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eye and retina struc
structures of the eye and retina
| Question | Answer |
|---|---|
| these form a movable anterior covering over the eye surface | eyelids |
| what are the components of the eye lids? | fibrous core (tarsal plate), tarsal muscles and tarsal glands, palpebral part of obicularis oculi, palpebral conjuctiva, thin covering of skin |
| what are the eyelids separated by? | palpebral fissure |
| where are the eyelids united at? | medial and lateral palpebral commissures |
| what are some muscles acting on the eyelids? | levator palpebrae superioris, obicularis oculi |
| these are associated with the eyelashes and produce an oily secretion that keeps eyelids from sticking to each other | sebaceous glands |
| this is an infection of the sebaceous gland | stye |
| modified sebaceous glands located within the tarsal plate. open at the free margin of the eyelid. both sets of sebaceous glands produce lipids that help keep tears from drying out | tarsal glands |
| noninfectious lump in tarsal glands due to blockage of the ducts | chalazion |
| this consists of stratified columnar epithelium with goblet cells (unique!). its mucous secretions protect exposed part of eye and assist eyelids in moving freely over the anterior portion of the eye | conjuctiva |
| inflammation of the conjuctiva, causes can be viral, bacterial, allergic, or other | conjuctivitis |
| produces, collects, and drains lacrimal fluid from the eye. lubricates anterior surface of eye, reduces friction from eyelid movement, cleanses and moistens surface of eye, helps prevent bacterial infection through action of lysozyme | lacrimal apparatus |
| this is histologically similar to salivary glands, located in superolateral depression of orbit, continuously produces lacrimal fluid, which is washed over by eyes blinking, and fluid is transferred to the lacrimal caruncle on medial eye | lacrimal gland |
| two small openings in each lacrimal caruncle and drain fluid through lacrimal canaliculi into the lacrimal sac | lacrimal puncta |
| receives fluid from the lacrimal sac, drains fluid into lateral side of nasal cavity where it mixes with mucus | nasolacrimal duct |
| tears (lacrimal fluid) is produced here | lacrimal gland |
| lacrimal fluid is dispersed across the eye surface with this motion | blinking |
| what are the three layers of the eyeball? | fibrous tunic, vascular tunic, retina |
| what structures are included in the fibrous tunic? | sclera, cornea |
| this is the "white" of the eye and composed of dense IR CT, provides eye shape, protects internal components of the eye, attachment site for extrinsic eye muscles, and is continuous with dura mater surrounding optic nerve | fibrous tunic-sclera |
| this is a convex transparent structure forming the anterior one sixth of the fibrous tunic. outer edge adjoins sclera at the limbus, is an avascular structure that transmits light, and its nourishment comes primarily from aqueous humor and lacrimal fluid | fibrous tunic-cornea |
| what is the epithelium of the outer layer of the cornea? | stratified squamous nonkeratinized |
| what is the inner cornea composed of? | dense IR CT, highly regular with elongated fibroblasts |
| what is the inner layer epithelium of the cornea? | simple squamous endothelium that pumps fluid out of the middle layer to keep the cornea from becoming overly hydrated |
| what can be done when the cornea has damage to its endothelial layer, causing imbalance of fluid entering and exiting the cornea, resulting in it to swell and become hazy or opaque, which may lead to blindness? | corneal transplant |
| why is a corneal transplant easier to do than most other organ transplant? | the cornea is avascular, so there is a low incidence of implant rejection |
| what are the three layers of the eyeball? | iris, ciliary body, choroid, all of which are part of the vascular tunic |
| is the most anterior portion of the vascular tunic and is colored portion of the eye. made up of 2 layers of pigment forming cells, two groups of smooth muscle fibers, and vascular and nervous structures. | iris |
| black opening at the center of the iris. pupil size controlled by two smooth muscle layers, and controls the amount of light entering the eye. only one layer contracts at a time | pupil |
| this muscle has fibers resembling concentric circles, is controlled by parasympathetic division of CN 3, and constricts the pupil in response to bright light | constrictor pupillae |
| the fibers of these muscles are organized in a radial pattern, controlled by the Sympathetic division of the ANS, and dilates the pupil in response to low light | dilator pupillae muscle |
| this is immediately anterior to the choroid, and separated from the choroid by the ora serrata. is composed of ciliary muscles and ciliary processes | ciliary body |
| these are a band of smooth muscle with suspensory ligaments which extend form muscle to lens. contraction of this muscle changes tension on ligaments, altering lens shape | ciliary muscles |
| this is an elastic biconvex structure consisting entirely of cells. its cells are highly modified epithelial cells that become anucleate to form lens fibers. the anterior surface is covered by a simple cuboidal epithelium | lens |
| when the lens is flattened, what is the status of the ciliary muscle? | ciliary muscle is relaxed, and suspensory ligament is taut |
| what is the lens shape for distant vision? | flat |
| what is the lens shape for near vision (accomodation) | very round |
| this contains capillaries that secrete aqueous humor | ciliary processes |
| the anterior cavity contains what | anterior chamber and posterior chamber |
| the posterior cavity is in between what two structures? | retina and lens |
| the anterior chamber runs between what two structures? | cornea, and pupil |
| the posterior chamber runs between what two structures? | pupil, lens |
| the anterior and posterior cavities of the eye are separated by what? | lens |
| this area is filled with vitreous humor, which holds the retina in place | posterior cavity |
| this area is filled with aqueous humor | anterior cavity |
| the aqueous humor is secreted by this into the posterior chamber | ciliary process |
| excess aqueous humor is resorbed via what structure? | scleral venous sinus |
| this is the most extensive structure in the posterior region, houses vast capillaries supporting the retina, cells filled with pigment from melanocytes, and pigments absorb extraneous light leading to greater visual acuity | choroid |
| this part consists of pigmented epithelial cells and lies deep to the choroid | pigmented layer of hte retina |
| the pigmented layer of the retina is separated from the choroid by this structure | Bruch's membrane |
| these structures provide nourishment to the retina | choroid capillaries |
| this structure contains photoreceptor cells and cells involved in phototransduction. axons of ganglion cells exit the eye at the optic disc to become the optic nerve | neural layer of the retina |
| this is the yellow spot on the opthalamoscope view of the eye and is the region containing the fovea | macula lutea |
| this is the central hole of the opthalamascope view of the eye and is the area of the highest visual acuity | fovea centralis |
| this is the "blind spot" of the eye | optic disc |
Created by:
aferdo01
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