Deck 32: Vision

Question 1

"Bleaching" refe rs to the conversion of 11 cis retinal to all trans retinal that reduces the lgiht absorption of the visual pigment and causes unresponsiveness to light. Recovery from bleaching is part of the function of

A) Bip ola r c ells
B) M itra l ce lls
C) H or izon tal c ells
D) G an glio n c ells
E) Re tina l pig m en ted epit he lial cells

Answer 1

E

Question 2

O n c en ter ga ng lion ce lls a re m os t ac tive wh en the rec ep tive field

A) Perim eter is lit, but center is dark
B) Perim eter and center are d ark
C) Pe rim eter is da rk, bu t cen ter is lit
D) Pe rim ete r an d c en ter are lit
E) W hen inhibitor centers are inhibited

Answer 2

C

Question 3

Neurons in the left optic nerve carry visual information from

A) The left temporal retina and right nasal retina
B) The left nasal retina and right temporal retina
C) The left temporal retina and left nasal retina
D) The right temporal retina and right nasal retina
E) The left temporal retina and right temporal retina

Answer 3

A

Question 4

Which of the following does NOT describe retinal rod cells?

A) They have a higher sensitivity than cones
B) They are used for dim light
C) They saturate in bright light
D) They hav e long er ou ter se gm ents
E) They give rise to h igh visu al acuity

Question 5

O f th e fo llow ing , the ea rlies t ev en t in p ho totr an sd uc tion is

A) Ex ch an ge of G T P f or G D P o n th e a lph a s ub un it of tra ns du cin
B) Activation of guanylate cyclase
C) Activation of guanylate cyclase phosphodiesterase
D) Closing the Na+ channel
E) Conversion of 11 cis retinal to all trans retinal

Question 6

The optic nerve makes initial synaptic contact in the

A) Thalamus
B) Hypothalamus
C) Superior colliculus
D) Lateral geniculate nucleus
E) Sensory association area

Question 7

Contraction of the ciliary body

A) Releases tension on the suspensory ligaments that causes the lens to become rounder
B) Pulls on the suspensory ligaments to thin the lens
C) Pulls on the suspensory ligaments that then causes the lens to become rounder
D) Releases tension on the suspensory ligaments that cause the lens to become thinner
E) Limits light input into the eyes

Question 8

The "blind spot" in the visual field is due to light falling on the

A) Op tic disk w here there are no pho torec epto rs
B) Macula lutea where there are only rods
C) Macula lutea where there are only cones
D) Orra se rrata where there are no photorecep tors
E) Fovea w here there are no photorecep tors

Question 9

"O n c en ter " bip ola r c ells

A) Are in hib ited by g luta m ate re leas ed by p ho tore cep tor c ells
B) Are dep olarized by glutam ate
C) Ex cite o n ce nte r ga ng lion cells
D) C on ve rg e o nto m itra l an d h or izon tal c ells
E) A and C are correct

Question 10

Most of the refractive power of the eye is due to the

A) Lens
B) Cornea
C) Aqueous humor
D) Vitreous humor
E) None of the above

Question 11

Sympathetic stimulation of the iris causes

A) Opening of the iris by stimulating the dilator muscles
B) Closing of the iris by stimulating the dilator muscles
C) N o e ffe ct o n th e iris
D) Opening of the iris by stimulating the sphincter muscles
E) Closing of the iris by stimulating the sphincter muscles

Question 12

Cones are most highly concentrated in the

A) Fovea
B) Or ra se rrata
C) Optic disk
D) Linea alba
E) Macula lutea

Question 13

At rest, the refractive power of the eye is about 63 Diopters. The amount of refractive power due to the lens is about

A) 63 D
B) 43 D
C) 10 D
D) 20 D
E) 73 D

Question 14

The fun ction o f the iris is to

A) Relax the lens
B) Thin the lens
C) Make the lens rounder
D) Con trol the apertu re of the eye
E) Give eyes their color

Question 15

The shape of the eyeball is maintained by the

A) Aqueous humor
B) Vitreous humor
C) Sclera
D) Uvea
E) Ocular muscles

Question 16

Focusing on objects at the near point involves

A) C on tra ctio n o f th e c iliary m us cle
B) R ela xa tion of t he cilia ry m us cle
C) Convergence
D) C on tra ctio n o f th e la ter al re ctu s m us cle
E) Both A and C

Question 17

The three layers of the outer eyeball include all of the following EXCEPT the

A) Sclera
B) Retina
C) Uvea
D) Conjunctiva
E) All o f th e a bo ve are laye rs of t he eye ba ll

Question 18

Retinal cells that produce action potentials include

A) Cones
B) Rods
C) Bip ola r C ells
D) Ga ng lion cells
E) Both A and C

Question 19

The pathway for detailed information involves

A) Pa rvo cellu lar ga ng lion cells
B) M ag no ce llula r ga ng lion ce lls
C) Intr ins ica lly ph oto re sp on siv e g an glio n c ells
D) R od bip ola r c ells
E) Layers 1 and 2 of the lateral geniculate nucleus