Physiology: Eye And Ear

Front 1

__________ of the eye are those that are notdirectly related the sense of vision, but facilitate the physiologyof the eyeballs.

__________ shade the eyes from sunlight and to preventperspiration from reaching the eyes.

Back 1

accessory structures

eyebrows

Front 2

_________ protect the eyes from foreign objects (e.g. dust particles) and to prevent desiccation (drying) of the eyes by lubricating fluid.

___________ is a mucous membrane on the inner lining of eyelids, which produces lubricating and cleansing fluid for the surface of eye.

Back 2

eyelids

conjuctiva

Front 3

_______ is an exocrine gland that secretes a dilute saline solutioncalled tears for moistening the eyes.

_______ contain mucus, antibodiesand antibacterial enzymes that protect the eye from infections. Emotionaltears also contain enzymes that seem to help reduce stress levels

Back 3

lacrimal gland

tears

Front 4

The wall of the eyeball consists of 3 layers of tissue:

Back 4

fiborous tunic, vascular tunic, sensory tunic

Front 5

______ is the outermost layer, made of fibrous connective tissue withminimal blood vessels. - contains 2 regions: __________ (a white area that extends from theback of the eye toward the front) and ________ ( a transparenttissue in the front for allowing light to enter the eyeball).

Back 5

fiborous tunic, sclera, cornea

Front 6

________ is also called ______- middle layer, made of thin fibrous connective tissue that contains numerous blood vessels (capillaries).

It contains ______, a pigmented membrane in the back toprovide nutrition and to absorb light and the _______, which regulates theamount of light entering the eye by constriction or dilation

Back 6

vascular tunic, uvea

choroids, iris

Front 7

In addition to the choroids and iris, the vascular tunic also includes specialized structures such as the ______, which regulates the shape of lens and the ________, which attaches the ciliary body to the lens.

It includes the ______, another transparent tissue that bendsthe light entering the eye, and _____ an opening created by theactions of the iris where a large pupil is caused by a dilated iris,while a small pupil is created by a constricted iris.

Back 7

ciliary body, suspensory ligaments

lens, pupil

Front 8

Another name for the sensory tunic is: _______. It is the innermost layer, made of specialized nerve tissue. It contains 2 layers of tissue: an outer pigmented layer (which absorbslight and stores vitamin A) and an inner neural layer (that detects lightusing photoreceptors and sends nerve impulses to the occipital lobe ofcerebrum through the optic nerves.

Back 8

retina

Front 9

2 types of photoreceptors are found on the neural layer:_______ (detect tones of visual images) and _______ (detect colors). Thesesensory cells, after being stimulated by visual sensations, send nerveimpulses through the ______ (Nerve II) to the occipital lobes of______.

Back 9

rods, cones, optic nerve, cerebrum

Front 10

look at slide on desktop

Back 10

see other side

Front 11

Pathway of light

Back 11

Cornea --> Aqueous humor --> Lens --> Vitreous humor --> Retina.

Front 12

The eye is like a camera. The eye's diaphragm is the ______, which changes______ aperture, regulating the amount of light entering

The ________ change lens curvature for sharp focusing; in acamera, the lens moves back and forth

Back 12

iris, pupil

ciliary muscles

Front 13

Light rays passing throughthe transparent media ofdifferent densities are bentin _______. The densenessand curvature of the mediumdetermines the degree ofrefraction. Refraction is necessary toform a small – sized invertedimage on the retina(refractory media is thecornea and lens).  The lens must thicken tofocus on close objects.

Back 13

refraction

Front 14

________: As the distant object moves closer, the imagemoves behind the retina to keep the image sharply on the retina,the lens accommodates.

With age, the _____ hardens.

Back 14

accommodation

lens

Front 15

In close vision: ciliary muscles ______, lens ligaments_______, and lens becomes _____ (more _______)

In distance vision, ciliary muscles _____, lens ligaments(suspensory) _______, lens becomes less ______/ more _______

Back 15

contract, relax, rounder/ more convex

relax, contract, convex/ more concave

Front 16

During accommodation, the iris also______ to narrow the pupil, permitting increased depth offocus. For very close objects __________ move theeyeball inward (converge) to keep sharp focus.

The movement of each eye – ball is controlledby six eye muscles that allow the eyes to follow a movingobject. This is called _______.

Back 16

constricts, external eye muscles

convergence

Front 17

Innervation and Function:

Superior rectus

Inferior rectus

Medial rectus

Back 17

oculomotor - rotates eye up and in

oculomotor - rotates eye down and in

oculomotor - rotates eye inward

Front 18

Innervation and function:

lateral rectus

superior oblique

inferior oblique

Back 18

abducens: rotates eye out

trochlear: rotates eye down and out

rotates eye up and out

Front 19

The retina contains _____ and _____ – photoreceptor neurons thatsynapse with bipolar cells.  Rods are responsible for ______ vision in relatively dim light.  Cones provide________ vision and function in day light.

Back 19

rods, cones, colorless, color

Front 20

A light sensitive pigment in rods called ______ decomposes in the presence of light and triggers a complex series of reactions that initiate nerve impulses on the optic nerve.

3 sets of cones (_____, ____, _____), provide color vision. Each setcontains a different light – sensitive pigment, and each set issensitive to a different wave length of light. The color perceiveddepends on which set or sets of cones are stimulated.

Back 20

rhodopsin

red, green, blue

Front 21

The _________ is in the center of the retina and only contains ______, while the peripheral retina contains both rods and cones. Every cone is associated with only 1 ___ cell, which is only associated with 1 _____ cell. Visual acuity is high in the center of the retina as a result, but light sensitivity is low compared to the peripheral retina.

Back 21

retinal fovea centralis, cones

bipolar cell, ganglion

Front 22

The ____ half of the visual field is projected is projected to the left half of the retina of each eye. The left half of the left retina sends fibers to the left lateral________ of the _____. The left half of the Right retina also sends fibers to the leftlateral geniculate body. This is because these fibers decussate inthe ______.

Back 22

right

geniculate body of the thalamus

optic chiasma

Front 23

The left lateralgeniculate bodythus receives inputfrom the _____ half ofthe retina of botheyes, correspondingto the right half ofthe visual field, theright lateralgeniculate receivesinformation aboutthe _____ half of thevisual field.

Back 23

left, left

Front 24

_________ form the optic nerve fibers which converge inthe _______ where they exit the eye forming the optic nerve. The _____ of each eye (medial fibers) decussate at the opticchiasma, the ________ travel on the same side (ipsilateral).

Back 24

ganglion cells, optic disc, inner fibers, temporal

Front 25

The direct crossed fibers then synapse in the geniculate body and arecalled ______.

Back 25

optic tracts

Front 26

A small number of fibers synapse in the ___________ and control pupillary reflexes. From the lateral genticulate body a diverging bundle of fibers (opticradiation) terminate in the _________ where vision reachesconsciousness, (primary visual cortex).

Back 26

superior quadrigeminal bodies, occipital lobe

Front 27

___________ provides perception ofdistance and depth. It occurs because of theformation of two slightly different retinalimages that the brain superimposes andintercepts as one image in three dimensions.

Back 27

Stereoscopic vision