The Eye Flashcards
___, one of the special senses, relies on a very complex receptor apparatus: the eye.
Vision
____ depends on a variety of positioning and focusing mechanisms to form an image in the correct spot on the light-sensitive receptor cells inside the eye.
These mechanisms involve muscles, lenses, and other structures that are all a part of the visual apparatus.
The complexity of structure allows for complexity of function.
Vision
The visual image perceived by humans has the qualities of
resolution, brightness, color, and depth.
The ____ and its accessory structures provide the structural apparatus required for processing and receiving visual images.
human eye
What are lacrimal apparatus ?
Lacrimal gland
Nasolacrimal duct
Exocrine “tear” gland in the superior lateral corner of the orbit
Lacrimal gland
Duct in the inferior medial corner of the orbit, drains tears from lacrimal canals toward the nasal cavity
Nasolacrimal duct
Extrinsic eye muscle
Superior, inferior, medial, lateral
Rectus muscles. (four)
Extrinsic eye muscle
Superior, inferior
Oblique muscles (two)
Thin, transparent mucous membrane adhering to the anterior surface of the eye and lining the eyelids
Conjunctiva
Layers of the eyeball
Fibrous layer
Vascular layer
Inner layer
Fibrous layer (outer coat)
The ___ is the anterior, transparent portion. The ___ is the white, fibrous portion.
cornea, sclera
Vascular layer (middle coat)
The posterior portion is the thin, heavily pigmented ___. The anterior portions include the circular ___, in which are incorporated the ciliary muscles (intrinsic eye muscles).
choroid, ciliary body
The ciliary muscles are attached to the rim of the lens by means of
____
suspensory ligaments.
To bend the light to focus it on the retina
Eye lenses
Attached to the anterior edge of the ciliary body is the colored iris, which has an opening called the ___.
pupil
The ___ of your eye is the black hole in the middle of your iris.
pupil
Your ___ is the colored part of your eye
iris
• Inner layer (inner coat) -
The retina is divided into two layers:
the outer pigmented retina and the inner sensory retina.
The ___ contains photoreceptor cells of two main types— rods and cones —as well as association neurons.
sensory retina
In the posterior retina is a small, yellow macula lutea with a pit called the ___.
fovea centralis
The ___ is normally the center of the visual field and contains many cones.
fovea
are specialized cells in the retina that convert light into signals the brain uses for vision.
Rods and cones
___ become more dominant farther away from the fovea.
Rods
Medial to the macula lutea is the white ___. Here, blood vessels, as well as the nerve fibers that exit as the optic nerve, pass out of the eyeball.
Optic disk
is a yellow oval spot in the center of the retina that provides sharp, detailed central vision. It’s also known as the fovea
macula lutea
These cells are concentrated near the fovea, the central area of the retina.
They are less sensitive to light than rods but have higher temporal resolution.
___ are responsible for color vision and can adapt quickly to changes in light. There are three types of it, each sensitive to different wavelengths of light: long (red), medium (green), and short (blue).
Cones
These cells are more numerous and located in the periphery of the eye. They are highly sensitive to light and are responsible for night vision and peripheral vision. __ detect shades of gray but do not discern color.
Rods
Filled with aqueous humor, a watery filtrate produced by the ciliary body.
Aqueous humor circulates from the posterior chamber behind the iris, through the pupil, and to the anterior chamber, where it is reabsorbed.
Anterior cavity
Filled with transparent, jelly-like vitreous body. This cavity is posterior to the lens.
Posterior cavity
The nerve bundle projecting from the posterior of the eyeball
Optic nerve
These may have been cut from your specimen during preparation
Extrinsic eye muscles (six)
The white portion of the vascular layer
Sclera
The clear, anterior portion of the vascular layer
Cornea
The pigmented region under the cornea
Iris
The iris’s hole (it may be oblong in your specimen rather than round as in the human)
Pupil
The thin mucous membrane over the anterior portion of the eye, extending to line the inner eyelid
Conjunctiva
The thick jelly-like substance of the posterior cavity
Vitreous body
A watery liquid in the anterior cavity
Aqueous humor
A plastic-like ball of translucent tissue (in fresh specimens it is very clear; hold it up and try to look through it)
Lens
A ring of ridges around the outside of the iris’s margin (the ridges are formed by the ciliary muscles within
Ciliary body
A thin film of gray matter loosely associated with the inside posterior wall of the eyeball (it may have fallen away, appearing as a crumpled mass still attached at the optic disk)
Retina
The pigmented region of the vascular layer in the posterior region of the eyeball’s wall, deep to the sclera and superficial to the retina.
Choroid -
In some mammals but not in humans, an ___ can be seen in the choroid.
iridescent tapetum lucidum
A fold of skin that closes over the eye to protect it
Eyelids
Transparent mucous membrane adhering to the anterior surface of the eye and lining of the eyelids
Conjuctiva
