Special Senses: Ocular Flashcards by Adams Bruce Al-os

Lines the linear aspect of the eyelids

Palpebral conjunctiva

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Thin, transparent vascular tissue that extends from the limbus to the mucocutaneous junction of the eyelid.

Conjunctiva

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Covers the sclera

Bulbar conjunctiva

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Vascular supply of the conjunctiva

Anterior ciliary artery

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Conjunctiva is innervated by the 1st division of

CN V (Ophthalmic division)

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Fine, thin, elastic layer which covers the sclera. Underneath the conjunctiva. Contains numerous blood vessels which provides nourishment for the sclera.

Episclera

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Thick outer coat of the eye. Normally white and opaque. Avascular & fibrous (collagen). Continuous with the cornea anteriorly and with the dural sheath at the optic nerve posteriorly. _____ mm thick where the EOMs insert and about 1mm thick.

Sclera. 0.3.

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Transparent front window of the eye. Refracts light.

Cornea

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Layers of Cornea: nonkeratinized stratified squamous epithelium. Regenerative ability.

Corneal epithelium

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Layers of Cornea: collagen fibers

Bowman’s layer

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Layers of Cornea: thick layer (90%) of regularly arranged collagen fibers (type1), keratinocytes.

Corneal stroma

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Layers of Cornea: thin, strong layer.

Dual’s layer

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Layers of Cornea: thin acellular layer that serves as the modified basement membrane of the endothelium, collagen type IV.

Descemet’s membrane

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Layers of Cornea: monolayer of cuboidal cells, not able to regenerate, responsible for the corne’s deturgescence.

Endothelium

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The junction between sclera and cornea. May develop whitening as part of old age _______.

Limbus. Arcus senilis.

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The space between the cornea and iris. Contains a watery fluid called __________. Normally acellular. Cells seen in inflammatory and infectious decision.

Anterior chamber. Aqueous humor.

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Angle formed by the inner cornea and iris roots. Comprised several structure that make up the eye’s drainage system, _________ and ________.

Anterior chamber angle. Trabecular meshwork & Schlemm’s canal.

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Middle avascular layer of the eye. Composed of

Uveal tract. Ciliary body, Iris & Choroid.

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Contributes to the blood supply of the retina

Choroid

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Colored part of the eye that controls the amount of light that enters the eye.

Iris

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Hole at the center of the iris that, size is controlled by the iris muscle.

Pupil

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Accounts for the variety of colors seen. Dependent on the amount of pigment in the iris. Composed of BV,CT,Melanocyte & pigment cells.

Pigmented posterior surface

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Contains both dilator and sphincter muscles

Iris stroma

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Contraction of the sphincter muscle leads to

Pupil constriction

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Contraction of dilator muscle leads to

Pupil dilation

Blood supply of the iris

Major circle of the iris

Sensory innervation of the iris

Ciliary nerves

Circular opening at the center of the iris. Adjusts the amount of loght entering the eye.

Pupil

Parasympathetic activity of CN III will lead to

Pupillary constriction

Sympathetic activity of the pupil leads to

Dilation

Structure of the eye that produces aqueous humor

Ciliary body

Contraction of the ciliary body changes the tension of the ________ suspending the lens.

Zonular fibers

Change in tension leads to increased thickness of the lens which allows eye to focus at ______ objects ( _______ )

Near. Accomodation.

Vascular, pigmented layer between the sclera (externally) and retina (internally). Provides blood supply to the outer retinal layers.

Choroid

Biconvex structure. Refracts and focuses light on the retina. Suspended in place by zonule fibers. Anteroposterior _______ & Equatorial diameter _______.

Crystalline lens. 4-5mm. 9-10mm.

Narrow space behind the iris and in front of the zonule fibers. Space anterior to the crystalline lens. Filled with aqueous humor. Normally acellular.

Posterior chamber

Large space behind the lens. Extends up to the retina. Approximately ____ cc in volume. Filled with a transparent gel like material called ________.

Vitreous cavity. 4.5. Vitreous humor.

Thin, semitransparent, multilayer sheet of neural tissue lining the vitreous cavity.

