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Fibrous tunic

outer coat of the eyeball

The fibrous tunic is composed of:

1. posterior choroid
2. anterior ciliary body
3. iris

The vascular tunic (posterior choroid, anterior ciliary body and iris) are collectively called:

The Uveal Tract

Choroid carries:

blood vessels for the eyeball
contains large anounts of pigment (preventing internal reflection of light)

Ciliary body

a thickened structure containing smmoth muscle

Ciliary body muscles serve to:

change the sape of the lens
allowing changes in focal distance of the eye

The iris contains:

pigment responsible for the color of the eye

The hole in the iris is the :

pupil

The pupil permits:

light to enter the eye

Contraction of the radial muscle:

dialates the pupil

Contraction of the circular muscle:

constricts the pupil

Radial muscles and circular muscles regulate:

the amount of light entering the eye

The nervous tunic is the:

retina

The retina is the:

most innermost tunic of the eye

The retina translates:

light wabes into neural impulses

The retina contains:

several layers of nerve cells and their processes

There are two types of receptors in the retina:

rods
cones

Rods are for:

vision in dim light

Cones are for:

daytime or color vision

Cones are most densly concentrated in:

the central fovea ( a small depression in the center of the macula lutea)

The macula lutea or yellow spot is:

in the central part of the retina

The fovea is the area of:

sharpest vision because of the highest concentration of cones

Rods are absent in the:

fovea and macula

Rods increase in density toward the:

periphery of the retina

The optic disk is where the:

optic nerve exits the eye

The optic disks is the:

weak spot of the eye (blind spot)

The optic disk is a blind spot because:

it does not contain photoreceptors and light focused on it cannot be detected.

The aqueous humor is the:

fluid filling the anterior chamber of the eyeball

The aqueous humor maintains:

intraocular pressure
provides nourishment
maintains the shape of the eyeball

The vitreous humor maintains:

the spherical shape of the eye
supports the inner structures

The vitreous humor fills the:

posterior chamber of the eye

The vitreous humor is a:

jellylike substance that fills the posterior chamber of the eye and maintains the spherical shape of the eyeball

The vitreous humor and the adequous humor are:

transparent allowing light to pass through the eye to the retina.

The lens is:

a transparent biconvex crystaline body enclosed in an elastic capsule held by supensory ligiaments

The shape of the lens changes to:

focus the image

The eyeball is protected from the external world by the:

eyelid

The eyelid contains a:

thin protective layer of epeithelium (the conjunctiva)

A thin protective layer of epethelium:

the conjunctiva

The eyelashes protect the eye from:

forein particles

The lacrimal gland produces a secretion called:

tears

Tears contain:

lysozyme and muramidase

Tears destroy:

pathogens

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