42 terms

The Eye

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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