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The dark blue, teal, and gold tapetum lucidum from the eye of a cow Retina of a mongrel dog with strong tapetal reflex. The tapetum lucidum (Latin for 'bright tapestry, coverlet'; / t ə ˈ p iː t əm ˈ l uː s ɪ d əm / tə-PEE-təm LOO-sih-dəm; pl.: tapeta lucida) [1] is a layer of tissue in the eye of many vertebrates and some other animals.
The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina. [1] It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil.
The head of a mantis showing the black pseudopupil in its compound eyes The eye of a mantis shrimp has three regions, each with its own pseudopupil.. In the compound eye of invertebrates such as insects and crustaceans, the pseudopupil appears as a dark spot which moves across the eye as the animal is rotated. [1]
In the mammalian eye, light enters the pupil and is focused on the retina by the lens. Light-sensitive nerve cells called rods (for brightness), cones (for color) and non-imaging ipRGC ( intrinsically photosensitive retinal ganglion cells ) react to the light.
A slit pupil can indicate the common multifocal system, while a circular pupil usually specifies a monofocal system. When using a circular form, the pupil will constrict under bright light, increasing the f-number, and will dilate when dark in order to decrease the depth of focus. [49] Note that a focusing method is not a requirement.
At the centre of the iris is the pupil, the variable circular area through which the light passes into the eye. [4] [19] Hummingbirds are amongst the many birds with two foveae. The retina is a relatively smooth curved multi-layered structure containing the photosensitive rod and cone cells with the associated neurons and blood vessels. The ...
The tapetum lucidum reflecting green in the pupils of a cat Cat eyes stand out. Cats have a tapetum lucidum, which is a reflective layer behind the retina that sends light that passes through the retina back into the eye. [1] They also have a high number of rods in their retina that are sensitive to dim light. [2]
The animal of Pupilla muscorum is small, elliptical, dark with lighter sides and foot, upper tentacles not very long, lower tentacles very short. [3] Extant populations of P. muscorum are practically identical in shape to their ancestors, indicating that they have tracked their ecological niches over time. [6] The height of the shell is 3.0–4 ...