Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
117 Cards in this Set
- Front
- Back
|
Intercellular junctions
|
Join epithelial cells to one another and to adjacent tissue.
|
|
|
Zonula occludens
|
A tight junction that forms a zone or belt around the entire cells and joins it with each of the adjacent cells.
|
|
|
Zonula adherens
|
Intermediate junction, adjacent plasma membranes are separated by a narrow intercellular space that contains a specific glycoprotein, cell adhesion molecule.
|
|
|
Macula occludens or macula adherens
|
Round, button-like intercellular junctions.
|
|
|
Occluding (tight junction)
|
Outer leaflet of the cell membrane of one cell comes into direct contact with its neighbor.
|
|
|
Terminal Bar
|
Consists of zonula occludens and a zonula adherens side by side, with a the tight junction lying nearest the cell apex.
|
|
|
Desmosomes
|
Strong, spot-like attachment between cells, circular attachment plaque, and filaments extend into cellular cytoplasm.
|
|
|
Hemidesmosomes
|
Attachment of basal surface to underlying connective tissue.
|
|
|
Gap Junction
|
Cells separated by a thin, intercellular space through which small channels called connexins pass, joining the cytoplasm of two cells. These junctions allow for intercellular communication and exchange of ions from one cell to the next.
|
|
|
Regular Astigmatism
|
Principle meridians are 90 degrees apart.
|
|
|
With the Rule Astigmatism
|
Vertical meridian is steepest.
|
|
|
Against the Rule Astigmatism
|
Horizontal meridian is steepest.
|
|
|
Oblique Astigmatism
|
Steepest meridian at 45 or 135 degrees.
|
|
|
Terminal Bar
|
Consists of zonula occludens and a zonula adherens side by side, with a the tight junction lying nearest the cell apex.
|
|
|
Irregular astigmatism
|
Principle meridians are not 90 degrees apart (not common).
|
|
|
Desmosomes
|
Strong, spot-like attachment between cells, circular attachment plaque, and filaments extend into cellular cytoplasm.
|
|
|
Hemidesmosomes
|
Attachment of basal surface to underlying connective tissue.
|
|
|
Epithelium
|
Stratified squamous, surface layer, wing cell layer, basal layer.
|
|
|
Gap Junction
|
Cells separated by a thin, intercellular space through which small channels called connexins pass, joining the cytoplasm of two cells. These junctions allow for intercellular communication and exchange of ions from one cell to the next.
|
|
|
Regular Astigmatism
|
Principle meridians are 90 degrees apart.
|
|
|
With the Rule Astigmatism
|
Vertical meridian is steepest.
|
|
|
Against the Rule Astigmatism
|
Horizontal meridian is steepest.
|
|
|
Oblique Astigmatism
|
Steepest meridian at 45 or 135 degrees.
|
|
|
Irregular astigmatism
|
Principle meridians are not 90 degrees apart (not common).
|
|
|
Epithelium
|
Stratified squamous, surface layer, wing cell layer, basal layer.
|
|
|
What stem cells are basal cells replenished from?
|
Limbus
|
|
|
Bowman's Layer
|
Composed of irregular connective tissue, acellular, transitional layer.
|
|
|
What is composes the Stroma?
|
Regular dense connective tissue, collagen fibers, cells (fibroblasts/keratocytes), and ground substance.
|
|
|
Descemet's membrane
|
Could regenerate, composed of dense connective tissue, acellular, elastic properties, highly resistant to proteolytic enzymes, basement of endothelium, and Schwalbe's line.
|
|
|
Schwalbe's line
|
Descemet membrane ends, circular line that end at limbal.
|
|
|
Endothelium
|
Single layer of specialized epithelium, endothelial mosaic, 70-80% of cells are hexgonal, does not replicate, intercellular junctions (lateral interdigitations, gap junctions, occluding junctions, no hemidesmosomes).
|
|
|
Hassall-Henle bodies
|
Thickening in Descemet's membrane that bulge into the anterior chamber, located near the corneal periphery, increases with age.
|
|
|
Corneal guttata
|
Deposits of basement membrane in central cornea and are indicative of endothelial dysfunction.
