Week 5: Orbit and Eye

The ___ ___ is defined by the area of the face overlying the orbit and eyeball, including the upper/lower eyelids and lacrimal apparatus

Orbital region

List the accessory visual structures

Orbital fascia, conjunctiva, lacrimal apparatus, eyelids, extra-ocular muscles, nerves and vessels

List the bones that comprise the orbital region

Frontal, zygomatic, maxilla, nasal, sphenoid, ethmoid, lacrimal, palatine

The base, 4 walls, and apex of the orbit form a ___ shape

Conical

Base of orbit

Orbital margin

Superior wall of orbit

Orbital part of frontal bone, lesser wing of sphenoid

Medial wall of orbit

Orbital plate of ethmoid, frontal process of maxilla, sphenoid, lacrimal

Inferior wall of orbit

Maxilla, zygomatic, palatine

Lateral wall of orbit

Frontal process of zygomatic and greater wing of sphenoid

Apex of orbit

Optic canal

The optic canal lies in the ___ ___ of the ___ bone, medial to the ___ ___ ___

Lesser wing, sphenoid, superior orbital fissure

The periosteum that lines the bones of the orbit is known as ___

Periorbita

At the optic canal, the periorbita is continuous with the ___ layer of the ___ ___

Periosteal, dura mater

Over the orbital margins and through the IOF, the periorbita is continuous with the ___

Pericranium

At the orbital margins, the periorbita is continuous with the ___ ___

Orbital septa

The periorbita is continuous with the fascial ___ of the ___-___ muscles

Sheaths, extra-orbital

The periorbita is continuous with the orbital ___ that forms the ___ of the eyeball

Fascia, sheath

The eyelids protect the eyeball from injury and excess light by spreading ___ ___

Lacrimal fluid

What is the name of the mucous membrane on the inner eyelid?

Palpebral conjunctiva

What is the name of the mucous membrane on the surface of the eyeball?

Bulbar conjunctiva

The areas where the palpebral and bulbar conjunctiva meet and form a pocket are known as the superior and inferior ___ ___

Conjunctival fornices

The superior and inferior ___ form the skeleton of the eyelids. Which muscle (and which part) are superficial to them?

Tarsi, palpebral part of orbicularis oculi

The ___ ___ are deep to the tarsi and produce ___ secretions that lubricate the edges of the eyelids, preventing them from ___ ___ when they close

Tarsal glands, lipid, sticking together

The eyelashes are known as ___ and contain ___ ___ at their bases

Cilia, ciliary glands

The angles of the eyes are known as medial/lateral ___ ___

Palpebral commisures

What structures attach the tarsi to the medial and lateral margins of the orbit?

Palpebral ligaments

The ___ gland secretes lacrimal fluid from the parasympathetic secretomotor effects of the ___ nerve via the ___ ganglion

Lacrimal, facial, pterygopalatine

Lacrimal fluid contains an enzyme called ___ and provides ___ and dissolved ___ to the cornea

Lysozyme, nutrients, oxygen

The lacrimal ___ acts like a dam in the medial ___ to allow the lacrimal lake to fill with ___

Caruncle, canthus, tears

The extra flap of the bulbar conjunctiva that serves as the floor of the lacrimal lake is known as the ___ ___

Plica semilunaris

The lacrimal ___ on the lacrimal ___ drains tears into the lacrimal ___

Punctum, papilla, canaliculi

The lacrimal canaliculi drain into the lacrimal ___ and then into the ___ ___, which conveys fluid to the ___ ___ ___

Sac, nasolacrimal duct, inferior nasal meatus

Tears are stimulated by parasympathetic impulses from the ___ nerve

Facial

Pre-synaptic fibers from the facial nerve travel along the ___ ___ nerve to the ___ ___ ___ towards the ___ ganglion

Greater petrosal, nerve of the pterygoid canal, pterygopalatine

What is the post-synaptic pathway to the lacrimal nerve?

Maxillary to pterygopalatine to zygomatic to zygomaticotemporal to lacrimal

The lacrimal nerve comes from the ___ nerve

Ophthalmic

What are the three layers of the eyeball from superficial to deep?

Fibrous, vascular, inner

The fibrous layer includes the ___ and ___

Sclera, cornea

The sclera provides attachment for the intrinsic and extrinsic ___ of the eye, and the cornea composes the anterior ___/___ of the eye and is completely ___

Muscles, 1/6, avascular

The vascular layer of the eyeball is composed of what three structures?

