Term
What are the 3 tunics of the eye? |
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Definition
1. Fibrous layer of connective tissue includes the cornea and the sclera.
2. The middle vascular layer composed of the iris, ciliary body, and choroid. The iris, ciliary body and choroid make up the uveal tract.
3. The inner neural layer = retina. |
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Term
| The sclera is covered by........? |
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Definition
| The sclera is the opaque white of the eye and is covered by the transparent conjunctiva. |
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Term
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Definition
| The limbus is the transition region between the cornea and the sclera/ conjuctiva. |
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Term
| The iris muscles are innervated by the ......... nerveus system. |
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Definition
| The iris muscles are innervated by the autonomic nervous system. |
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Term
| What are some functions of the ciliary body? |
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Definition
| The ciliary body ( which is continous with the iris) produces aqueous humor and contains the ciliary muscles whic control the shape of the lens. |
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Term
| What is the function of the choroid? |
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Definition
| The choroid is a network of blood vessels that supplies the outer retinal layers. |
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Term
| The ....... ........ processes light and then transmitts visual information to the rest of the brain via the optic nerve. |
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Definition
| The nerual retina processes light and then transmits visual information to the rest of te brain via the optic nerve. |
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Term
| What two chambers of the eye contain aquous humor? |
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Definition
| The anterior chamber and the posterior chamber are contiguous through the pupil and both contain aqueous humor. |
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Term
| Name two structure of the eye which have no blood supply. What nourishes them? |
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Definition
| The cornea and lens are both avascular and are nourished by aqueous humor. |
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Term
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Definition
| The crystalline lens is located in the posterior chamber and provides aditional and adjustable refractive power. |
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Term
| What are the two portions of the fibrous tunic? |
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Definition
The two portions of the fibrous tunic are the cornia and the sclera.
The cornea is the most anterior and is continually washed by tears.
The sclera, which is continuous with the cornea anterriorly, extends back to the optic nerve. Here a portion of the sclera continues across the optic nerve forming a perforated layer through which the optic nerve fibers pass on their way to the brain. This is called the lamina cribrosa. |
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Term
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Definition
| Portion of perforated sclera, through wich the optic nerve pass on thier way to the brain |
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Term
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Definition
1.Located between the cornea and the sclera, represented by a change in charactereistic of collegen cells
2. The place where the transparent cornea meets the opaque sclera
3. Where aqueous humor in the anterior chamber is drained into the venous system at the anterior chamber angle.
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Term
| Schlemm's Canal is also called ........ |
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Definition
| The main channel collecting the aqueous humor is located at the limbus and its called Schlemm's Canal or Venosus Sclerae. |
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Term
| Where do extraocular muscles insert? |
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Definition
| The extraocular muscles insert into the sclera covering of the eye |
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Term
| Where is the sinus venosus sclerae located? |
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Definition
| The sinus venous sclerae or Schlemm's Cannal is located at the limbus |
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Term
| IRIS seperates which two chambers? |
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Definition
| The iris extends inwared from the ciliary body in front of the lens seperating the anterior and posterior chambers of the eye. |
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Term
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Definition
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Term
| Which vascular tunic layer is the most extensive region? |
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Definition
| The choroid is the most extensive region. It begins posterioly at the optic nerve and terminates anterioly at the ora serrata. This region of the uveal tract is highly vascular and provides nutrition to the photoreceptor layers of the retina from the choriocapillaris located just outside the pigmented epithelium of the retina. |
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Term
| At the ora serrata the nerve cells of the retina layer end. From this point on what cells form the innner surface of the eye? |
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Definition
| At the ora serrata the nerve cells of the retina layer end. From this point an epitheliar layer of the ciliary body forms the inner surface of the eye. The epithelial cells are derived from the same embryological layer as the retina. |
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Term
| Where do ganglion cells converge to form the optic nerve? |
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Definition
| On the inner surface of the retina, axons from the ganglion cells stream over the retina toward the optic nerve and converge at the optic disc, leaving the eye and forming the optic nerve. |
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Term
| What does the termination of the retina mark? |
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Definition
| The termination of the retina marks the anterior most extent of the choroid layer and the begining of the ciliary body. The retina extends anteriorly from the optic nerve and ends at the ora serrata. |
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Term
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Definition
| Functional blind spot, a region where no sensory cells are present |
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Term
| In the retina, what is the location of photoreceptor cell? |
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Definition
| In the retina photoreceptor cells are the outermost (towards the sclera) of the neural layers and actually point away from the light i.e. towards the pigmented layer which lies between the choroid anad the retina. |
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Term
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Definition
| The region of the retina at the posterior pole of the eye which contains the fovea and foveola. The macula has the highest visual acuity in this part of the retina due to its high density of cones. The retina is also thinnest here due to displacement of all retinal layers except for the photoreceptor cell layer. |
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Term
| The fovea contains......... |
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Definition
| The fovea contains the highest density of cone type photoreceptors but no rod type receptors. |
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Term
| What the largest compartment of the eye which fills 4/5l of the volume of the eye? |
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Definition
| The vitreus body is the largest compartment of the eye. |
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Term
| What are the boundaries of the vitreous body? |
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Definition
| The vitreous contacts the inner surface of the retina and a portion of the ciliary body. It forms a depresion which conforms to the posterior surface of the lens and also forms the posterior boundary of the posterior chamber. |
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Term
| Anterior chamber of the Eye |
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Definition
| A space posterior to the corneal endothelium and in front of the anterior surface of the iris and lens. |
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Term
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Definition
The place at the limbus where the anterior chamber narrows to an angle.
