Y
Fonte:
ISI
Lingua:
ENG
Soggetto:
MARINE MAMMALS; HARBOUR SEAL; BEHAVIOR; ULTRASTRUCTURE; RETINA; EATER; LIONS;
Keywords:
Weddell seal; seals; eye; accommodation; canal of Schlemm; retina; photoreceptors; area centralis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: Welsch, U Pettenkoferstr 11, D-80336 Munich, Germany Pettenkoferstr 11 Munich Germany D-80336 80336 Munich, Germany
Citazione:
U. Welsch et al., "Microscopic anatomy of the eye of the deep-diving antarctic weddell seal (Lepfonychotes weddellii)", J MORPH, 248(2), 2001, pp. 165-174

Abstract

The microscopic anatomy of the eye of the Weddell seal was studied with various light and electron microscopic methods with a view to correlating morphological findings with the biology of this seal which is adapted to the extremes of the Antarctic environment and to extreme diving excursions into the lightless depths of the sea. In the retina an area centralis was found but no fovea centralis. The densely packed photoreceptors consist exclusively of highly differentiated rods, which in primates detect light at low intensity but have rather poor image discrimination. The ganglion cells are relatively scarce, suggesting a high degree of convergence of the light-sensitive cells on the ganglion cells. The pigment epithelium is almost devoid of pigment granules. The extensive tapetum lucidum is about 400-500 mum thick and is composed of about 30 layers of specialized cells. The cornea is 650 (center) to 800-900 (periphery) mum thick. Its structure and glycosaminoglycan histochemistry correspond to that of other mammals. The iridocorneal angle is unusually deep and pervaded by an elaborate trabecular meshwork, which together with a complex canal of Schlemm can be correlated with the ability to absorb large amounts of fluid. The ciliary muscle and its antagonist, the membrane of Bruch, are poorly developed, suggesting relatively poorabilities of accommodation. The combination of a well-developed tapetum lucidum, an unpigmented pigment epithelium, well-developed rods, and a high number of rods converging on only few ganglion cells is obviously an adaptation to an extreme light sensitivity, enabling the animals to make use of the little fight available in the deep sea. J. Morphol. 248:165-174, 2001. (C) 2001 Wiley-Liss, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 12:44:41