|
|
|
Sclera
|
Located posterior 5/6 of globe, composed of dense irregular connective tissue, avascular, continuous with corneal stroma.
|
|
|
Episclera
|
Located outer to sclera and composed of loose vascular connective tissue and blood vessels.
|
|
|
Tenon's Capsule
|
Dense connective tissue capsule outer to episcleral.
|
|
|
Bulbar conjunctiva
|
Located in outer to Tenon's capsule and continuous with palpebral conjunctiva at fornices, composed of stratified non-keratinized columnar epithelium (goblet cells) and stroma (immunologically active, blood vessels and lymphatics).
|
|
|
Limbus
|
Located annular region surrounding corneal periphery (1.5-2mm in width), Bowman's to termination of Descemet's, posterior scleral spur to conjunctiva surface and perpendicular to it, external scleral sulcus, and internal scleral sulcus.
|
|
|
Palisades of Vogt
|
Grey "peg", location of corneal and conjunctival stem cells.
|
|
|
What happens when there's a hypertonicity?
|
Tear film draws H2O from cornea.
|
|
|
What causes corneal edema with epithelial damage?
|
Loss of zonula occludens, localized area of swelling and haziness, abrasion, and injury..
|
|
|
What causes corneal edema with endothelial damage?
|
Loss of active pump mechanism, disease, surgery, injury, poorly fit contact lens may allow stagnation of tears, formation of guttat.
|
|
|
Hypoxic conditions
|
Concntration of lactate increases, osmotic balance changes, induces stromal edema, and termed metabolic edema.
|
|
|
What are the two affects of corneal edema?
|
Acidification and Neovascularization
|
|
|
What are some treatments for corneal edema?
|
Eliminate cause and temporary clearing with hypertonic solution of glycerin instillation.
|
|
|
What attaches the iris to the ciliary body?
|
The iris root.
|
|
|
Where is the pupillary ruff located?
|
Anterior to the root.
|
|
|
Pupillary
|
Portion surrounding the pupil.
|
|
|
Ciliary
|
From collarette to root.
|
|
|
Anterior Border Layers
|
Composed of connective tissue (fibroblasts and melanocytes).
|
|
|
Fibroblasts
|
Flattened cells with processes, extend and interconnect.
|
|
|
Melanocytes
|
Below, contain melanin.
|
|
|
Stroma
|
Composed of loose connective tissue, collagen fibers arranged in trabeculae, cells (pigmented: Melanocytes and Clump cells, non-pigmented: Fibroblasts).
|
|
|
What structures are located within iris stroma?
|
Blood vessels and sphincter muscle.
|
|
|
Major circle of iris
|
Origin of iris arteries (in ciliary body)
|
|
|
Minor circle of iris
|
Incomplete circular vessel within iris stroma.
|
|
|
Sphincter muscle
|
Circular muscle surround pupillary ruff, located within the stroma, composed of smooth muscle, and constrict pupil.
|
|
|
Anterior iris epithelium (myoepthelium)
|
Muscle of epithelial tissue, apical, basal = dilator (smooth muscle fibers), dilator muscle (located from root to midpoint below sphincter, and dilate).
|
|
|
Posterior iris epithelium
|
Pigmented columnar, basal aspect lines posterior chamber. (Two layers of epithelium are positioned apex-to-apex joined to each other via desmosomes)
|
|
|
Innervation of iris musculature
|
Sphincter (parasympathetic) and Dilator (sympathetic)
|
|
|
Anterior Iris Surface
|
Crypts are located on both sides of the collarette (Fuchs' crypt and near the root (peripheral crypts). Allow the aqueous quick exit and entrance into spaces in the iris stroma as the volume of the iris changes with iris dilation and contraction.
|
|
|
Circular contraction folds
|
Result from tissue moving toward the iris root during pupillary dilation.
|
|
|
Posterior iris surface
|
Redial contraction furrows are location in the pupillary zone, and the deeper structural furrows run throughout the ciliary zone and continue into the ciliary body as the valleys between the ciliary processes.
