Exam 7 Eye Special Senses 72X Flashcards
Name the accessory structures of the eye?
Eyelids Eyelashes Eyebrows Lacrimal Apparatus Extrinsic Eye Muscles
What is the term used for the upper and Lower eyelids?
Palpebrae
What muscle is responsible of moving the upper eyelid?
Levator Palpebrae Superioris
What is the space between the upper and lower eyelids termed?
Palpebral Fissure
What term is used for the angles of the palpebral fissures?
Medial Commissure
Lateral Commissure
What is contained in the medial commissure?
Lacrimal Caruncle
- Sebaceous (oil) Glands
- Sudoriferous (Sweat) Glands
Name the structures of the eyelid from superficial to deep?
-Epidermis
-Dermis
-Subcutaneous
Tissue
-Fibers of Orbicularis Oculi Muscle
-Tarsal Plate
-Tarsal Glands
-Conjunctiva
What is the name of the structure of the eye that is a thick fold of connective tissue that gives form and support to the eyelid?
Tarsal Plate
Tarsal Glands (Meibomian Glands) Characteristics?
- Modified Sebaceous Glands in ea Tarsal Plate.
- Secrete fluid that prevent eyelids from adhering to ea other
What is the thin, protective mucous membrane composed of stratified columnar epithelium w/many goblet cells?
Conjunctiva
What lines the inner aspect of the eyelids?
Palpebral Conjunctiva
What conjunctiva is on the anterior surface of the eyeball? What does it cover?
Bulbar conjunctiva (AKA Ocular Conjunctiva) -Sclera, but not the cornea
What is the group of structures that produces and drains lacrimal fluid or tears? What is Lacrimal Fluid composed of?
Lacrimal Apparatus
-Watery Solution: Salts, Mucus, and lysozyme (bactericidal enzyme)
Describe the process of tear (Lacrimal Fluid) production to drainage?
-Lacrimal Glands secrete Lacrimal Fluid
-Drains through excretory lacrimal duct onto conjunctiva of upper lid
-Tears pass medially over eyeball
-Enter Lacrimal Puncta (two)
-Pass into Lacrimal Canals (Two) (Superior and Inferior)
-Enter Lacrimal Sac
-Enter Nasolacrimal Duct
Enter Nasal Cavity
Name the six Extrinsic eye Muscles?
Superior Rectus Inferior Rectus Lateral Rectus Medial Rectus Superior Oblique Inferior Oblique
What is significant about the neurons and how they are able to permit smooth, precise, rapid movements of the eyes?
Serve only two or three muscle fibers (commonly 8-12)
Which muscles preserve the rotational stability of the eyeball?
Oblique Muscles
- Superior Oblique
- Inferior Oblique
How many Cardinal directions of eye movement are there and name the directions?
8
- Superior (up)
- Inferior (down)
- Nasal (in)
- Temporal (out)
- Up and In
- Up and Out
- Down and In
- Down and Out
What term is used to refer to the name of the six Cardinal Directions of eye movement associated w/a single extrinsic muscle? Name the Muscle and Direction?
Cardinal Directions Of Gaze
- Superior Rectus: Up and In
- Medial Rectus: In
- Inferior Rectus: Down and In
- Superior Oblique: Down and Out
- Lateral Rectus: Out
- Inferior Oblique: Up and Out
What are the muscles involved and directions of movement for the two Cardinal Directions that involve two muscles working in concert?
Superior Rectus and Inferior Oblique: UP
Inferior Rectus and Superior Oblique: Down
Name the Cranial Nerve Involved in the Cardinal Directions of Gaze for all Inward movements and the Up and Out movement?
CN-III (Oculomotor Nerve)
- Inferior Oblique: Up and Out
- Superior Rectus: Up and In
- Medial Rectus: In
- Inferior Rectus: Down and IN
What cranial nerve and muscle are involved in the Down and Out Cardinal Directions of Gaze Movement of the eye?
CN-IV (Trochlear Nerve)
-Superior Oblique: Down and Out
Name the Muscle and Cranial Nerve for the Cardinal Direction of Gaze eye movement of In?
Medial Rectus Oculomotor Nerve (CN-III)
Name the Muscle and Cranial Nerve for the Cardinal Direction of Gaze eye movement of Down and Out?
