Which of the following layer of the eyeball is characterized as the vascular layer?

choroid

This is the white fibrous outer layer that covers the outer posterior portion of the eyeball and serves to protect the inner parts of the eyeball

sclera

This is a transparent, thin, mucous tissue layer that protects the anterior surface of the white portion of the eyeball

conjunctiva

This fluid or gel occupies the anterior segment of the eyeball

aqueous humor

Which is not considered an “accessory structure” of the eye?

retina

A sty (or stye) is caused by

an infection of the sebaceous ciliary glands

This structure secretes a fluid that keeps the eyelids from sticking to each other

Tarsal (Meibomian) gland

This is the transparent portion of the sclera through which light passes

cornea

The main function of this structure is to regulate the amount of light entering the eyeball through the pupil

iris

Which of the following apply to the choroid layer of the eyeball?

contains melanocytes producing melanin, absorbs stray light within the eyeball, is found between the sclera and retina, and is referred to as part of the vascular tunic

This region of the eye is between the lens and the retina

vitreous/posterior segment

Aqueous humor drains from the anterior chamber into the

schleral venous sinus

Intraocular pressure is primarily due to

an imbalance in the amount of the aqueous humor being produced and being drained

Blockage of the scleral venous sinus is likely to result in

glaucoma

Most of the light refraction in human vision occurs at the

cornea

How many extrinsic eye muscles are responsible for moving one eye?

6

The point of greatest visual acuity (resolution) is the:

fovea centralis

During accommodation for near vision:

the ciliary muscles contract due to parasympathetic innervation

In humans, both eyes focus forward on only one set of objects. This is called

binocular vision

Constriction of the pupil is brought about by contraction of the

circular muscle of the iris via parasympathetic innervation

The photopigment in the rods and cones is imbedded in the

membrane folds or discs of the outer segment of the photoreceptor cells

The most common type of color blindness is:

red-green color blindness

The lens is made of layers of transparent layered proteins called:

crystallins

Which of the following conditions is not related to lens pathology?

glaucoma

Which of the following photoreceptors are functional during bright light situations?

cones

Inflamed blood vessels in this layer show up as bloodshot eyes:

conjunctiva

After light is absorbed in the rods:

Na+/Ca++ channels close and less inhibitory neurotransmitter is released at the synapse with the bipolar cells

When entering a dark room on a sunny day, it takes some time to be able to see because

it takes time for the retina

The bipolar neurons associated with the sensory light receptors are found in the:

neural layer of the retina

In daylight, rods contribute little to vision because

the rhodopsin is bleached as fast as it is regenerated

Which cranial nerve is made up of axons of the ganglion cells of the retina?

II

The first step in visual transduction is

the absorption of light by the rhodopsin photopigments

Binocular vision

provides for depth perception

As the axons of the ganglion cells extend from the retina to the brain, nerve fibers

from the medial half of each retina cross to reach the opposite visual cortex

As a result of an injury, a person loses all sight in the left eye, but has no trouble seeing with the right eye. The injury has probably severed the

left optic nerve

Blue light has both a higher frequency (more oscillations per unit time) and a shorter wavelength than red light.

True

The stacked disc membranes of rods are found in the outer segment of rods.

True

Presbyopia involves a loss in lens elasticity in older people that increases the near point of vision.

True

The differential activation of more than one type of cone is responsible for distinguishing different colors and hues.

True

The area of sharpest vision, called the fovea centralis, consists of all rods.

False

The pupil enlarges when the eye focuses on close objects.

False

The circular smooth muscle of the iris opens the pupil and the radial smooth muscle of the iris closes the pupil.

False

The "light absorbing form" of retinal is the trans form.

False

Processes involving bleaching and regeneration of the photopigments account for much, but not all, of the sensitivity
changes during light and dark adaptation.

True

The nasolacrimal sac empties into the nasal cavity.

True

Diabetes is one of the most common causes of blindness in the U.S.

True

Red light has longer wavelengths than blue light.

