Histo Flashcards
what are the glands of our eyelids?
- Tarsal (meibomian) glands -> secretion stops tears from evaporating. Blocking causes chalazion
- Sebaceous gland of eyelashes -> infection causes a style
- Lacrimal gland- makes our ears
- Palpebral and bulbar conjunctiva -> thin mucus membrane (stratified columnar epithelium + goblet cells) that line inner eyelid and end lateral to cornea
three basic layers of eye
- Corneoscleral- outer layer that is penetrated by optic nerve. Made up of scar and cornea
- Vascular coat (uvea) -> middle coat is made up of the choroid, stroma of ciliary. body, stroma of iris
- Retina (inner coat that rests on choroid)
what makes up retina
epithelium of ciliary body and iris
neural retina (photoreceptors and support cells)
retinal pigmented epithelium (RPE), absorbs light, prevents refections, component of blood-retinal barrier and phagocytoses
vitreous chamber
space in between posterior surface of lens and the neural retina.
filed with vitreous humor to help maintain shape (99% water)
corneoscleral coat is what?
made up of sclera (thick layer pierced by BV. NCs and optic nerve posteriorly)
cornea
Cornea is the chief refractive element of the eye that is cont with the sclera. it has 5 layers . what are they
1. corneal epithelium: 2 Bowmans membrane 3. Corneal stroma 4. Descemet's membrane 5. corneal endothelium
what is corneal epithelium
nonketatined. stratified squamous epithelium with stem cells
2 Bowmans membrane
anterior basement membrane for epithelium
- Corneal stroma
a vascular layer of cells and stroma
- Descemet’s membrane
posterior basement membrane for the corneal endothelium
- corneal endothelium
cell type
simple squamous:
faces anterior chamber
what is this image
corneoscleral junction
what originates at the corneoscleral junction
smooth muscle
What do ciliary processes secrete?
aqueous humor
path. of humor
aqueous humor is secreted into posterior. chamber by. ciliary rocesses
fluid goes through. pupil -> anterior chamber (will give nutrients and O2 to avascular structures and maintain shape)
fluid taken up by limbus apparatus (canal of schlemm)
- components of lens
- capsule- flexible elastic ECM
- Subcapsular lens epithelium- cells on periphery migrate to make mature lens fiber cells. this decreases w age
- lens fibers- filled with crystallins and lose all orgnalles: central lens nucleus laid down during embryo development
what is the RPE
retina pigmented layer (RPE) is a layer of simple cuboidal epithelial cells that res on Bruch’s membrane of the choroid.
Actions of RPE
- serves as blood-neural rettinal layer and absorbs stray light
- Phagocytoses membranous discs shed from rods and cons
- isomerize all-trans retinal to 11-cis retinal, transporting back to photoreceptors
what are the the layers of the retina
- RPE—not part of the neural retina
- Rod and cone ends of photoreceptor cells
- Outer limiting membrane—apical boundary of
Müller cells (row of zona adherens attaching
apical ends of Müller cells) - Outer nuclear layer—cell bodies (nuclei) of
photoreceptor cells - Outer plexiform layer—processes of
rods/cones & processes of horizontal, amacrine
& bipolar cells connecting them - Inner nuclear layer—cell bodies (nuclei) of
horizontal, amacrine, and bipolar cells - Inner plexiform layer– processes of
interconnecting ganglion, amacrine, bipolar,
and horizontal cells - Ganglion layer—cell bodies (nuclei) of ganglion
cells - Layer of optic nerve fibers—processes of
ganglion cells - Inner limiting membrane—basement
membrane of Müller cells
what is the first layer light. hits in the retina?
inner limiting membrane - the BM. of muller cells
what visual pigments do rods and cones have
rhodopsin
cones have iodopsin
where are there no photoreceptors present
optic disk (optic nerve region
Retinoblastoma
autDOM disorder mutation in Rb gene on chromo 13q14.1, which suppressors tumors.
develops in kids younger than 5 yo and causes a leukocorioa (white reflection off eyes and strabismus
fovea centralis
highest concentration of cones and is AVASCULAR; surrounded by. macula lute
Describe how the lens changes shape including the functions of the ciliary muscles and ciliary zonular
fibers.
we undergo accommodation by. tension from ciliary. body transited via zonular fibers -> lens, changing its shape
what makes up organ cort
- sensory. hair cells
- inner and outer phalangeal cells (support for hair cells)
- Pilar cells (support between BM and tympanic lip
Basilar membrane vibrates with sound causing
deflection of ____ attached to tectorial
membrane—initiates neural transduction carried by
cochlear nerve
sterocilia
_____ contains saccule and utricle , each which have a macula.
vestibule
what is at the macula
cluster of hair cells with
stereocilia covered in otolithic membrane.
Otolithic membrane covered with Ca2+/carbonate protein called otoconia.
action of utricle and saccule
gravity and acceleration
Threes in the Audio-Vestibular System EXCEPT
BUT, only two maculae, capable of detecting linear acceleration in three
dimensions
Three nerves in the internal acoustic meatus
Vestibular nerve
– Acoustic nerve
– Facial nerve