Superior Oblique Trochlear Nerve (CN-IV)
Name the Muscle and Cranial Nerve for the Cardinal Direction of Gaze eye movement of Up and In?
Superior Rectus Oculomotor Nerve (CN-III)
Name the Muscle and Cranial Nerve for the Cardinal Direction of Gaze eye movement of Out?
Lateral Rectus Abducens Nerve (CN-VI)
Name the Muscle and Cranial Nerve for the Cardinal Direction of Gaze eye movement of Up and Out?
Inferior Oblique Oculomotor Nerve (CN-III)
Name the Muscle and Cranial Nerve for the Cardinal Direction of Gaze eye movement of Down and In?
Inferior Rectus Oculomotor Nerve (CN-III)
Name the Muscle and Cranial Nerve for the Cardinal Direction of eye movement for Up?
Superior Rectus and Inferior Oblique Oculomotor Nerve (CN-III)
Name the Muscle and Cranial Nerve for the Cardinal Direction of eye movement for Down?
Inferior Rectus and Superior Oblique Oculomotor Nerve (CN-III) and Trochlear Nerve (CN-IV)
What does the Helpful pneumonic “LR6(SO4)3 refer to? Eye, Nerve, and muscle innervation?
LR6: Lateral Rectus: CN-IV (Abducens Nerve)
SO4: Superior Oblique CN-IV (Trochlear Nerve)
3: All other Muscles CN-III (Oculomotor Nerve)
By having a Patient fully abduct their eye first and look Down and Out what Muscle and Nerve is used to depress the eye rather than the Superior Oblique and CN-IV?
Inferior Rectus CN-III
By having a Patient fully abduct their eye first and look Down and In what Muscle and Nerve is used to depress the eye rather than the Inferior Rectus and CN-III?
Superior Oblique CN-IV
By having a Patient fully abduct their eye first and look Up and Out what Muscle and Nerve is used to Elevate the eye rather than the Inferior Oblique and CN-III?
Superior Rectus CN-III
By having a Patient fully abduct their eye first and look Up and In what Muscle and Nerve is used to elevate the eye rather than the Inferior Oblique and CN-III?
Superior Rectus CN-III
What is the term that refers to an imbalance in the extrinsic eye muscles resulting in misalignment of one eye so that its line of vision is not parallel with that of the other eye (Cross-eyes), to compensate, normal and deviant eyes may alternate focusing on objects?
Strabismus
In some cases of strabismus the dominant/controllable eye is used by the brain for input and the deviant eye is disregarded in which it becomes functionally blind, what are some treatments for less severe cases?
Exercises to strength weak muscles or temporarily placing a patch on stronger eye forcing the weak eye to work. “Lazy eye” is the layman’s term
What is a Nystagmus?
Rapid involuntary movement of the eyeballs. May be inherited, idiopathic, or caused by disease Of CNS. It is a sign not a disease
What form of Nystagmus occurs much less frequently than horizontal nystagmus, which horizontal is used by police for sobriety checks?
Vertical Nystagmus
What type of Nystagmus is a complex of eye movements that occurs during and immediately after rotational motion?
Vestibular Nystagmus
Name the layers of the eye?
Fibrous Tunic
Vascular Tunic
Retina
What does the Fibrous Tunic Consist of?
Consist of: Cornea and Sclera
- Superficial coat of Eyeball
- Avascular
Describe the Cornea and Function:
Transparent coat covering Iris Curved to focus light 3 Layers: -Outer- Nonkeratinized Stratified Squamous Epithelium -Middle- Collagen Fibers and Fibroblasts -Inner- Simple Squamous Epithelium
What is the “White” of the eye?
Sclera
The Sclera is composed of what type of tissue and covers what portion of the eye?
- Dense connective tissue, collagen and fibroblasts
- Entire eyeball except at Cornea
What does the Sclera do for the eye Functionally?
Gives Shape
Makes more rigid
Protects inner parts of the eye
What are the three parts to the middle layer of the eye, the Vascular Tunic?
Choroid
Ciliary Body
Iris
What portion of the Vascular Tunic is highly vascular, lines most of the internal surface of the sclera, and provides nutrients to the posterior surface of the sclera?