|
|
|
Iris synechia
|
An abnormal attachment between the iris surface and another surface.
|
|
|
Posterior synechia
|
The posterior iris surface is adherent to the anterior lens surface.
|
|
|
Anterior synechia
|
The anterior iris surface is adherent to the corneal endothelium or the trabecular meshwork.
|
|
|
What is the area between ciliary processes called?
|
Valleys of Kuhnt.
|
|
|
Supraciliaris
|
Connect tissue layer bands of collagen, oblique oriented, adjacent to sclera, loose connective tissue, arrangement of these bands allows the ciliary body to slide against the sclera without detaching from or stretching the tissue.
|
|
|
Ciliary muscle
|
Composed of smooth muscle fibers oriented in longitudinal, radial, and circular directions.
|
|
|
Longitudinal muscle fibers (of Brucke)
|
Lie adjacent to the supraciliaris and parallel to the sclera. Originates on the scleral spur and insert in star-shaped processes, stellate into choroid.
|
|
|
Radial fibers
|
Wider, shorter interdigitating Vs that originate at the scleral spur and insert into the connective tissue near the base of the ciliary processes.
|
|
|
Mullers annular muscle (inner)
|
Formed of circular muscle bundles with a sphincter-type action and fibers are located near the major circle of the iris.
|
|
|
Ciliary Stroma
|
Highly vascular loose connective tissue, lies between the muscle and the epithelial layers and form the core of each of the ciliary processes.
|
|
|
Ciliary epithelium
|
Two layers of epithelium, positioned apex to apex, cover the ciliary body and line the posterior chamber and part of the vitreous chamber.
|
|
|
What is the outer pigmented continuous with?
|
Anterior with iris epithelium and posterior with retinal pigment epithelium.
|
|
|
What is the inner non-pigmented continuous with?
|
Anteriorly with the posterior iris epithelium and continues posteriorly at the ora serrata, where it undergoes significant transformation becoming neural retina.
|
|
|
Pigmented ciliary epithelium
|
Intercellular junctions (gap junction, communication between cells, cubodial cells) and role in aqueous production.
|
|
|
Non-pigmented ciliary epithelium
|
Cubodial in plicata and columnar in planar, intercellulat junctions (desmosomes and zonular occludens), produces and secretes aqueous humor.
|
|
|
Blood-aqueous barrier
|
Selectively controlled substance secreted as aqueous.
|
|
|
Choroid
|
Located between the sclera and retina, extent from optic disc to ora serrata.
|
|
|
Suprachoroid lamina
|
Continuous with supraciliaris and composed of oblique collagen layer for sliding motion, contain "perichoroidal space) potential space.
|
|
|
Choroidal stroma
|
Continuous with ciliary body stroma and contains Haller's layer (large-lumened vessels), Sattler's layer (medium-lumened vessels) and vortex veins.
|
|
|
Choriocapillaris
|
A single layer of anastomosing, fenestrated capillaries having wide lumina.
|
|
|
Bruch's membrane
|
- BM of choriocapillaris
- Outer collagenous zone - Elastic layer - Inner collagenous zone - BM of Retinal Pigmented Epithelium |
|
|
What is the function of the choroid?
|
Provides nutrients to and eliminates waste from outer retina and absorbs excess light.
|
|
|
Drusen
|
A pin point dot in choroid, cause accumulation of waste matter which displace retina, yellow-white dots/spots in retina.
|
|
|
Anterior chamber angle
|
Located in internal scleral sulcus, junction of cornea and uvea, and function in aqueous exit.
|
|
|
Scleral spur
|
Piece of sclera trabecular meshwork connect, located at posterior edge of internal scleral sulcus, and function in anchor for trabecular meshwork and origin of ciliary muscle.
|
|
|
Trabecular meshwork
|
Located encircles circumference of anterior chamber, triangular in cross section, apex at Schwalbe's line and base at scleral spur.
|
|
|
Corneoscleral meshwork
|
Sheets of trabecular meshwork that attach to scleral spur.
|
|
|
Uveal meshwork
|
Sheets attach to ciliary body.
