Eye Test Three Flashcards
What is the Macula Lutea?
Yellow region surrounding the fovea, has the highest visual acuity
What is the fibrous tunic?
Slcera and cornea
What is the vascular tunic?
Choroid, Ciliary Body, and Iris
What is the inner tunic?
Retina
What is the Episcleral layer?
- Outer layer of the sclera
- loose collagen and elastic fibers
- Very vascular
- Attaches eyelid lining to sclera
What is the sclera proper?
- Made up of interlacing collagen fibers
- Attachment site for tendons of extrinsic eye muscles
- Collagen bundles are parallel to outer surface of slcera
What is the Lamina cribosa?
- Perforated disc of sclera
- Pass through for optic nerve
Posteriorly the slcera is continuous with what?
Dural covering of the optic nerve
Layers of the cornea?
- Corneal epithelium
- Bownan’s Membrane
- Corneal stroma
- Descements membrane
- Corneal endothelium
Describe the corneal epithelium.
- Stratified non keratinized squamous epithlelium
- HIgh mitotic activity in basal layer
Describe Bowmans Membrane.
- Part of fibrous tunic of cornea
- Acellular layer sepatates epithelium from stroma
- Randomly arranged collagen
Describe the Corneal stroma.
Thin layers of ordered arrays of collagen fibers
Describe Descemet’s Membrane.
- Part of the fibrous tunic Cornea layers
- Acellular layer of collagen bundles
- Separates stroma from endothelium
Describe the Corneal endothelium.
Single layer of large squamous cells
Identify.
- Corneal endothelium
- Descemet’s Membrane
- Corneal Epithelium
- Bowman’s Layer
- Stroma
Vascular Tunic?
Choroid and Ciliary body
What is the Choroid?
Part of the vascular tunic
- Extends anterior to ora serrata of retina
- Highly vascularized with loose CT
- provides nutrients to outer layer of retina, contains melanocytes, forms choriocapillary network
- Bruch’s (Glassy) Membrane: acellular fused basal laminae of choripcapillaris and pigmented retinal epithelium
What is the Ciliary Body?
Part of the vascular tunic:
- Wedge shaped expansion of the choroid periphreal to lens covered by a double layer of cells
- Innermost layer is continuous with pigmented retina
- Surface layer is from sensory retina
- Produces Aqueous humor
- Suspensory ligaments behind lens
- Ciliary muscles innervated by parasympathetic
If the lens is flattened what kind of vision does that help?
Far vision
If the lens becomes thicker how does that affect vision?
Good for close vision
What surface layer of cells produces aqueous humor in the Ciliary Body?
Nonpigmented layer of cells
Describe the Iris.
Part of the vascular tunic:
- Anterior to the lens and separates the anterior and posterior chambers
- Surrounds pupil
- Melanocytes
- Double layer of epithelium
- Inner is pigmented
- Outer is radially oriented myofilaments sympathetic innervation
- Concentric layer of myofilaments is parasympathetic innervation
What are the two divisions of the retina divided by the Ora Serrrata?
- Photosensitive region posterior to the ora serrata (largest)
- Nonphotosensitive region anterior to ora serrata
Describe the photosensitive region of the retina.
- Optic disc: area wherr optic nerve exits, also the “blind spot” as ther eare no photoreceptors
- Fovea Centralis: most acute are of vision only has cone type receptors
Descibe the non photosensitive region of retina?
Consists of two cell layers covering the iris ciliary body and ciliary processes
Chambers of the eye?
Anterior chamber
Posterior Chamber
Vitreal Chamber
Where is the anterior chamber?
Posterior to cornea and anterior to iris
Where is posterior chamber?
Posterior to iris and anterior to lens
Where is the vitreal chamber?
Posteior to lens contains vitreous body, gelatinous mass
What is Glaucoma?
Increased intraocuar pressure due to compromised drainage of the aqueous humor from anterior chamber
Identify.
- Choroid
- Pigmented Epithelium
- Outer nuclear layer
- Inner nuclear layer
- Ganglion cell layer
Identify.