Choroid
What does the Ciliary Body consist of?
Ciliary Processes
Ciliary Muscle
What portion of the Ciliary Body forms protrusions or folds on the internal surface of the ciliary body and contains blood capillaries that secrete aqueous humor?
Ciliary Processes
Describe the Ciliary Muscle?
- Circular band of smooth muscle, alters shape of lens
- Contract: reduces tension on suspensory ligaments that hold lens allowing a more spherical shape (close vision)
What is the colored portion of the eye and is attached at its outer margins to the ciliary processes?
Iris
How does the Iris regulate light entering the eye?
Autonomic Reflexes
- Parasympathetic Neurons: Stimulate sphincter Pupillae (Circular muscles) to contract (Constriction)
- Sympathetic Neurons: Stimulate Dilator Pupillae (Radial Muscles) to contract (Dilation)
What lines the posterior 3/4th of the eyeball and is the beginning of the visual pathway?
Retina
What is the significance of the retina and what can be seen with an ophthalmoscope?
Only place on the body where blood vessels can be viewed directly and examined for pathological changes
What is the Optic Disc?
Site where Optic Nerve Exits eyeball
Central Retinal Artery and Central Retinal Vein: adjacent to optic disc
What layer of the retina is a sheet of melanin-coated epithelial cells and absorbs stray light, preventing reflection and scattering?
Pigmented Layer
What layer of the retina is an outgrowth of the brain?
Neural Layer
The Neural Layer has three distinct layers of retinal neurons, what are they?
Photoreceptor Layer
Bipolar Layer
Ganglion Layer
What are the two zones that lie between each layer of retinal neurons of the neural layer?
Outer Synaptic Layer
Inner Synaptic Layer
Name the sequence of layers that light passes through the retina?
Optic Nerve Ganglion Cell Layer Inner Synaptic Layer (Zone) Bipolar Cell Layer (Horizontal Cell, Bipolar Cell, Amacrine Cell) Outer Synaptic Layer (Zone) Photoreceptor Layer (Rods and Cones) Pigmented Layer
What is the Sequence of layers in which visual data processing through the retina occurs?
Pigmented Layer Photoreceptor Layer (Rods and Cones) Outer Synaptic Layer (Zone) Bipolar Cell Layer (Horizontal Cell, Bipolar Cell, Amacrin Cell) Inner Synaptic Layer (Zone) Ganglion Cell Layer Optic Nerve
What are the two types of photoreceptors that transduce light rays into receptor potentials, found in the Neural layer of the retina and in the Photoreceptor layer of the neural layer?
Rods
Cones
Rods have what type of threshold and see what shades and/or colors?
Low Light threshold
Shades of gray
Cones have what type of threshold and see what shades and/or colors?
High light threshold Color vision (R 60%, G 30%, B 10%)
What is the exact center of the visual axis of the eye of the posterior portion of the retina?
Macula Lutea
What is the small depression in the center of the macula lutea?
Central Fovea (Fovea Centralis)
The Central Fovea only contains what photoreceptors?
Cones
What Cells of the Neural Layer do not cover the cones in the central fovea and for what reason is this?
Bipolar and Ganglion Cells
-These cells scatter light to some extent
What is so significant about the Fovea Centralis?
Area of highest visual acuity (visual resolution)
What area of the eye contains no rods or cones and what is this area considered?
Optic Disc Blind Spot (image strikes the optic disc cannot be seen)
What is the degenerative disorder of the retina and pigmented layer which may being at age 50 and abnormalities occur in region of macula lutea, advanced condition patient retains peripheral vision but loses ability to see straight ahead? What is the other name for this disease?
Age-Related Macular Disease
AKA Macular Degeneration
What are the two forms of Age-Related Macular Disease (Macular Degeneration) and what are their characteristics?
- Dry: Central vision gradually diminishes as pigmented layer atrophies and degenerates. No treatment
- Wet: New blood vessels form in choroid and leak plasma and blood under retina. Treatment lase surgery
What structure of the eye lies behind the pupil and iris and consists of proteins called crystallines, arranged like layers of an onion and enclosed in a capsule?
