20. Visual tracts

Question 1

what is the fxn of the tarsal (meibomian) glands

Answer 1

special sebaceous glands

secretion retards evaporation of tears

-if blocked ==> chalazion

Question 2

what is the name for the infectino of sebaceous glands of eyelashed

Answer 2

stye

Question 3

whaat is the lacrimal gland

Answer 3

makes tears

= made of tubuloacinar serous glands

-about 12 ducts into upper lid & tears drain into nasolacrimal duct

Question 4

what is the histological feature of palpebral & bulbar conjunctiva

Answer 4

stratified columnar epithelium w/ goblet cells

btn inner eyelid & stop lateral to cornea

Question 5

what is the ant chamber

Answer 5

space btn cornea & iris

Question 6

what is the post chamber

Answer 6

space btn post surfave of iris & ant surface of lens

Question 7

what is the vitreous chamber

Answer 7

space btn post surface of lens & neuronal retina

-filled with vitreous humor (hep maintain shapde)

=99% water w proteins & hyaluronan

Question 8

what is the fibrous tunic

Answer 8

Question 9

what is the vascular tunic/uvea

Answer 9

Question 10

what makes up the retina (internal layer)

Answer 10

Question 11

what is the corneoscleral coat

Answer 11

sclera: thick fibrous opaque layer pierced by BVs, N & optic N
cornea: refractive element of the eye; continuous with sclera = 5 layers

Question 12

what are the 5 layers of the cornea

Answer 12

corneal epithelium

bowman’s membrane

corneal stroma (avascular)

descemet’s membrane

corneal EDNOthelium

Question 13

what is the vascular coat

Answer 13

made of choroid

ciliary body

& iris

Question 14

what are the structural components of the lens

Answer 14

capsule: flexible/elastic ECM

subcapsular lens epithelium: cells on periphery proliferate & migrate to make mature lens fibers (decrease rate w/ age)

lens fibers: filler with crystallins & lose all organelles

Question 15

what is accommodation

Answer 15

adjustment of eyes for seeing object in distance

-by ciliary M (flatten/thicken)

tension of ciliary body send via zonalar polls -> change shape

Question 16

what is presbyopia

Answer 16

loss of lens elasticity w age

Question 17

characteristics of the retinal pigmented layer

Answer 17

sinmpe cuboidal epitheliial cells

=blood- neuroal retinal

Question 18

what is the neural retina

Answer 18

photosensory cells here

no lymphatics

Question 19

what visual pigments do rods and cones have

Answer 19

rods: rhodopsin
cones: iodopsin

Question 20

what is the fovea centralis

Answer 20

highest [cones]

visual acuity = sharpest (drops in outer retinal structures)

no vessels, cell bodies and axons

Question 21

what is the macula lutea

Answer 21

surrounds fovea

antioxidant properties & short wave UV filter

-protects cones of fovea

Question 22

what is the optic disc

Answer 22

at head of optic N

ganglion axons from all of retina converge & dive

=no photoreceptors = blind spot

Question 23

explain the location of the optic N

Answer 23

axons of retinal ganglion cells

penetrate choroid & sclera and travel to brain (as they pass thru sclera they become myelinated)

Question 24

what are the zones of the visual fields

Answer 24

binocular: broad central region
monocular: R/L (only seen by corresponding eye

Question 25

image formed on retina is —-

Answer 25

inverted in both lateral & vertical dimension