|
|
|
What makes up the trabecular sheet?
|
Inner core of collagen, surrounded by ground substance, and covered with endothelium.
|
|
|
Canal of Schlemm
|
Outer to trabecular meshwork, circular venous channel, intercellular junctions in outer wall contains endothelium jointed by zonular occludens and inner wall closer to TM, jointed by tight junction, collect aqueous and empty into the venous system.
|
|
|
Juxtacanlicular Connective Tissue
|
Cribriform layer, located in inner wall of canal of Schlemn and sheet of TM, and contain cells with phagocytic properties.
|
|
|
Posterior embryotoxin
|
Found in 15-20% of population, congenital hypertrophied Schwalbe's line, projects as a glistening ridge, and is sometimes pigmented.
|
|
|
Posterior Chamber
|
Location is annular area posterior to iris surrounding lens equator and partitioned by Canal of Hannover and Canal of Petit.
|
|
|
Canal of Hannover
|
Lens to ciliary body
|
|
|
Canal of Petit
|
Posterior zonule to vitreal face.
|
|
|
Aqueous Humor
|
Aqueous bathes posterior cornea and anterior lens, provides nutrients, and carries metabolic waste away.
|
|
|
Aqueous exits from anterior chamber via which two pathway?
|
Trabecular meshwork (Schlemm's Canal) and uveoscleral flow.
|
|
|
Aqueous flow through Trabecular meshwork (Schlemm's canal)
|
Passive passage through meshwork, through juxtacanalicular tissue (highest resistance to outflow), and passes through giant vacuoles in endothelial cells of Schlemm's canal.
|
|
|
Exit from Schlemm's canal:
|
Schlemm's canal, external collector channels, deep scleral plexus, intrascleral plexus, episcleral, and conjunctiva veins.
|
|
|
Aqueous veins of Ascher
|
Empty into episcleral or conjunctival vein.
|
|
|
Uveoscleral flow
|
Absorbed into face of ciliary body and then into veins of ciliary body or sclera, unconventional outflow, involves just a small amount of aqueous (ciliary body face).
|
|
|
How does diffusion of substances cross epithelial membranes?
|
Occurs down a concentration gradient.
|
|
|
How does ultrafiltration of substances cross epithelial membranes?
|
Flow across the epithelium, movement can be enhanced by increasing hydrostatic driving force.
|
|
|
How does active transport of substances cross epithelial membranes?
|
A pump mechanism and utilizes cellular energy as solutes are moved against a concentration gradient.
|
|
|
True or False: in order to maintain IOP in a relatively small range a constant rate of production of aqueous is balanced by an equal constant rate of exit.
|
True
|
|
|
Production (Inflow) dependent on 3 factors:
|
1. Ultrafiltration from BV's in ciliary processes, which is dependent on: Hydrodynamic pressure head (Pcap - PIOP)
|
|
|
Aqueous exit (outflow) is dependent on 3 factors:
|
1. Hydrodynamic pressure head (PIOP - Pe)
|
|
|
Blood-aqueous barrier
|
- Fenestrated CB capillaries permit large molecules to exit blood
- ZO joining cells of the non-pigmented epithelium - Non-fenestrated iris capillaries prevent large molecules from entering aqueous |
|
|
Blood-retinal barrier
|
- Fenestrated in choriocapillaris
- ZO in RPE - Non-fenestrated retinal capillaries |
|
|
Dark current
|
Inner segment membrane continually pumps Na+ out of photoreceptor creating a negative potential on the inside of the cell, outer segment membrane is permeable to Na+ it continually leaks back in and neutralizes much of the negativity, in this state the photoreceptor is inactive
|
|
|
Light and Dark on photoreceptors
|
- ON bipolar depolarizes to light on (metabotropic receptors)
- OFF bipolar depolarizes to light off (ionotropic receptors), - Rods are only connected to ON bipolar |
|
|
Retinal detachment
|
Between the RPE and photoreceptors
|
|
|
Dot and blot hemorrhages
|
Inner Nuclear Layer
|
|
|
Flame-shaped hemorrhages
|
Nerve Fiber Layer
|
