Eyes and vision
Terms in this set (15)
is a sensory organ, analogous to a camera. It focuses visual images on the retina. light stimuli.
is a layer of the eye that contains sensory receptors that respond to light stimuli. Visual pathway is optic nerves to optic chiasma to optic tract to lateral geniculate nucleus of thalamus to visual cortex. Medial retinal fibers cross over in chiasma, lateral fibers do not
the occipital lobe of the brain interprets signals relating to shape, color, and movement & spatial organization
origin oculomotor (III), trochlear (IV) and abducens (VI) cranial nerves coordinate eye movements and changes in lens shape and pupil size
bending of light rays as they pass obliquely from one medium into another of different optical density (property of transparent material which is a measure of speed of light through it)
Accommodation of lens
change in refractive power due to change from moderately convex (distant vision) to very convex (higher refraction for near vision). Ciliary muscle is controlled mainly by parasympathetic nerves.
Depth of focus
distance an object can move & remain in focus, arrowing diameter of the pupil increases depth of focus, also prevents light from passing through the periphery of the lens where curvature is greater. Circular smooth muscle of iris constricts pupil, autonomic response.
Three processes involved in focusing
refraction, accommodation of lens, and depth of focus
light sensitive coat of the eye. retinal layers from deeper to surface contacting vitreous humor
axons of ganglionic cells
center of macula where layer 3 - 7 are pushed aside allowing light to reach the cones unimpeded, on visual axis, increases visual acuity or resolution
blind spot area of retina where optic nerve exits, no rods or cones
rod & cones
integral protein of disc membrane
vitamin A derivative. light absorbing portion, 2 isomers cis and trans