Choroid, ciliary body, iris

The choroid lies between the ___ and the ___ and supplies ___ to both. It causes ___ eyes in a photo

Sclera, retina, oxygen, red

The ciliary body is a ring-like thickening of the ___ layer posterior to the ___ junction. It provides an attachment for the lens via the ___ ligaments

Vascular, corneoscleral, suspensory

Ciliary ___ secrete aqueous ___ that fills the anterior compartment of the eyeball

Processes, humor

The iris lies on the ___ surface of the lens and the pupil transmits ___ into the eye

Anterior, light

Sphincter pupillae is ___ stimulated through the ___ ganglion, and dilator pupillae is ___ stimulated

Parasympathetically, ciliary, sympathetically

The inner layer of the eyeball contains the ___, which is composed of the ___ and ___ parts

Retina, optic, nonvisual

What are the layers of the optic part of the inner layer?

Neural, pigmented, optic disc, macula lutea

The neural layer contains ___, the two types being ___ and ___

Photoreceptors, rods, cones

The pigmented layer is composed of a ___ layer of cells that reinforces the light-absorbing property of the ___ in (increasing/decreasing) the scattering of light in the eyeball

Single, choroid, decreasing

The optic disc (does/does not) contain photoreceptors and contains sensory fibers and vessels from the ___ nerve

Does not, optic

The macula lutea is mostly filled with ___, and the ___ ___ is 100% cones and has the most ___ vision

Cones, fovea centralis, acute

The nonvisual part is an anterior continuation of the ___ layer and a layer of ___ cells. It extends over the ___ ___ and posterior surface of the ___ to the ___ margin

Pigmented, supporting, ciliary body, pupillary

Describe the order of refractive media within the eyeball

Cornea to aqueous humor to to lens to vitreous humor

The ___ is the primary refractive media

Cornea

The corneal reflex is innervated by the ___ nerve

Ophthalmic

The lens is anchored by the suspensory ligament of the lens, otherwise known as ___ ___

Zonular fibers

The ___ muscle changes the shape of the lens, a process known as ___

Ciliary, accomodation

The lens receives parasympathetic innervation through the ___ nerve

Oculomotor

Sphincter-like contractions of the ciliary muscle (dilate/constrict) the pupil, (thicken/thin) the lens, and are suited for (near/far) vision

Constrict, thicken, near

With no nerve stimulation, diameter of the ciliary muscle is (larger/smaller) and the lens is (thicker/thinner), which is best suited for (near/far) vision

Larger, thinner, far

The anterior compartment of the eyeball is composed of the ___ and ___ chambers

Anterior, posterior

What structures does the anterior chamber lie between?

Cornea and iris/pupil

What structures does the posterior chamber lie between?

Iris/pupil and ciliary body

Aqueous humor in the anterior compartment drains through ___ ___ ___, otherwise known as the canal of ___

Scleral venous sinuses, Schlemm

If drainage of AH is slowed or stopped, the anterior segment increases in pressure, leading to ___

Glaucoma

The posterior compartment is filled with ___ ___ in the posterior __/__ of the eyeball

Vitreous humor, 4/5th

The posterior compartment transmits ___, holds the ___ in place, and supports the ___. We are born with the amount of vitreous humor we need for an entire ___

Light, retina, lens, lifetime

Each eye contains ___ muscles that moves the eyeball in ___ axes

7, 3

What membrane covers the surface of the optic nerve?

Pia mater

What are the three branches of the ophthalmic nerve?

Frontal, nasociliary, lacrimal

What are the two branches of the frontal nerve? They supply ___ innervation to the ___

Supratrochlear, supraorbital, sensory, forehead

The lacrimal nerve carries ___ and ___ fibers to the lacrimal gland

Sympathetic, parasympathetic

What are the four branches of the nasolacrimal nerve? They supply ___ innervation to the ethmoidal ___ ___, paranasal, ___, and ___ area of the forehead

Long ciliary, anterior ethmoidal, posterior ethmoidal, infratrochlear, sensory, air cells, sinuses, glabellar

The ciliary ganglion is located between the ___ ___ and ___ ___

Optic nerve, lateral rectus

The ciliary ganglion receives fibers from the ___ nerve, presynaptic fibers from the ___ nerve, and postsynaptic fibers from the ___ ___ plexus via the ___ ___ ganglion

Nasociliary, oculomotor, internal carotid, superior cervical

___ ___ nerves arise from the ciliary ganglion to pierce the sclera and carry sympathetic and parasympathetic fibers to the ___ ___ and ___

Short ciliary, ciliary body, iris

The post-synaptic fibers from the ciliary ganglion are carried by the ___ ___ nerves

Short ciliary

The first branch of the ICA is the ___ artery

Ophthalmic

List the branches of the ophthalmic artery

Central retinal, supraorbital, supratrochlear, lacrimal, dorsal nasal, short posterior ciliary, long posterior ciliary, anterior ethmoidal, posterior ethmoidal

The main two sources of venous drainage from the orbit are the superior and inferior ___ veins

Ophthalmic

The ophthalmic veins pass through the ___ to enter the ___ sinus

SOF, cavernous

The inferior ophthalmic veins pass through may also drain into the ___ plexus

Pterygoid

The ___ ___ vein usually directly enters the cavernous sinus

Central retinal