منابع مشابه
The ageing photoreceptor.
With age many retinal neurons are lost. In humans the rod photoreceptor population in the perimacular region is subject to approximately 30% loss over life. Those that remain have been reported to suffer from extensive convolutions and localized swellings of their outer segments abnormally increasing their disc content and outer segment length. Here we examine quantitatively age-related changes...
متن کاملThe Limit of Photoreceptor Sensitivity
Detection threshold in cone photoreceptors requires the simultaneous absorption of several photons because single photon photocurrent is small in amplitude and does not exceed intrinsic fluctuations in the outer segment dark current (dark noise). To understand the mechanisms that limit light sensitivity, we characterized the molecular origin of dark noise in intact, isolated bass single cones. ...
متن کاملThe photoreceptor process in vision.
In this paper I should like to review briefly the present status of the chemistry of visual excitation, specifically in vertebrates; and then to discuss connections between these processes and visual physiology and pa thology. Light initiates a nervous excitation in the outer segments of the rods and cones which, transmitted from one neurone to another to centers in the brain, ends in exciting...
متن کاملPhotoreceptor Structures
The eyes of three eye mutants of Drosophila melanogaster were fixed and thin sections studied for its structural detail in the electron microscope. Each ommatidium was found to have seven retinula cells with an equal number of rhabdomeres (visual units). The rhabdomeres average 1.2 micro in diameter and 60 micro in length. Each rhabdomere consists of osmium-fixed dense bands averaging 120 A in ...
متن کاملPhotoreceptor Biotechnology
Plant photoreceptors influence or control almost all aspects of plant metabolism, growth and development. Only the extent and timing of this control is variable (see other chapters in this volume). Many agriculturally relevant traits are either heavily influenced or completely controlled by photoreceptors. These include seed germination, circadian timing, seedling architecture, bud dormancy, le...
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ژورنال
عنوان ژورنال: Eye
سال: 1998
ISSN: 0950-222X,1476-5454
DOI: 10.1038/eye.1998.136