Lens
What are some key characteristics of the Lens?
Transparent
Lacks Blood Vessels
Variably Refractive medium of the eye
The loss of transparency of the lens due to changes of the structure of the lens proteins, due to aging, UV light, medication (long-term steroid), disease (diabetes), chemical (glutaraldehyde, osmimum tetroxide), higher risk smoking, etc… is called what?
Cataracts
What are the two cavities of the lens?
Anterior Cavity
Vitreous Chamber
What does the Anterior Cavity consist of and what fills these?
Anterior Chamber (between cornea and iris) Posterior Chamber (Behind iris and in front of lens) -Aqueous Humor fills the chambers
What is a major contributor of intraocular pressure and is manufactured by filtration of blood by the capillaries of the ciliary processes?
Aqueous Humor
Where does the Aqueous Humor flow?
- Between Iris and Lens through Pupil into Anterior Chamber
- Drains into Scleral Venous Sinus (Canal of Schlemm)
- Returns to blood
The Scleral Venous Sinus (Canal of Schlemm) lies where within the eye?
Junction of Sclera and Cornea
How often is the Aqueous Humor replaced?
Approx. 90 minutes
What form of Glaucoma occurs from pressure from posterior chamber pushing iris forward closing ocular angle and preventing drainage of aqueous humor?
Primary Closed Angle Glaucoma
What causes Primary Open Angle Glaucoma (Ocular Angle remains open)?
Abnormalities in Trabecular Meshwork associated w/ Schlemm’s Canal (Scleral Venous Sinus) impede outflow of Aqueous humor
Glaucoma is treated with what?
Cholinergic agonists (Cholinomimetcs), constrict pupil, contract ciliary muscles, and decrease intraocular pressure.
(Closed Angle: pulls iris away from canal opens it)
(Open Angle: stretches trabecular meshwork, opens)
The larger of the two cavities of the lens is called what and what does it contain?
Vitreous Chamber
Contains: Vitreous Body
What is the Vitreous Body in which is found within the Vitreous Chamber?
- Jellylike (Water, Hyaluronic Acid, Collagen) 4mL
- Contributes to intraocular pressure
- Holds retina flush against choroid
- Formed during embryonic development and not replaced
- Contains phagocytic cells, remove debris, unobstructed vision
The Hyaloid Canal running through the Vitreous Body is remnant of what?
Hyaloid Artery
Retinal tears and retinal detachment are most often seen where in the eye?
Behind Ora Serrata
Optic Disc
What is the serrated junction between the retina and ciliary body called?
Ora Serrata
What does the Ora Serrata junction mark?
Transition from Simple non-photosensitive area of retina to complex, multi-layered photosensitive region
What attaches anteriorly just behind the ora serrata?
Vitreous Body
What term is used for inflammation of the eyelid?
Blepharitis
Defined: Inflammation of the conjunctiva due to bacteria (contagious) or irritants (not contagious)?
Conjunctivitis (Pinkeye)
Defined: Scratch on the surface of the cornea?
Corneal Abrasion
Defined: Procedure in which a donor cornea replaces a removed defective cornea?
Corneal Transplant
Defined: Degenerative Disease of retina due to diabetes mellitus, in which blood vessels in the retina are damaged or new ones grow and interfere w/vision?
Diabetic Retinopathy
Defined: Turning outward of the eyes?
Exotropia
Defined: Inflammation of infection of the cornea?
Keratitis
Defined: Constriction of the pupil?
Miosis
Defined: Dilation of the pupil?
Mydriasis
Defined: Abnormal visual intolerance to light?
Photophobia
Defined: Falling or drooping of the eyelid (or slippage of any organ below its normal position)?
Ptosis
Defined: Tumor arising from immature retinal cells; accounts for 2% of childhood cancers?
Retinoblastoma
Defined: Area of reduced or lost vision in the visual field?
Scotoma
Defined: Instrument for measuring intraocular Pressure?
Tonometer
Defined: Serious form of conjunctivitis, and greatest single cause of blindness in the world, caused by bacterium of Chlamydia Trachomoatis; Produces an excessive growth of sub-conjunctival tissue and invasion of blood vessels into the cornea, progressing until the entire cornea is opaque?
Trachoma
