Biomaterial Database

Some reflective properties of the tapetum lucidum of the cat's eye. 1971

J A Coles

1. Observation of the fresh, isolated tapetum of the cat with a low-power microscope showed it to be composed of multilayer reflectors (domains) each being less than 6 mum in diameter. It is concluded that these are subdivisions of the intracellular bundles of rodlets seen in electron micrographs.2. Apparatus was devised for illuminating a single domain with a pencil of white light and observing the colour and direction of the reflected light.3. Those domains which lie near the vitreal surface of the tapetum tend to reflect blue light and deeper ones reflect longer wave-lengths; this is attributed to differences in the layer spacings of the domains.4. Each domain has a set of reflecting planes lying within 15 degrees of the general plane of the tapetal surface. In addition, many domains have surfaces inclined to these at angles greater than 20 degrees which also can reflect visible light.5. The mechanism of reflexion is discussed in relation to the latticelike structure of the domain.6. It is suggested that under some conditions the nature of the tapetum may lead to significant local variations in the spectral sensitivity of the visual system.

UI	MeSH Term	Description	Entries
D008027	Light	That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.	Light, Visible,Photoradiation,Radiation, Visible,Visible Radiation,Photoradiations,Radiations, Visible,Visible Light,Visible Radiations
D008961	Models, Structural	A representation, generally small in scale, to show the structure, construction, or appearance of something. (From Random House Unabridged Dictionary, 2d ed)	Model, Structural,Structural Model,Structural Models
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D002829	Choroid	The thin, highly vascular membrane covering most of the posterior of the eye between the RETINA and SCLERA.	Choriocapillaris,Haller Layer,Haller's Layer,Sattler Layer,Sattler's Layer,Choroids
D003118	Color Perception	Mental processing of chromatic signals (COLOR VISION) from the eye by the VISUAL CORTEX where they are converted into symbolic representations. Color perception involves numerous neurons, and is influenced not only by the distribution of wavelengths from the viewed object, but also by its background color and brightness contrast at its boundary.	Color Perceptions,Perception, Color,Perceptions, Color
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia