Photreceptors

• light sensing cells in the eye

• highly vascular membrane that constitutes the psoterior three-fourths of the vascular tunic
• provides oxygen and nutrients to the retina and sclera

• doughnut-shaped ring of tissue that encircles the lens 
• composed of a rck network of blood vessels mixed with lesser amounts of fibrous tissue and smooth muscle fibers

• extend between the lens and the ciliary body

• arises from the anterior edge of the ciliary body
• colored part of the eye
• thin, pigmented disc composed of fibrous tissue and smooth muscle fibers
• sits between the cornea and the lens

• image snesing layer of the eyeball
• origin of visual pathway

• small pit
• small and highly sensative part of the retina responsible for central vision

• clear, watery fluid secreted by the ciliary body

• a duct that encircles the eye at the base of the ciliary body

• neurons in the retinal surface
• gather at the optic disc to form the optic nerve

• neurons with two extensions
• one extension= dedrites= receives sinals from the deepest neural layer, the rods and cones
• other extension= the axon= transmits signals to ganglion cells