the anterior chamber angle has specialized structures that drain off aquaous humor into the venous system. Interference with drainage at the angle may result in the increase intraocular pressure of glaucoma. |
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Term
| Posterior chamber of the Eye |
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Definition
| A space anterior to the vitreous body and posterior to the posterior surface of the iris. Externaly it is bounded by the inner surface of the ciliary body. |
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Term
| Where are the cells that produce aqueous humor located? |
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Definition
| The inner layer of the cilliary body contains cells that constantly produce aqueous humor. |
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Term
| What chambers are filled with aqueous humor? |
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Definition
| The anterior and posterior chamber contain aqueous humor. Aqueous humor flows from the posterior ( where it is produced) to the anterior chamber through the space between the iris and the lens or the pupil. |
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Term
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Definition
| Astigmatism is a condition in which light rays coming from a point source are not imaged as a point. This results from the unequal refraction of light by diff meridians of the refracting element. Bc it is usually elliptic in profile,the cornea contributes to astigmatism in the eye as it refracts light and helps to focus the ray on the retina. |
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Term
| Keratometric Measurements |
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Definition
| The curvature of the ( central 3-4 mm) of the cornea can be determined by keratometric measurement to give a clinical assessment of the corneal contribution to astigmatism |
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Term
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Definition
| Regular astigmatism occurs when the longest radius of curvature and the shortest radius of curvature lie 90 degrees apart. |
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Definition
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Term
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Definition
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Term
| What is the tinnest part of the iris? |
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Definition
| the root is the thinnest part of the iris |
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Term
| Circular Contraction Folds appeare on the ........... during ........... bc............... |
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Definition
Circular contraction folds appear on the anterior iris surface, during pupillary dilation.
Circular contraction folds are evident on the anterior surface of the ciliary zone, and result from the tissue moving towared the iris root during pupillary dilation. |
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Term
| Describe the apperance of the posterior iris. |
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Definition
The posterior iris surface is fairly smooth, but when viewed with magnification, small circular furrows are evident near the pupil.
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Term
| What type of furrows are found on the posterior iris surface? |
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Definition
Radical Contraction furrows of Schwalbe are located in the pupillary zone.
Structural Furrows of Schwalbe are deeper than radial cotraction furrows. They run through the cilliary zone and continue into the ciliary body as the vallies between ciliary processes. |
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Term
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Definition
A nevus is a freckle or an area of hyperpigmintation, an accuminaltion of melanocytes. It is frequently seen in the anterior border layer.
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Term
| In Pigment Dispersion Syndrome, where are the pigment granules shed from and where do they disperse? |
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Definition
In pigment dispersion syndrome, pigment granules are shed from the posterior iris surface and are dispersed into the anterior chamber.
These pigments granules can be deposited on the iris, lens, corneal epithelium, or in the trabecular meshwork, where they might compromise aqueous out flow.
Significant pigment loss will be evident on the transillumination of the iris when the red fundus reflex shows through in the depigmented area. |
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Term
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Definition
Can be ither congeital or a sign of uveal inflamation.
Significant pigment loss will be evident on transillumination of the iris when the red fundus reflex shows through in the depigmented areas.