- Inner and outer segments of rods and cones
- Outer plexiform layer
- Inner plexiform layer
- Axons of ganglion cells
- Internal limiting membrane
Layers of the retina?
- Pigmented epithelium
- Inner/outer seg. of rods and cones
- external limiting membrane
- outer nuclear layer
- outer plexiform layer
- inner nuclear layer
- inner plexiform layer
- ganglion cell layer
- optic nerve layer
- internal limiting membrane
Pigmented epithelium of retina?
Adjacvent to choroid derived from outer layer of optic cup
Inner and outer segments of rods and cones on the retina?
- Outer segment consists of rhodopsin containing lamellae
- Inner segment consists of areas of rods and cones possessing mitochondria RER golgi and glycogen
External limiting membrane of retina?
- Area at junction of inner and outer segments of rods anc cones and outer nuclear layer
- Includes adherens junctions between rods and cones and mueller cells
Outer nuclear layer of retina?
Cell bodies of rods and cones
1st order neurons
Outer plexiform layer?
Area of synapses between axons of rods and cones and dendrites of bipolar neurons and horizontal cells
Inner nuclear layer of retina?
Cell bodies of biopolar cells horizontal cells ama rine cells and mueller cells
2nd order neurons
Inner plexiform layer of retina?
Area of synapses between axons of bipolar cells and endrites of ganglion cells
Ganglion cell layer of retina?
Cell bodies of ganglion cells
3rd order neurons
Optic enerve layer of retina?
Axons of ganglion cells
Internal limiting membrane of retina?
Terminations of mueller cell processes and their basement membranes
Pigmented Cells of the retina?
- Synthesize melanin
- Phagocytose and degrade lamellae from rods and cones
- connect through thight junctions to form Blood-Retina barrier
- Esterify vitamin A
What do horizontal cells and bipolar cells do?
Horizontal: interneurons that connect rods and cones with each other and bipolar cells
Bipolar: conducting neurons that synapse with rods and cones
What do amacrine cells do?
Interneurons that connect ganglion cells and bipolar neurons
What do mueller cells do?
- Neuroglial cells that extend throughout retina
- Form external limiting membrane via zonulae adherens betweeen mueller cells and rods and cones
- Internal limiting membrane is formed by BM of these
What do ganglion cells do?
Conducint neurons whose axons form fibers of the optic nerve
What is the Fovea Centralis?
Depression of visual axis
Has highest density of cones lacks rods and capillaires
What is the optic disc?
Lacks photoreceptors
Point where ganglion cell axons turn into optic nerve
Blind spot of retina
What photopigment do Rods and Cones use?
Rhodopsin and Iodopsin
Describe the general architecture of photoreceptors.
Inner segment containing mitochondria and other organelles
Cell body contaiing nucleus and short axons
Outer segment containing modified cilium connected by stalk to inner segment and site of stacks of discs containing photoreceptors
What is the difference in discs between rods ancd cone cells?
In cone cells disks sre attached to the cell membrane and in rod cells they detatch from the membrane
What photoreceptor is sensitive to low light intensity and responsible for balck and white vision?
Rods
What photoreceptor is responsible for high intensity light sensitivity and color vision?
Cones
Describe the lens.,
Capsule: insesrtion for suspensory ligament
Anterior epithelium: simple cuboiudal cells
Lens nucleus: devoid of nucleus and organelles composed of lens cells that mature into fiber like structures, also filled with crystalline proteins
Describe the eyelid.
Anterior surface is covered with skin
Glands of Zeiss: sebaceous glands
Glands of Moll: Sweat glands which open into eyelash follicles
Palpebral fascia: fibrous core of eyelids, Meibomian glands sebaceous glands not associated with hair- keeps normal tear film in eyes
Palpebral conjunctiva: stratified columnatr or squamous epi with goblet cells lines inner surface of eyelids
Identify
- Tarsal glands
- Orbiculairs muslce
