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90 Cards in this Set
- Front
- Back
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What bones participate in forming the bony orbit? |
- frontal, lacrimal, zygomatic, sphenoid, maxillary, and temporal |
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What species do not have a closed orbit? What is the orbit closed by? |
- carnivores - orbital ligament |
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Where is the retrobulbar fat found? |
- occupies the potential space caudodorsally between the eye and temporalis muscle |
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What is the connective tissue sheath that surrounds the eyeball and the ocular adnexa arranged like a cone? |
- periorbita |
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What is the pulley-shaped cartilage called? |
- trochlea |
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What muscle does the trochela direct? What is the location? |
- directs the course of the dorsal oblique muscle - located dorsomedially |
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What is the palpebrae? What are the names of the two palpebrae? |
- palpebrae are the eyelid - superior and inferior palpebrae |
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What is the space enclosed by the superior and inferior palpebrae called? |
- palpebral fissure |
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What are the two commissures found in the eye called? |
- medial and lateral commissures - the "corners" of your eye |
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What two ligaments are found next to the two commissures? |
- medial and lateral palpebral ligaments |
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Where do dogs have eyelashes? Cats? Horse/Ox? |
dogs: upper only cats: none horse/ox: both upper and lower |
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What gland is found at the opening margin of the eyelid? Which eyelid is it better developed in? What type of modified gland is it? |
- Tarsal gland - better developed on the upper eyelid - modified sebaceous glands |
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What is the common name for the pilca semilunaris or nictitating membrane? |
- third eyelid |
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What is the third eyelid comprised of? |
- fold of palpebral conjunctiva and a T-shaped piece of cartilage |
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What type of tissue is found on the medial surface of the third eyelid? |
- lymphoid tissue |
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What are the glands associated with the third eyelid? |
- superficial gland - deep gland (harderian) |
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Where is the superficial gland of the third eyelid found? What is its function? |
- present at the base of the cartilage - contribute to the production of tear film |
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What species have the deep gland of the third eyelid? |
- ox and pig |
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What are the three muscles of the eyelid? What are they innervated by? |
- orbicularis oculi - retractor anguli oculi lateralis - levator anguli oculi medialis
ALL INNERVATED BY FACIAL NERVE |
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What is the action of orbicularis oculi? |
- closes palpebral fissure |
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What is the action of retractor anguli oculi lateralis? |
- covers lateral palpebral ligament |
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What is the action of levator anguli oculi medialis? |
- raises eyelid |
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What is the flow of tears in order? |
- lacrimal gland (dorsolateral in position), lacrimal ducts, surface of the eye, lacrimal lake, debris is removed in lacrimal caruncle, lacrimal puncta (superior and inferior), lacrimal canals, lacrimal sac, nosolacrimal duct, nasal vestibule |
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What are the three tear film layers? |
- outer: lipid layer, produced by the tarsal gland - middle: aqueous layer, produced by the lacrimal gland - inner: mucinous layer, produced by goblet cells of the conjunctiva |
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What species have an accessory lacrimal glandular tissue located in the superficial gland and deep glands of the third eyelid? |
- Ox and pig |
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What are the four parts of the conjunctiva? |
- palpebral conjunctiva - bulbar conjunctiva - conjunctival fornix - conjunctival sac |
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What does the palpebral conjunctiva line? |
- eyelids |
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What does the bulbar conjunctiva line? |
- eye ball |
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What are the extrinsic ocular muscles? |
- levator palpebrae superioris - dorsal rectus - ventral rectus - lateral rectus - medial rectus - ventral oblique - dorsal oblique - retractor bulbi |
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Where do all the extrinsic ocular muscles originate from? Except for which? |
- all arise from the optic foramen - except ventral oblique, originates form a depression in the ventromedial wall of the orbit |
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All the extrinsic ocular muscles attach where? Except for which? |
- all insert on the sclera - except levator pulpebrae superioris, inserts on the upper eyelid to elevate it |
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What is the action of levator palpebrae superioris? |
- elevate superior palpebrum |
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What is the action of dorsal and ventral rectus m? |
- rotate eyeball around a horizontal axis |
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What is the action of the lateral and medial rectus m? |
- rotate eyeball around around a vertical axis |
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What is the function of the dorsal oblique m? |
- pulls dorsal part of eyeball medially |
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What is the action of the ventral oblique m? |
- pulls dorsal part of eyeball laterally |
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What innervates the dorsal oblique m? |
- trochelar nerve |
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What innervates the lateral rectus and retractor bulbi m? |
- abducent nerve |
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What innervates all the other muscles? |
- oculomotor nerve |
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What cranial nerves are associated with the eye? |
- optic - oculomotor - trochlear - trigmeinal - abducens - sooooo 2,3,4,5,6! |
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What foramen does the optic nerve come out of? |
- optic canal |
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What nerves come out of the orbital fissure? |
- oculomotor - trochlear - opthalmic n of trigeminal - abducens |
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Where does the maxillary nerve come out? |
- round foramen |
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What is the function of optic nerve? |
- vision |
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What muscles are innervated by the oculomotor nerve under somatic motor control? |
- dorsal rectus - ventral rectus - medial rectus - ventral oblique - levator palpebrae superioris |
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What is innervated by the oculomotor nerve under visceral motor control? |
- ciliary ganglion - parasympathetic innervation to sphincter papillae m and ciliary m |