If congenital a disruption of the sympathetic innervation may be suspected. |
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Term
| What should be suspected with congenital heterochromia? |
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Definition
| disruption of the sympathetic innervation |
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Term
| Where does the posterior area of the ciliary body terminate? |
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Definition
The posterior area of the ciliary body terminates at the ora serrata.
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Term
| Describe differences between the anterior and posterior ciliary body. |
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Definition
| The posterior area of the ciliary body ( which terminates at the ora serrata) appears fairly flat, but the anterior ciliary body contains numerous folds or processes that extend into the posterior chamber. |
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Term
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Definition
| The ora serrata is the serrated junction between the retina and teh ciliary body. |
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Term
| The ciliary body can be divided into what two regions? |
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Definition
1. Pars plicata ( corona ciliaris) which is the wider, anterior portion containg ciliary processes.
2. Pars plana is the flatter region of teh ciliary body. it extends from the posterior of the pars plicata to the ora serrata( which is the transition between ciliary body and choroid)
The ora serrata dentate processes are elongations of the retinal tissue into the region of the pars plana. |
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Term
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Definition
| The rounded portions that lie between the teeth of the ciliary process. |
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Term
| What innervates the ciliary muscle? |
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Definition
The ciliary muscle is dually innervated by the autonomic NS (autonomic= involuntary). Parasympathetic stimullation activates muscle for contraction.
Sympathetic (4F) innervation likely has an inhibitory effect that is a function of the level of parasympathetic activity. |
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Term
| Where is the major arterial circle of the iris located? |
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Definition
| The major arterial circle of the iris is located in the ciliary stroma anterior to the circular muscle and near the iris root. |
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Term
| What becomes the neural retina? |
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Definition
| The non pigmented ciliary epithelium ( inner epithelial layer) is continious anteriorly with the posterior iris epithelium. It continues posterily at the ora serata, where it undergoes significant transformation, becoming the neural retina. |
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Term
| What are the four layers of the choroid? |
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Definition
1. Suprachoroid / Lamina Fusca
2. Choroid stroma or vessel layer
3. Choriocapillaris
4. Brush's mebrane of basal menbrane |
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Term
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Definition
| The first layer of the choroid. It contains the suprachroidal space which carries the long posterior ciliary arteries and nerves from the posterior to anterior portion of the globe. |
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Term
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Definition
The choroid stroma is a pigmented vascularized, loose connective tisuue layer.
1. Haller's layer- large diameter blood vessels
2. Sattler's layer-medium diameter blood vessels |
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Term
| The choroid vesels are innervated by the .............. nervous system. |
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Definition
The choroid vessels are innervated by the autonomic (involuntary) nervous system.
Sympathetic (4F) stimulation = vasocostriction
Parasympathetic stimulation= increased choroidal blood flow |
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Term
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Definition
Is a single layer of anastomosing fenestrated capillaries having wide lumina.
The choriocapilaris is the deepest in the macular area where it is the sole blood supply for a small region of the retina. |
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Term
| The last layer of the choroid....... |
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Definition
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Term
| What is the innervation of the iris muscles? |
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Definition
The spinchter muscles is parasympathetically innervated and is responsable for constriction of the pupil.
The dialotor is sympathetically (4F) innervated . |
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Term
| What is the significants of non pigmented ciliary epithelium? |
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Definition
The non pigmented cilliary epithelium layer ( inner layer) is metabolically active and involved in secretion of aquous humor componets and serves as a diffusion barrier between blood and aqueous.
The non pigmented cililar epithelium ( inner layer) is continious anteriorly with the posterior iris epithelium. It continues posterly at the ora serata, where it undergoes significant transformation, becoming neural retina. |
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Term
| Why are the two cilliary epithelium layers positioned apex to apex? |
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Definition
| The outer pigmented layer and the inner non pigmented layer are positioned apex to apex bc of the invagination process of neural ectoderm during optic cup development. |
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Term
| Functions of ciliary body? |
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Definition
| The ciliary body produce and secrete aqueous humor. Its muscualture causes accomodation and can affect aquoeus outflow. |
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Term
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Definition
The ability of the eye to change power and bring near objects into focus on the retina.
Contraction of the of the longitudinal fiber of the ciliary muscle pulls the choroid forward.
Contraction of the circular fibers draws the ciliary body closer to the lens.
When these muscles are fexed tension is released on zolune fibers and the lens is more spherical in shape. |
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