eye histo Flashcards
what are tarsal glands
*meiobomian
special sebaceous glands on inside of the eyelid.
-secrete oils that’s help slow down the evaporation of tears in order to moisten the eye
-occlusion of this gland -dry eye
-irriatation of gland = chalazion
what are the layers of the retina
*starting from choroid out (bruchs membrane)
1. retinal pigmented epithelium
2. ends process of rods and cones
3. outer limiting membrane (apical muller cells)
4. outer nuclear layer -bodies of rods and cones
5. outer plexiform layer- amacrine, horizontal, bipolar processes
6. inner nuclear layer - amacrine, horizontal and bipolar bodies
7. inner plexiform layer - interconnecting ganglion processes
8. ganglion layer - ganglion cells bodies
9. optic nerve fiber layer - ganglion proceses
10 . inner limiting membrane (basement membrane of muller cells )
what are the 5 layers of the cornea
- corneal epithelium ( non-keratinized stratified squamous)
- Bowmans membrane
- corneal stroma (avascular but lots of afferent nerves)
- Descemets membrane (thick)
- corneal endothelium (simple squamous facing anterior chamber)
what are the layers of the lens
- capsule layer (basil lamina)
- lens sub capsular epithelium (where new forming lens fibers are being made to become mature)
- lens fiber (matured towards the center; no organelles, filled with crystallin)
what is presbyopia
los of lens elasticity that causes problems with near and far sightedness
-happens as we age
where is the highest concentration of cones
fovea
surrounded by macula
what is the cupullla? where is it located
-in the ampulla of the semicircular canals there is a gelatinous like cap called the cupola, hair cells with cilia are attached at ends and send signals the the vestibular N. when fluid moved the cupola in repose to acceleration
what is a retinablastoma, and how does it present ?
- tumor in the retina of the eye
- caused by a mutation of RB gene (tumor suppressor for G1–> S phase)
presentation: leukocria (white reflection off retina) strabismus (misalignment of the eye) and occurs before the age of 5
what is the limbus apparatus
*site of corneal steam cells
-the trabecular network and canal of schlemm that drains the aqueous humor
[canal of schlemm also does vascular venous return]
what are the glands on the eyelashes
- Zeis sebaceous glands
- infection of these causes a “stye”
what are the functions of the pigmented retina
- absorb stray light
- prevent reflections
- phagocytoses of discs from old rods and cones
- isomerizes trans-retinal to 11-cis retinal
- blood-retinal barrier
what divides the cochlear canal into the scala media, tympani, and vestibuli
the cochlear duct (which has endolymph) in the scala media, and surrounded scalas
what is the spiral ligament, spiral ganglion, and outer spiral layer
- spiral ganglion send nerve fibers from the organ of corti to the cochlear nerve for hearing.
- spiral ligaments hold the organ of corti in place laterally
- outer spiral lamina is the boney covering supporting the tectorial membrane and the spiral ganglion
where is the corticlymphatic space
in the cochlea
organ of corti
what is composed in organ of corti
- pillar cels (support on basilar membrane)
- interphalangeal cells (hair support cells)
- 3 outer hair cells, 1 inner hair celll projecting cilia to the tectorial membrane which will bend by tectorial membrane movement to send signals to the cochlear n
what is the cell type lining the outside, inside of eyelid and cornea
outside eyelid-stratified squamous
inside- stratified columnar with goblet cells
cornea - stratified squamous
where are lacrimal glands? and what are there specifics
- under the palpebral conjunctive of the eyelid
- tubuloacinar serous gland
- secretes tears
- 12 ducts drain into glands of lid, then the lacrimal duct drains into the nasolacrimal duct
what is the main refractor of the eye
cornea
what are the 2 layers of the choroid
inner vascular layer - choriocapilllary
outer Bruch membrane (ECM layer where the pigmented retina sits)
what part of the eye does extrinsic muscles attaches ? is thick / fibrous/ opaque layer, with blood vessels and optic nerve piercing through it
sclera
-dense CT
what surrounds the macula of the saccule and utricle
otolithic membrane surrounding the hair cells and stjerelcilia that gives moved by the otolithic crystals that help sense gravity
what is the stria vascular and where is it located
- maked endolymph
- is located in the lateral wall of the scala media
what part of the vascular layer absorbs scattered light
choroid
what layer of the eye has photoreceptors and support cells
neural retina