True

In light adaptation, the visual system adjusts to brighter environments by increasing sensitivity.

False

In convergence, the both eyeballs move laterally so they are both directed toward the object being viewed.

False

There are more cones in the human retina than rods.

False

Trans-retinal is the form that readily binds to opsin.

False

Isomerization is the chemical term that describes the conversion of cis-retinal to trans-retinal.

True

The blind spot of each eye is where the optic nerve penetrates the eyeball.

True

The aqueous humor is fluid-like and the vitreous humor is more gel-like.

True

Retinal is a derivative of Vitamin K.

False

The deepest layer of the neural retina is formed by the axons of the ganglion neurons.

False

Which diagram represents the
uncorrected emmetropic eye?

A

Which diagram represents
nearsightedness before being corrected?

B

Which diagram demonstrated
farsightedness before it has been
corrected?

D

Which diagram is being corrected with a
concave lens?

C

When viewing an object that is close to your eyes, which member of the following pair, are required for proper image formation on the retina?

a. Decreased curvature of the lens b. Increased curvature of the lens

b. Increased curvature of the lens

When viewing an object that is close to your eyes, which member of the following pair, are required for proper image formation on the retina?

a. Contraction of the ciliary muscle b. Relaxation of the ciliary muscle

a. contraction of the ciliary muscle

When viewing an object that is close to your eyes, which member of the following pair, are required for proper image formation on the retina?

a. Divergence of the eyeballs b. Convergence of the eyeballs

b. convergence of the eyeballs

When viewing an object that is close to your eyes, which member of the following pair, are required for proper image formation on the retina?

a Dilation of the pupil b. Constriction of the pupil

b. constriction of the pupil

With age-related macular degeneration, the (central, peripheral) vision is progressively lost.

central

There are (two, three, four) different cone photopigments in the retina.

three

Upon the absorption of light, receptor potentials in the rods and cones (increase, decrease) the release of neurotransmitter. This then induces depolarization in the bipolar cells.

decrease

When photopigments absorb light, the light (increases, decreases) neurotransmitter release thus turning (on, off) the release of inhibitory neurotransmitter so that the excited bipolar cells stimulate the ganglion cells to initiate action potentials in their axons.

decrease, off

All photopigments contain a glycoprotein called _______________, and a derivative of vitamin A called ___________________________.

opsin, retinal

This structure produces the aqueous humor - ____________________ _____________, while this
structure drains the aqueous humor and returns it to the blood - ____________________ __________
______________________.

ciliary processes, scleral venous sinus

______________________________ is the increase in the curvature of the lens.

Accomodation

This surface region on the retina that has no rods or cones is known as the _____________ ___________.
Since the image is missing from this region, it is known as the ______________ _________________.

optic disc, blind spot

Place the letters preceding each structure in the correct order of light passage into the eye:

A. anterior chamber; B. pupil; C. posterior segment; D. cornea; E. vitreous body; F. lens; G. retina

D. cornea; A. anterior chamber; B. pupil; F. lens; C. posterior segment; E. vitreous body; G. retina

Place the letters preceding each structure in the correct order of nerve impulse passage starting with light absorption.

A. axons of ganglion cells; B. rods and cones; C. optic nerve; D. optic chiasma; E. bipolar cells; F. optic tract

B. rods and cones; E. bipolar cells; A. axons of ganglion cells; F. optic tract; D. optic chiasma; C. optic nerve

Light passes through various layers of the retina. Starting with the vitreous chamber, place the letters preceding each of the structures through which light passes before absorption.

A. vitreous chamber; B. layer of ganglionic cells; C. layer containing the outer segments of rods and cones embedded in the pigment layer; D. layer containing axons of ganglion cells; E. layer containing the cell bodies of rods and cones; F. layer of bipolar cells

A. vitreous chamber; D. layer containing axons of ganglion cells; B. layer of ganglionic cells; F. layer of bipolar cells; E. layer containing cell bodies of rods and cones; C. layer containing the outer segments of rods and cones embedded in the pigment layer