Anatomy and Physiology study guide S

photoreceptor cell synaptic transmission

.... (glutamate release) is continuous in the dark and inhibited by light (more light, less glutamate release).

photoreceptor cells

.... are the main cells in the retina that engages in phototransduction (some ganglion cells are capable of phototransduction as well).

ciliary muscles

......... control the shape of the lens

pupillary reflex

ANS (parasympathetic: contract pupil; sympathetic: dilate pupil)

parasympathetic

Accommodation is controlled by the ______ division of the nervous system.

cilliary processes

Aqueous humor is secreted by the ______.

glutamate, ganglion cells

Bipolar cells that are responsive to light onset are inhibited by ..... Thus in the presence of light, bipolar cells are disinhibited and activate .....via the release of glutamate from bipolar cell axon terminals.

lateral geniculate nucleus, occipital lobe

For image-forming aspects of vision, visual information from the optic tract is relayed through the ...(LGN) of the thalamus. LGN then connects to the .... (visual cortex), which performs central processing of vision.

optic nerve

Ganglion cells axons form the ..., which partially crosses over at the optic chiasm and forms the optic tract.

suspensory ligaments

Hold the lens in place and connect it to the ciliary muscles

bipolar cells

In the retina, the specialized neurons that connect the rods and cones with the ganglion cells.

visual fields

Inputs from the left and right eyes having overlapping ....

pigmented layer (eye)

L

refracted (bent)

LIght rays are ....when they pass through the lens and the cornea.

photopsin

One of a family of visual pigments in the cones of the vertebrate eye that absorb bright, colored light.

pigmented layer

Outer layer, absorbs light and prevents its scattering, and stores vitamin A.

optic disc

Region at the back of the eye where the optic nerve meets the retina. It is the blind spot of the eye because it contains only nerve fibers, no rods or cones, and is thus insensitive to light.

horizontal cells

Retinal neurons that mediate lateral interactions between photoreceptor terminals and the dendrites of bipolar cells.

amacrine cells

Specialized retinal cells that contact both the bipolar cells and the ganglion cells, and are especially significant in inhibitory interactions within the retina.

ciliary body (eye)

Structure surrounding the lens that connects the choroid and iris. It contains ciliary muscles, which control the shape of the lens, and it secretes aqueous humor.

within

The fovea centralis lies ______ the macula lutea.

cornea

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

no

The optic disc contains ______ photoreceptors.

stereoscopic vision

The overlapping visual fields provide us with .... (depth perception).

uvea

The vascular tunic of the eye is also called the ______.

fibrous, vascular, retina

Three principal tunics (layers):

astigmatism

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

lacrimal gland, blinking, lacrimal puncta, lacrimal canaliculus, lacrimal sac, nasolacrimal duct

What is the order of structures that tears pass through?

concave (myopia), convex (hyperopia)

What type of corrective lenses are needed for myopia and hyperopia?

anterior

Which cavity of the eyeball is divided into an anterior and posterior chamber?

sclera

Which part of the eye is an attachment site for extrinsic eye muscles?

choroid

Which structure of the eye absorbs light to prevent it from scattering within the eye?

iris

a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening/ controls opening and closing of the pupil

tarsal plate

a thick fold of connective tissue that gives form and support to the eyelids

lacrimal gland

about the size and shape of an almond, supralateral depression of each orbit, produces lacrimal fluid

red cones

best detect light at 558 nm

blue cones

best detect wavelengths of light at about 420 nm

macula latea

central area of retina -yellowish pigment, filters UV light

outer segment of rods and cones

contains discs enriched in opsins.

inner segment of rods and cones

contains organelles and connects to the cell body.

posterior cavity

contains vitreous humor

Phototransduction

conversion of light energy into an electrical signal

ocular conjunctiva

covers anterior sclera (white of eye)

glaucoma

disease where fluid pressure builds up in the eye, dislocating lens

diplopia

double vision, extrinsic muscles weaker in one eye

lacrimal canaliculi

drain lacrimal fluid from eyes medially into the lacrimal sac

palpebral conjunctiva

epithelium covering inner surfaces of eyelids and outer surface of eye

hyperopia

farsightedness; eyeball is too short so near objects are blurry

lacrimal caruncle

fleshy elevation at the medial commissure; produces a whitish oily secretion

vitreous humor

gelatinous, fills posterior cavity, supports eye shape and retina

inhibitory, excitatory

glutamate is .... at the photoreceptor cell-bipolar cell synapse, and .... at the bipolar cell-ganglion cell synapse

neural layer

inner layer; composed of photoreceptors and associated neurons

neural layer

inner layer; composed of photoreceptors and associated neurons (C)

conjunctival fornix

junction of ocular and palpebral conjunctiva

lateral palpebral commissure

lateral corner of eye

macular degeneration

loss of photoreceptor cells near the fovea

green cones

maximally absorb light at 530 nm

medial palpebral commissure

medial junction of eyelids

choroid

middle, vascular layer of the eye, between the retina and the sclera

myopia

nearsightedness, eyeball too long so far objects appear blurry

emmetropia

normal refractive condition of the eye

cataract

opacities within the lens that causes milky vision

palpebral fissure

opening between eyelids

nasolacrimal duct

passageway for tears from the lacrimal sac into the nose

cornea, aqueous humor, pupil, lens, vitreous humor, retina

pathway of light

conjunctivitis

pink eye; inflammation or infection of the conjunctiva, also the outer most layer of the eye

cones

primarily located within fovea centralis respond to stimulation by bright light color recognition sharpness blue, green, and red less numerous than rods

rods

primarily located within peripheral retina dim light, night vision, cannot distinguish color more numerous than cones lacks sharpness

ciliary process

produces aqueous humor

Glaucoma

results from the blockage of aqueous humor drainage

Photoreceptors

rods and cones

tarsal glands

secretors of an oily substance; located in the eyelids

detached retina

separation of the retina from the choroid in back of the eye

lacrimal sac

structure that collects tears before emptying into the nasolacrimal duct (1)

sclera, cornea

substructures of fibrous tunic

pigmented, neural layers

substructures of retina tunic

choroid, ciliary body, iris

substructures of vascular tunic (houses blood vessels, lymph vessels, and muscles)

pupil

the adjustable opening in the center of the eye through which light enters

vascular

the conjunctiva is... and contains goblet cells

optic nerve

the nerve that carries neural impulses from the eye to the brain

rhodopsin

the pigment in rod cells that causes light sensitivity transduction of dim light most sensitive to light at 500 nm wavelength

ora serrata

the serrated boundary between the ciliary muscle and the retina

lacrimal apparatus

the structures that produce, store, and remove tears, which contain lysozyme, water, ions, antibodies

cornea

the transparent layer forming the front of the eye.

lens

the transparent structure behind the pupil that changes shape to help focus images on the retina flattens for farther objects , thickens for further objects

ganglion cells

their axons form the optic nerve

fovea centralis

tiny pit or depression in the retina that is the region of clearest vision

lacrimal puncta

two small pores that drain the lacrimal lake

aqueous humor

watery fluid in the eye, found between the cornea and the lens/ provides nutrients and oxygen to cornea and lens

anterior

what chamber is between the iris and the cornea?

sphincter pupillae

when looking at objects closer than 20 feet, the .... muscle of the iris contracts to decrease light rays passing through the edges of the lens

converge, spherical, constrict, diverge, dilate

when viewing objects that are close, the eyes .... (move medially), the lenses accommodate (become more ....), the pupils ...... When viewing objects far away, the opposite happens (eyes ...., no accommodation, ... pupils)

sclera

white of the eye/ covered by ocular conjunctiva