Chapter 13: Anatomy of the Eye Flashcards
Ophthalmology
study of the eye
Define eyeball
organ of sight
What 3 layers is the eyeball composed of?
sclera, choroid, and the retina
What is the Sclera and its function?
Outer layer; provides a tougth protective coating for the inner structures of the eye
White of the eye
What is the Cornea’s relationship to the Sclera?
Anterior porion of the sclera
What is the Cornea and its function?
Clear, a transparent area that allows light to enter the interior of the eyeball
Refracts (bends) light rays
What is the Choroid?
2nd or middle layer of the eyeball- opaque
What is the function of the Choroid?
Provides blood supply for the eye
What does the Choroid contain?
Iris, pupil, ciliary body
What is the Iris?
colored portion of the eye and contains smooth muscle
What is the function of the Iris?
Contracts or relaxes to change the size of the pupil- controlling how much light enters the interior of the eyeball
What is the pupil/function?
opening in the center of the iris that allows light rays to enter the eyeball
What is the Ciliary body’s function?
Attached to the lens( not part of the Choroid layer; Pulling on the edge of the lens- muscles change the shape of the lens so it can focus incoming light into the retina
What is the suspensory ligament and its function?
from the ciliary body and is attached to the lens; (pulls on the lens)
What is the retina
Third and innermost layer of the eyeball
What does the Retina contain?
Sensory receptor cells (rods and cones), Macula Lutea (Fovea Centralis), Optic disk, Aqueous Humor and Vitreous Humor
What are Rods/ their function?
active in dim light and help us to see in gray tones
What are Cones/ their function?
active only in bright light and are responsible for color vision
What is the Macula Lutea (function)?
when looking at an object, this where the image falls
Yellow spot
What is the Fovea Centralis (including function)?
center of the Macula Lutea; a depression; central pit
High concentration of sensory receptor cells, the point of clearest vision
What is the Optic disk (including function)?
the point where retinal blood vessels enter and exit the eyeball and where the optic nerve leaves the eyeball
No sensory receptors- a blind spot in each eye’s field of vision
What is the Aqueous humor?
a watery fluid between the cornea and the lens
What is the Vitreous Humor?
a semisolid gel between the lens and retina
How many muscles connect the eyeball to the skull?
6
What are the 2 functions of the muscles of the eye?
Allow change in the direction of each eye’s sightline
Provide support for the eyeball in the eye socket
What is Strabismus?
crossed eyes
What treatments does Strabismus need?
eye excercises or surgery
What is Esotropia?
right eye turns inwards
What is Exotropia?
right eye turns outward
How many rectus muscles are there?
4
What do the rectus muscles do?
Pull the eye up, down, left or right in a straight line
How many oblique muscles are there?
2
What are the function of the oblique muscles?
On an angle and produce diagonal eye movement
What is the function of the eyelids?
Provides protection from foreign particles, injury from the sun and intense light and trauma
What does the eyelids contain?
eyelashes and sebaceous glands
What are the eyelashes?
(cilia) protect the eye from foreign particles
What are the sebaceous glands?
located in the eyelids that secrete lubricating oil onto the eyeball
What is the Conjuctiva?
Mucous membrane lining continuous covering on the underside of each eyelid and across the anterior surface of each eyeball
What is the function of the conjuctiva?
Protection for the eye by sealing off the eyeball in the socket
What does the Lacrimal Apparatus contain?
Lacrimal Gland and Lacrimal ducts
What is the Lacrimal Gland?
located under the outer upper corner of each eyelid
What odes the lacrimal gland do?
produces tears
What is the purpose of tears?
Serve the important function of washing and lubricating the anterior surface of the eyeball
What are the lacrimal ducts?
located in the inner corner of the eye socket
What is the function of lacrimal ducts?
Collects the tears and drain them into the nasolacrimal duct
Drains the tears into nasal cavity
What is the steps in which how we see?
- Light rays pass through the cornea, pupil, aqueous humor, lens, and vitreous humor
- Strike the retina and stimulate the rods and cones
- An upside-down image is produced by the retina and is sent along nerve impulses to the optic nerves
4.The optic nerve transmits impulses to the brain, where the upside-down image is translated into the right-side-up image
What are the 4 mechanisms that require proper functioning for vision?
a. Coordination of the external eye muscles so that both eyes move together
b.The correct amount of light admitted by the pupil
c.The correct focus of light on the retina by the lens
d.The optic nerve transmits sensory images to the brain
What are some names for the ciliary body?
Suspensiory ligament; zonular fibers; ciliary muscles; zonules; zonules of zin
What is the Canal of Schlem?
responsible for draining aqueuous humor from the anterior chamber
What are the nerves that supply the eye?
II. Optic: carries impulses for sense of sight
III. Oculomotor: motor impulses for eye movement and pupil ( superior rectus, inferior rectus, medial rectus and inferior oblique)
IV. Trochlear: Controls superior oblique muscle of eye on each side
V. Trigeminal: Nerve branches into eyes
VI. Abducens: controls eyeball muscles to move side to side (lateral rectus)
What type of pattern does the Superior Oblique muscle do?
A frame pattern
What type of pattern does the inferior oblique pattern do?
inverted A frame pattern
What is an Accommodation?
the ability of the lens to focus an image on the retina
What is another name for the optic disk?
optic nerve head
What is part of the anterior chamber?
cornea, iris, conjunctiva, lens (kind of)