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What muscles does the trochelar n innervate? |
- dorsal oblique |
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What does the ophthalmic branch of trigeminal innervate? |
- longciliary nerves of the eyeball |
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What is a branch of ophthalmic? What does it innervate? |
- infratrochelar n - medial aspect of superior and inferior palpebrae |
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What branch of the maxillary nerve of the trigeminal innervated the lacrimal gland and the lateral aspect of the superior and inferior palpebrae? |
- zygomatic nerve |
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What two nerves innervate the superior and inferior palepbrae? |
- medial: infratrochelar n of ophthalmic of trigeminal - lateral: zygomatic n of the maxillary n of the trigeminal |
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What does the abducens innervate? |
- lateral rectus m - retractor bulbi m |
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The corneal and palpebral reflex involves what afferent nerve? Efferent? |
afferent: efferent: |
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Describe how light passes through the eye. |
- light passes through the cornea and lens, is focused on the retina, transformed by rods and cones and transmitted by optic nerve to brain for processing |
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What is the spot called where the optic disc attaches? |
- optic disc (blind spot) - slightly ventral to the posterior pole of the eyball |
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What is the area of maximum optical resolution called? What is its location? |
- macula - located dorsolateral to the optic disc |
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The anterior compartment is between what? What does it contain? |
- between cornea and lens - contains aqueous humor |
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What are the two chambers of the anterior compartment? |
- anterior and posterior chambers |
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What are the boundaries of the anterior chamber? |
- bounded by cornea and iris |
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What are the boundaries of the posterior chamber? What does it communicate with? |
- bounded by iris and lens - communicates with anterior chamber through pupil |
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What is the posterior compartment between? What does it contain? |
- between lens and retina - contains vitreous body |
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What are the three layers of the eyeball? |
1. Fibrous tunic 2. Vascular tunic 3. Nervous tunic |
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What are the two parts of the fibrous tunic? |
- cornea - sclera |
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What are the three parts of the vascular tunic? |
- choriod - cilary body - iris |
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What is the nervous tunic called in everyday terms? |
- retina |
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Which part of the fibrous tunic is transparent and avascular? |
- cornea |
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Which part of the fibrous tunic is a tough fibrous layer? |
- sclera |
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What is the corneoscleral junction called? |
- limbus |
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Is the choriod well vascularized? What structure does it supply with nutrients? |
- well vascularized - supplies retina with nutrients |
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What is a part of the chorid that reduces illumination and is a light reflective surface? |
- tapetum lucidum |
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What is the anterior continuation of the choriod called? |
- cilary body and processes |
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What anchors the lens in place? |
- cilary processes with lens zonules (suspensory ligaments of the lens) anchor lens in place |
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Are cilary muscles smooth ? |
yes |
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What happens when the cilary muscles contract? |
- contracts under PS control (CNIII) to stretch cilary body releasing tension on the suspensory ligaments of the lens - lens becomes thicker and more convex - allows for accommodation, focusing on nearby objects |
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What lies between posterior and anterior chambers? |
- iris |
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What muscle forms concentric rings around the pupil? What is the innervation? Action? |
- sphincter pupillae muscle - PS CN III - constricts pupil |
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What muscle is has radially oriented fibers along the caudal border of the iris? What is the innervation? Action? |
- dilator pupillae muscle - innervation by sympathetic nervous system - dilates pupil |
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What is the transparent biconvex disk located directly behind the pupil and focuses light rays on retina? |
- lens |
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What is the circulation of the aqueous humor? |
- produced by cilary processes - posterior chamber - pupil - anterior chamber - irdocorneal angle - venous scleral sinus
provides nutrients and oxygen for lens and cornea |
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What are the two part so the nervous tunica? |
- visual retina - non-visual retina |
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What is one part the visual retina? What does it cover and contain? |
- pars optica retinae - covers fundus of eye - contains rods and cones |
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What are the two parts of the non-visual retina? |
- pars cilaris retinae - pars iridica retinae |
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What does the pars cilaris retainae cover? Pars iridica retinae? |
- pars cilaris retainae: covers cilary body and processes - pars iridica retainae: covers posterior iris |
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What is the junction of visual and non-visual retinae called? |
- ora serrata |
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What species have corpus nigrum (iridic granules) |
- ungulates |
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What are the nerves exiting through the foramen orbitorotundum? |
- oculomotor, trochelar, and abducens: motor to extrinsic eye muscles - ophthalmic of trigeminal: sensory from the medial canthus area, lacrimal gland, eyeball - maxillary n of trigeminal: sensory from the lateral canthus area, skin of inferior palpebra and ventral to this region, and skin between the eye and ear |
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What nerve crosses over the zygomatic arch to innervate the muscles of the palpebrae? |
- auriculopalpebral n of facial n |
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Why is the peterson's eye block used? |
- enucleation of the bovine eye |
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Describe the Peterson eye block. |
- anesthetizes nerves exiting the foramen orbitorotumdum: site of anesthetic block is just rostral to foramen orbitorotundum - insert need in depression just caudal to angle formed by frontal and temporal process of zygomatic bone, prerygoid crest is located lateral to the foramen orbitorotundum - block the auriculopalpebral n of facial n crosses over the zygomatic arch |
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What is the blood supply to the eye? |
- primarily from external ophthalmic off of maxillary n of external carotid artery |
