Search results
Results from the WOW.Com Content Network
Swordfish also possess an impressive visual system. The eye of a swordfish can generate heat to better cope with detecting their prey at depths of 2000 feet. [58] Certain one-celled microorganisms, the warnowiid dinoflagellates have eye-like ocelloids, with analogous structures for the lens and retina of the multi-cellular eye. [59]
The human eye is a sensory organ in the visual system that reacts to visible light allowing eyesight. Other functions include maintaining the circadian rhythm, and keeping balance. Arizona Eye Model. "A" is accommodation in diopters. The eye can be considered as a living optical device.
Visual phototransduction is the sensory transduction process of the visual system by which light is detected by photoreceptor cells (rods and cones) in the vertebrate retina.A photon is absorbed by a retinal chromophore (each bound to an opsin), which initiates a signal cascade through several intermediate cells, then through the retinal ganglion cells (RGCs) comprising the optic nerve.
The PAX6 gene locus is a transcription factor for the various genes and growth factors involved in eye formation. [1] [5] Eye morphogenesis begins with the evagination, or outgrowth, of the optic grooves or sulci. These two grooves in the neural folds transform into optic vesicles with the closure of the neural tube. [6]
The macula (/ˈmakjʊlə/) [1] or macula lutea is an oval-shaped pigmented area in the center of the retina of the human eye and in other animals. The macula in humans has a diameter of around 5.5 mm (0.22 in) and is subdivided into the umbo, foveola, foveal avascular zone, fovea, parafovea, and perifovea areas.
Two horse lenses suspended on water by cling wrap with four approximately parallel lasers directed through them. The 1 cm spaced grid indicates a near focus focal length of around 6 cm. Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its
Light from a single point of a distant object and light from a single point of a near object being brought to a focus. The accommodation reflex (or accommodation-convergence reflex) is a reflex action of the eye, in response to focusing on a near object, then looking at a distant object (and vice versa), comprising coordinated changes in vergence, lens shape (accommodation) and pupil size.
At a cellular level, there appear to be two main types of eyes, one possessed by the protostomes (molluscs, annelid worms and arthropods), the other by the deuterostomes (chordates and echinoderms). [24] The functional unit of the eye is the photoreceptor cell, which contains the opsin proteins and responds to light by initiating a nerve impulse.