Titlebook: Vision in Vertebrates; M. A. Ali,M. A. Klyne Book 1985 Plenum Press, New York 1985 LGN.biochemistry.brain.health.information.nervous syste

conscience

反抗者

Visual Pigments,sequences of events do not require enzymatic or metabolic energy. On the other hand, the regeneration of the visual pigment from the product of reaction is energy consuming. The photoactivation and regeneration of the visual pigment, termed the visual cycle (Wald, 1935) is illustrated in Fig. 3.1.

DAUNT

Extraocular Photoreceptors,ction by ultraviolet radiation, and to a lesser extent the degree of tanning of human skin are proportional to the number of quanta in the light which produces these effects. These processes are all mediated by photopigments. In photoreception, however, the pigments are located within specialised cells — photoreceptors.

Ischemic-Stroke

牢騷

Physiology of the Retina,t — rods and cones. Although basically of similar design, these cells are distinguishable morphologically. However, problems may arise when the retina contains only one type of photoreceptor. It may then be necessary to resort to physiological studies before proper identification is possible.

Valves

Visual Pigments,he discharges in the optic nerve there must be a light-sensitive mediating mechanism. In the vertebrate eye this is achieved by the photostimulation of the visual pigments. Rhod-opsin when photostimulated undergoes a series of spontaneous reactions which ultimately results in stable products. These

MUMP

Adaptations to Light and Dimness, this, only a narrow region of the continuum (visible light) is detectable by the eyes of living organisms. The visible light, defined in terms of human sensitivity, ranges from about 400 nm (violet) to 700 nm (red) (Fig. 5.1). To the human, the sunlight’s spectral composition appears white. This na

Heterodoxy

Adaptations to Various Modes of Life,) periods between. The lengths of these periods vary with season and latitude. Within the tropics, especially along the equator, there is practically no variation in the photoperiod (a constant light/dark period of approximately 12 hours each throughout the year) while in the polar regions there can

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