Vision test study 1

A pigment synthesized from vitamin A is A) retinal. B) opsin. C) rhodopsin. D) transducin. E) cGMP.

A

A ray of light entering the eye will encounter these structures in which order? A) conjunctiva → cornea → aqueous humor → lens → vitreous body → retina → choroid B) vitreous body → retina → choroids → aqueous humor → lens → conjunctiva → cornea C) cornea → aqueous humor → vitreous body → lens → conjunctiva → choroids → retina D) conjunctiva → cornea → lens → aqueous humor → vitreous body → retina → choroid E) cornea → aqueous humor → conjunctiva → lens → vitreous body → retina → choroid

A

A sudden increase of light into the eye would cause A) contraction of the sphincter pupillary muscles. B) contraction of the radial pupillary muscles. C) conversion of 11-trans to 11-cis retinal. D) a decrease in the size of the pupil. E) parasympathetic stimulation to the pupil.

A

The ________ covers most of the exposed surface of the eye. A) conjunctiva B) cornea C) iris D) anterior chamber E) canthus

A

The optic disc is a blind spot because A) there are no photoreceptors in that area. B) the retina lacks nerves in the optic disc . C) humans are unable to focus light on that area of the retina. D) the vitreous body is too thick in this area for the passage of light. E) the fovea prevents light from striking the optic disc.

A

The space between the cornea and the iris is the A) anterior chamber. B) posterior chamber. C) canal of Schlemm. D) aqueous humor. E) pupil.

A

An elongate outer segment containing membranous discs and a narrow connecting stalk that attaches the outer segment to the inner segment describes A) a bipolar cell. B) a photoreceptor. C) a ganglion cell. D) an amacrine cell. E) a horizontal cell.

B

During accommodation, the ciliary muscle ________ causing the ciliary body to move ________ and apply ________ tension on the lens. A) relaxes; forward; more B) contracts; forward; less C) contracts; back; more D) relaxes; inward; less E) contracts; back; less

B

In the human eye, most refraction occurs when light passes through the A) iris. B) cornea. C) lens. D) aqueous humor. E) vitreous humor.

B

The cornea is part of the A) iris. B) fibrous tunic. C) neural tunic. D) uvea. E) choroid.

B

The transparent portion of the fibrous tunic is the A) conjunctiva. B) cornea. C) iris. D) pupil. E) canthus.

B

The vitreous body A) fills the posterior chamber. B) helps to stabilize the eye and give physical support to the retina. C) is replaced at the rate of 20 percent per year until middle age. D) circulates through the pupil. E) holds the retina against the lens for proper refraction.

B

What structure changes the shape of the lens for far and near vision? A) aqueous humor B) ciliary body C) iris D) extrinsic eye muscles E) None, because the lens is rigid.

B

Which of the following description applies to the term myopia? A) farsightedness B) nearsightedness C) normal vision D) astigmatism E) age-related decline in accommodation

B

An area of the retina that contains only cones and is the site of sharpest vision is the A) outer segment. B) inner segment. C) fovea. D) optic disc. E) tapetum lucidum.

C

Having to adjust to a dark room after walking in from bright light is because A) the breakdown of rhodopsin to opsin occurs slowly. B) the lens requires time to accommodate dim light. C) rods exposed to strong light need time to regenerate rhodopsin. D) rhodopsin does not function in dim light. E) only cones function in dim light.

C

Pupillary muscle groups are controlled by the ANS. Parasympathetic activation causes pupillary ________, and sympathetic activation causes ________. A) dilation; constriction B) dilation; dilation C) constriction; dilation D) constriction; constriction E) vasoconstriction; vasoconstriction

C

The ciliary muscle contracts to A) control the amount of light reaching the retina. B) adjust the shape of the lens for distant vision. C) adjust the shape of the lens for near vision. D) control the production of aqueous humor. E) adjust the shape of the cornea and vitreous.

C

The first step in the process of photoreception is A) the bleaching of rods. B) the bleaching of cones. C) absorption of a photon by a visual pigment. D) inhibition of the sodium pumps. E) release of neurotransmitter.

C

The human lens focuses light on the photoreceptor cells by A) moving up and down. B) moving in and out. C) changing shape. D) opening and closing. E) dilating and constricting.

C

The opening in the iris through which light passes is the A) conjunctiva. B) cornea. C) pupil. D) anterior chamber. E) posterior chamber.

C

The part of the eye that determines eye color is the A) conjunctiva. B) cornea. C) iris. D) pupil. E) canal of Schlemm.

C

The shape of the lens is controlled by the A) pupillary sphincter muscles. B) pupillary radial muscles. C) ciliary muscles. D) iris. E) cornea.

C

Visual pigments are derivatives of the compound A) retinal. B) opsin. C) rhodopsin. D) transducin. E) cGMP.

C

Where are the visual pigments located in the rods and cones? A) in the inner segment of photoreceptors B) in mitochondria located in the outer segment C) inside membrane discs stacked in the outer segment D) inside a photosensitive nucleus E) sandwiched in the cell membrane of the photoreceptors

C

Which of the following descriptions best matches the term aqueous humor? A) gelatinous fluid that fills anterior chamber B) secreted in bright light C) excessive production may lead to glaucoma D) converts to vitreous humor with age E) provides the liquid component of lacrimal secretions

C

During accommodation, the ciliary muscle ________ and the suspensory ligaments become ________ which, in turn, cause the lens to become ________. A) contracts; loose; flat B) relaxes; loose; flat C) contracts; tight; round D) contracts; loose; round E) relaxes; tight; flat

D

What structure regulates the amount of light that passes to the photoreceptors of the eye? A) vitreous body B) cornea C) ciliary muscle D) iris E) lens

D

When a rod is stimulated by light, A) the plasma membrane becomes hyperpolarized. B) the retinal changes from the 11-cis to the 11-trans form. C) less neurotransmitter is released. D) cGMP decreases and sodium channels close. E) All of the answers are correct.

E

Which of the following is true about rhodopsin? A) called visual purple B) is bleached during photoreception C) is the visual pigment in rods D) consists of opsin + retinal E) All of the answers are correct.

E