Quiz R

what causes conjunctivitis?

- irritants - infectious agents

which are true of conjunctiva? - its does not cover the cornea - it does not contain nerve endings - it is vascular - it contains goblet cells

- it does not cover the cornea - it is vascular - it contains goblet cells

The sclera ___________. - provides for eye shape - is made of loose connective tissue - is made of dense connective tissue - allows light to enter the eye

- provides for eye shape - is made of dense connective tissue

place the structures of the eye in order from superficial to deep. start with the outermost structure first: - photoreceptors - choroid - bipolar cells - horizontal cells

1. choroid 2. photoreceptors 3. horizontal cells 4. bipolar cells

Place the layers of the eye in order from superficial to deep - retina - fibrous tunic - vascular tunic

1. fibrous tunic 2. vascular tunic 3. retina

Order these structures in the order that tears travel through them: - lacrimal sac - lacrimal puncta - lacrimal canaliculus - nasolacrimal duct

1. lacrimal puncta 2. lacrimal canaliculus 3. lacrimal sac 4. nasolacrimal duct

Each eye has ___ lacrimal puncta

2

the process is called the bleaching reaction because rhodopsin goes from a ___________ color to _________.

Bluish-purple; colorless

which may result in symptoms such as reduced field of vision, dim vision and/or halos around lights?

Glaucoma

What chamber is between the iris and cornea?

anterior chamber

aqueous humor is secreted into the __________ chamber before traveling to the ____________ chamber of the eye

anterior; posterior

what disorder is caused by unequal curvatures of the lens and cornea?

astigmatism

During the dark current, the ________ cells are inhibited, so the brain does not perceive light.

bipolar

In the light, ______________ cells are no longer inhibited and therefore release the neurotransmitter glutamate.

bipolar

during the dark current, the __________ cells are inhibited, so the brain does not perceive light

bipolar

what structure is filled with pigment from melanocytes?

choroid

prior to being stimulated by light, the retinal portion of rhodopsin is in a bent twisted shape called ___________ - retinal

cis

what type of photoreceptors detect color?

cones

the primary function of the _____________ is to prevent large objects from contacting the eye

eyelashes

hyperopia

farsightedness

the lens is ________ when we are viewing far away objects

flattened

the vitreous body is also called the vitreous ____________.

humor

Where are photoreceptors located?

in the neural layer of the retina

the ___________ segment of the photoreceptors connect directly to the cell body

inner

the majority of the optic tract axons extend to the thalamus, specifically to the __________.

lateral geniculate nucleus

cataracts are a disorder of the __________.

lens

lacrimal fluid prevents bacterial infection because it contains an antibacterial enzyme called ____________.

lysozyme

myopia

nearsightedness

emmetropia

normal vision

the __________ segment of each photoreceptor is composed of hundreds of discs containing photopigments that are capable of absorbing light energy

outer

eyelids are also called

palpebrae

the eyelids are joined at the medial and lateral _____________ commisures or _______________

palpebral; canthi

the process by which photoreceptors become activated when the photopigments are altered by light entering the eye is ____________.

phototransduction

An aging person would need to start wearing reading glasses if they suffer from ___________.

presbyopia

the black hole in the eye is called the _________ and it is surrounded by the colorful _________.

pupil; iris

Light rays are ____________ when they pass through the lens and the cornea.

refracted

The ciliary muscles are made of __________ muscle.

smooth

where is the lacrimal gland located?

superior and lateral to the eye

reflexive movements of the head, eyes and neck are coordinated by the __________.

superior colliculi

true or false: in cones, the bleaching reaction occurs as cis-retinal transforms to trans-retinal

true

true or false: in cones, the bleaching reaction occurs as cis-retinal transforms to trans-retinal.

true

true or false: the primary purpose of the eyebrows is to keep sweat out of the eyes.

true

in the eye, the ___________ humor is gelatinous

vitreous

The junction of the palpebral and ocular conjunctiva is called the ___________

conjunctival fornix

the regeneration of __________, in cones occurs much more quickly than the regeneration of ___________ in rods; therefore, cone cells are not as negatively affected by bright light as rods.

photopsin; rhodopsin

What structure makes up the posterior 5/6 of the fibrous tunic?

sclera

a detached retina is caused by a separation between which two layers? - pigmented layer of the retina - neural layer of the retina - rods and cones - axons of ganglion cells

- pigmented layer of the retina - neural layer of the retina

place the structures of CN II in order from anterior to posterior: - optic tract - optic chiasm - optic nerve

1. optic nerve 2. optic chiasm 3. optic tract

as we adjust to low light, our __________ become nonfunctional and it may take _____________ for rhodopsin to become regenerated sufficiently so that you can see well in low-light conditions

cones; 20-30 minutes

the sphincter pupillae _____________ the pupil

constricts

when light hits the eye, the pupil ___________ in bright light or ___________ in dim light.

contracts; dilates

A ______________ shaped lens is used to treat hyperopia and a _______________ shaped lens is used to treat myopia.

convex; concave

The limbus is the junction between the sclera and the __________.

cornea

when you go from a bright light environment to a dark environment, you have a slow sensitivity to low light levels. this is called _____________ ______________

dark adaptation

when elevated levels of cGMP are present, Na+ channels in the photoreceptor membrane are kept open and Na+ enters the photoreceptor. This is called the _______________ _______________.

dark current

light rays are refracted or bent when they pass through two media of different _____________.

densities

when the bipolar cells release their neurotransmitter, the ____________ cells propagate a nerve signal along the __________ nerve.

ganglion; optic

the fovea centralis lies __________ the macula lutea

within

what disease causes fluid build up in the eye, dislocating the lens?

glaucoma

as a consequence of the dark current, __________ channels in the photoreceptor open

glutamate

when rhodopsin is split by light stimulation, the calcium and sodium channels are also closed and this blocks the release of the neurotransmitter called __________.

glutamate

rods are essentially nonfunctional in bright light because __________.

in bright light, rhodopsin will bleach as fast as it is reformed

the suspensory ligaments connect the ___________ capsule to the ciliary muscles

lens

the process by which your eyes adjust from low light to bright light conditions is ___________.

light adaptation

a lack of photoreceptors in this structure creates a "blind spot"

optic disc

the cis-retinal, in the process of regeneration, is transported back to the ___________ where it associates with the opsin and reforms the ______________.

rod; rhodopsin

which layer of the eye contains the blood and lymph vessels?

vascular tunic

optic tracts ultimately are directed to the primary visual cortex in the __________ lobe.

occipital

order these structures from superficial to deep. start with the outermost structure first: - choroid - neural layer of retina - sclera - pigmented layer of retina

1. sclera 2. choroid 3. pigmented layer of retina 4. neural layer of retina