Retina

Blood supply of Retina: branch of the ophthalmic artery. Supplies inner 1/3 of the retina.

Central Retinal Artery

Blood supply of Retina: supplied by the ophthalmic artery. Supplies outer 2/3 of the retina.

Choroid artery

Area of the retina responsible for fine & central vision.

Macula

Oval depression in the center of the macula. Approximately ___ disc diameters away from the optic disc.

Fovea. 2.

Not really a peripheral nerve, it is actually a direct extension of the CNS. 1.2 m axons. ___ mm long. Synapses at the lateral geniculate nucleus.

Optic nerve. 50.

Blood supply of the Optic nerve

Circle of zinn-haller

Optic nerve segment: 1mm long. 1.5 mmHg. Optic disc (visible by fundoscopy)

Intra ocular (optic nerve head)

Optic nerve segment: 25mm in length, 3 to 4.5 mm in diameter. Lined by dura, arachnoid and pia mater. Fuses at the apex of the orbit with periosteum and annulus of zinn.

Intra orbital

Optic nerve segment: 9mm in length. Firmly anchored to the bone (optic canal)

Intra canalicular

Optic nerve segment: 10mm long (3-16mm) just before it becomes the optic chiasm.

Intra cranial

Parietal and temporal lobes

Optic radiation

Occipital lobe

Visual cortex

X shaped structure wherein the medial fibers of both optic nerves decussate or cross to the other side. Suspended above the sella turcica.

Optic chiasm

Paired structures posterior to the optic chiasm. Composed of lateral fibers from the ipsilateral optic nerve and medial fibers from the contralateral optic nerve.

Optic tract

Sensory relay nucleus. Located in the thalamus.

Lateral geniculate body

Paired structure that carry visual information from the LGB to the visual cortex. Pass thru the parietal or temporal lobes.

Optic radiation

Inferior fibers that pass through the temporal lobe looping around the inferior horn of the lateral ventricle.

Meyer's loop

Striate cortex or VI. Occipital lobe. Responsible for image processing.

Primary visual cortex (BA 17)

Bony cavity which contains the eye. Pear shaped with the optic nerve representing its stem. Medial walls are parallel to each other, separated by the ethmoidal and sphenoidal sinuses.

Orbit

Fluid volume of orbit

30cc

Contains the lacrimal gland fossa

Orbital plate of the frontal bone

Contains the optic canal

Lesser wing of the sphenoid

Depression located at __mm from orbital margin. Serves as the attach,ent of the cartilaginous pulley from the superior oblique muscle.

Trochlear fovea

Contains the nasolacrimal canal and lacrimal sac.

Medial orbital wall

Paper thin medial wall is known as

Lamina papyracea

Lateral wall of the orbit formed by

Zygomatic bone & Greater wing of sphenoid

Thickest and strongest wall

Lateral wall of the orbit

Site of attachment for check ligament of lateral rectus muscle, suspensory ligament of eyeball, lateral palpebral ligament and aponeurosis of the levator ligament.

Lateral orbital tubercle

Roof of the maxillary sinus. Contains the infraorbital groove. Made up of 3 bones. Maxillary, palatine and orbital plate of zygomatic bone.

Floor of the orbit

Arises from the orbital floor. Only Extraocular muscle that does not originate from the orbital apex.

Inferior Oblique muscle

Entry portal for all nerves and vessels to the orbit

Orbital apex

Ring of fibrous tissue comprised of the origins of the 4 rectii muscle, levator palpebrae. Divides the superior orbital fissure.

Annulus of Zin

Foramen in the skull between the greater and lesser wings of the sphenoid bone.

Superior orbital fissure

Outside the annulus of Zinn. Lacrimal and frontal branch of CN V. Trochlear nerve CN IV.

Lateral

Within the annulus of Zinn. Superior and inferior divisions of CN III. Nasociliary branch of CN V. Abducens nerve. Superior ophthalmic vein.

Medial

Consists of optic nerve and artery

Optic canal

Consists of maxillary and pterygoid parts of CN V. Inferior ophthalmic vein.

