Eye & Eye Movements (Part 2) Flashcards
What are the layers of the eyeball?
Fibrous Layer
Vascular Layer
Inner Layer
What is included in the fibrous layer of the eyeball?
Sclera (whites of the eye)
Cornea (clear part - look through it)
What is included in the vascular layer of the eyeball?
Choroid
Ciliary Body
Iris (color of eye)
What is included in the inner layer of the eyeball?
Retina
What is the retina connected to?
Optic N.
What is inside of the Optic N.?
Central Retinal V.
Central Retinal A.
T/F. The Optic N. is surrounded by the meninges.
True
This is what lines the innermost part of the eyelids.
Palpebral Conjunctiva
This is what lines the outermost part of the eyeball.
Bulbar (Ocular) Conjunctiva
The conjunctiva come together at what locations?
Superior Conjunctional Fornix
Inferior Conjunctional Fornix
The Levator Palpebrae Superioris M. inserts on the eyelid and pulls open the eyelid. What innervates this?
CN III (Oculomotor) – Superior branch
The Superior Tarsal M. inserts on the eyelid and keeps the eyelid open. What innervates this?
Sympathetics
This is caused by the inflammation of the conjunctiva and can be either bacterial (oozing, crusties in eye) or viral (red, painful).
Conjunctivitis
This is caused by the rupture of a blood vessel between the Sclera and Bulbar Conjunctiva. It’s due to an increase in intra-abdominal pressure (i.e., blowing nose, pooping, etc.)
Subconjunctival Hemorrhage
What is the difference between Complete Ptosis and Partial Ptosis?
Complete Ptosis is from a problem with CN III causing the Levator Palpebrae Superioris M. to not work.
Partial Ptosis is from a problem with sympathetic fibers causing the Tarsal muscle to not work. This presents in Horner’s.
This is caused by increased intracranial pressure. Pressure on the meninges and in the Subarachnoid Space can cause a bulging optic disc. Emergent and need to find the cause of the intracranial pressure ASAP.
Papilledema
Branches of the arteries supplying the eye originally come off of what?
Internal Carotid A.
This is what branches off the ICA and distally becomes Supratrochlear A. and Supraorbital A.
Ophthalmic A.
This artery branches off the Ophthalmic A. and goes straight into the Optic N.
Central Retinal A.
The Supraorbital A. (off of Ophthalmic A.) anastomoses with what?
Superficial Temporal A. (off of External Carotid A.)
The Supratrochlear A. (off of Ophthalmic A.) anastomoses with what?
Angular A. (terminal part of Facial A.)
The Anterior and Posterior Ethmoidal As. (off of Ophthalmic A.) anastomose with what?
Sphenopalatine As. (off of Maxillary A.)
The Middle Meningeal A. (off of Maxillary A.) anastomoses with what?
Lacrimal A. (off of Ophthalmic A.)
Why are the anastomoses near the eye important?
Because the Central Retinal A. does not anastomose with anything! Blood has to be able to reach it, because if it can’t then you will go blind.
***This is ONLY with a slow occlusion. If it’s a quick occlusion like a thrombus or clot then the anastomoses can’t compensate and the tissue will die.
This vein is near the nose and is part of the danger triangle on the face. It can cause infection by emptying into the Superior/Inferior Ophthalmic Vs. which empty back into the Cavernous Sinus.
Angular V.
This occlusion is due to the hardening of the Central Retinal A., and hypertension in the Central Retinal A. causing it to be compressed. Hemorrhages and dilated veins can occur. It has a “ketchup” appearance.
Central Retinal V. Occlusion
This occlusion is due to atherosclerosis or an embolism. The retina appears pale and white and there is a cherry red spot (macula). Veins and arteries are attenuated.
Central Retinal A. Occlusion
Describe the steps of tear production to drainage.
Lacrimal gland creates tears and they secrete. You blink, which makes the tears go medially toward the Lacrimal Canaliculi. On this are Puncta, which wick the tears into the Lacrimal Sac. The Sac drains into the Nasolacrimal Duct. The Duct will then drain into the Inferior Nasal Meatus (inside of Inferior Nasal Concha).
***Runny nose from crying!!!
Why does it help to blink a lot when you’re crying?
The Lacrimal part of the Orbicularis Oculi M. is inserted onto the Lacrimal Sac. When you blink, this muscle pulls and creates negative pressure on the Sac. This causes it to drain tears down instead of onto your cheeks.
Describe the path for the Facial N. parasympathetics.
Facial N. enters through Internal Auditory Meatus and is in the Petrous part of Temporal bone. Passes through the Geniculate Ganglion and exits via the Hiatus for Greater Petrosal N. Now it is the Greater Petrosal N. and it meets up with the Deep Petrosal N. (sympathetic). They pass over the Foramen Lacerum (not into it) and enter the Pterygoid Canal. Becomes the N. of the Pterygoid Canal, then exits and synapses in the Pterygopalatine Ganglion. Post-synaptic fibers jump on Trigeminal N. branches and go on to innervate the glands.
Put the steps of tear production in order:
A. Parasympathetic fibers synapse in Pterygopalatine Ganglion.
B. Greater Petrosal N. (CN VII) and Deep Petrosal N. (sympathetic) form N. of Pterygoid Canal.
C. Travel with Zygomatic branch (V2)
D. Travel with Lacrimal N. (V1)
E. Travel with Communicating Branch
F. Tears produced
1) B
2) A
3) C
4) E
5) D
6) F
***Remember, the Trigeminal N. (CN V) is just a highway for the parasympathetics!!!
This chamber of the eye is the space between the cornea and the iris/pupil.
Anterior Chamber
This chamber of the eye is the space between the iris/pupil and the lens and ciliary body.
Posterior Chamber
This chamber is behind the lens and ciliary body.
Vitreous Chamber
These secrete aqueous humor which fills the anterior and posterior chambers of the eye.
Ciliary Processes
This is the circumferential tissue inside the eye and is composed of the ciliary muscle and ciliary processes. It is important for parasympathetics and is innervated by CN III.
Ciliary Body
Put the following in order from first to last for the flow of aqueous humor:
Anterior Chamber
Ciliary Body
Scleral Venous Sinus (Schlemm’s Canal)
Posterior Chamber
1 – Ciliary Body
2 – Posterior Chamber
3 – Anterior Chamber
4 – Scleral Venous Sinus (Schlemm’s Canal)
Blockage of Schlemm’s Canal (Scleral Venous Sinus) can lead to increase intraocular pressure and _________. This compresses the Optic N. and can make you go blind.
Glaucoma
This is caused by the rupture of blood vessel that fill the anterior chamber of the eye. It can happen when you’re hit in the eye (i.e., sports, fighting, etc.)
Hyphema
What are the 3 things that occur with accommodation of the eye?
- Convergence of Lens
- Pupil Constriction
- Rounding of Lens
If the ciliary muscles are flexed, they bunch up similar to a bicep. This makes _______ _______ relax, which are the suspensory ligaments of the lens. If these are relaxed, then the lens can make a perfect sphere. When the lens is round then it can focus light and have _______ vision.
Zonular Fibers
Near
If the ciliary muscles are relaxed, then the Zonular Fibers are pulling on the lens. This makes the lens long and flat, which allows _______ vision.
Far
