photoreception (eyes)

Question 1

ocelli

Answer 1

a distinct feature of planarians, that detect light and send impulses to the anterior ganglia

Question 2

pigmented cells

Answer 2

shade the receptors medially

Question 3

photoreceptor neurons

Answer 3

located at the center of each ocellus detect light and send impulses to anterior ganglia

Question 4

rhopalia

Answer 4

sensory structures each containing two forms of reception: a statocyst and ocellus

Question 5

ommatidia

Answer 5

optical units

Question 6

corneal lens

Answer 6

a crystalline cone that funnels light onto multiple photoreceptors

Question 7

optic nerve

Answer 7

usually cut so that only small stump remains on the posterior surface

Question 8

sclera

Answer 8

white surface of the eye (outermost layer)

Question 9

cornea

Answer 9

cloudy surface over the pupil and iris (if alive would be clear)

Question 10

iris

Answer 10

colored portion in front of the ciliary body

Question 11

pupil

Answer 11

opening surrounded by iris

Question 12

lens

Answer 12

a hard, pinkish or yellowish sphere

Question 13

vitreous body

Answer 13

a gelatinous mass filling most interior

Question 14

retina

Answer 14

thin, white membrane on back (posterior) wall containing the rods and cones

Question 15

optic disk

Answer 15

the portion of the retina where neurons gather to form the optic nerve

Question 16

pigmented choroid coat

Answer 16

dark layer behind retina that absorbs stray light

Question 17

tapetum lucidum

Answer 17

an iridescent coating on the surface of the choroid coat that reflects this light so it passes through the retina a second time to increase light sensitivity