Inferior orbital fissure

1st major branch of the intracranial ICA

Ophthalmic artery

Branches of the Ophthalmic artery: enters the optic nerve 8-15mm behind the globe. Supplies the inner retina.

Central retina artery

Branches of the Ophthalmic artery: supplies the lacrimal gland and upper eyelids

Lacrimal artery

Branches of the Ophthalmic artery: supplies the eyelid

Medial palpebral artery

Branches of the Ophthalmic artery: supplies the anterior segment of the eye

Long posterior ciliary artery

Branches of the Ophthalmic artery: supplies optic nerve, posterior segment of the eye.

Short posterior ciliary artery

Outer structure that protect the eyeball. Lubricates the eye surface. ______ within the tarsus.

Eyelids. Meibomian glands.

Come together at the medial and lateral canthi

Lids

Normally covers about 2 mm of the superior limbus

Upper lid

Is usually at the level of the inferior limbus

Lower lid

Exposed zone between the upper and lower eyelids. In adults: ___ mm long and _____ mm wide.

Interpalpebral fissure. 27. 8-11.

Upper eyelid is more ______ that the lower eyelid.

Mobile

Eyelid segment: thinnest in the body.

Skin

Due to insertion of levator aponeurosis near the upper border of the tarsus.

Eyelid fold

Eyelid segment: has no fat content

Subcutaneous connective tissue

Eyelid segment: punctum. Eyelashes arise from the anterior portion of the lid margin. Orifices at the meibomian gland are located along the posterior portion of the lid margin.

Lid margin

Eyelid segment: Arranged into a concentric band around the interpalpebral fissure

Orbicularis oculi muscle

Parts of OOM: inserts into the medial canthal tendon, orbital rim and corrugator supercili muscle. Sphincter like action, voluntarily controlled.

Orbital

Part of OOM: may be voluntary or involuntary z(for normal reflex blinking)

Palpebral

Eyelid segment: extension of the periosteum of the roof and floor of the orbit. Attaches to the anterior surface of the levator muscle. Provides a barrier to spread of blood or inflammation.

Orbital septum

Eyelid segment: originates from a tendon that blends with the superior rectus and superior oblique muscles at the apex of the orbit.

Levator muscle

Division of Levator muscle: produces the eyelid fold

Levator aponeurosis

Division of Levator muscle: elevates the eyelids. Innervated by superiro division of CN III.

Superior tarsal muscle (Mueller's muscle)

Eyelid segment: consist if dense CT not cartilage. Attached the orbital margin by the media. And lateral palpebral ligaments.

Tarus

Modified holocrine gland. Oily layer of the tear film.

Meibomian glands

Narrow and highly vascularized crescent shape fold of conjunctiva tissue. Roch in goblet cells. Analogous to the nictating membrane in lower animals.

Plica semilunaris

Small, fleshy, ovoid structure. Contains sebaceous glabds and fine colorless hair.

Caruncle

Located in the frontal lobe

Lacrimal gland

Lacrimal gland is divided into 2 parts by the

Levator aponeurosis

Inner to the LA

Palpebral part

Outer to the LA

Orbital part

Blood supply of the lacrimal gland

Lacrimal artery

Consist of lacrimal punctum, upper & lower canaliculi, nasolacrimal sac & nasolacrimal duct.

Lacrimal excretory system

Flow of tears is mediated by pumping of this by the orbicularis oculi muscle

Nasolacrimal sac

Opens into the nasal cavity. Valve of Hasner.

Nasolacrimal duct

Ocular motility: adducts

Medial rectus

Ocular motility: abducts

Lateral Rectus

Ocular motility: elevates, adducts & intorts

Superior rectus

Ocular motility: depresses, adducts and extorts

Inferior rectus

Ocular motility: intorts, abducts and depresses

Superior oblique

Ocular motility: extorts, abducts and elevates

Inferior oblique

Blood supply of the EOM

Muscular branches of the ophthalmic artery

Innervate the superior, medial, inferior rectus muscles and inferior oblique

CN III

Innervates the superior oblique

CN IV

Innervates the lateral rectus

CN VI

Special Senses: Ocular Flashcards

(120 cards)