Ocular anatomy and histology part 4-6

what is the vascular tunic also known as

the uvea

what is the function of the iris in the vascular tunic

acts as a blood aqueous barrier

what muscle of the iris causes it to constrict the pupil

sphincter muslces

what muscle of the iris causes it to dilate the pupil

dilator muslce

from top top to bottom label the structures of the iris

• sphincter muscles

• dilator muscles

name the structures of the iridocorneal angle

1. pars plana

2. ciliary body

3. par pilcata(ciliary process)

4. iris

5. sclera

label the structures of the lens

1. lens capsule

2. anterior lens epithelial cells

3. equitorial lens epithelial cells

4. equatorial fibers

5. anterior/posterior cortex

6. Nucleus

where do lens epithelial cells divide and from lens fibers

the equator

what happens to older lens fibers as newer ones are formed

they elongate and are moved internally

as more and more lens fibers made what happens to the central lens fibers

they become compressed and form a nucleus

as lens fibers grow anteriorly and posteriorly where do they meet

they meet at sutures

what do the anterior and posterior suture look like

anterior = y

posterior = upside down y

what lies between lens fibers and the lens capsule

the lens epithelium

what side of the lens capsule is the thickest

the anterior side

With no epithelium present after lens fibers elongate to a point there is no production of basement membrane to make it thicker this is why?

the posterior capsule is thinner

since the eye cannot grow and lens fibers are produced continuously what happens

the lens becomes more compact with age

the continual compaction of the lens can lead to what

nuclear sclerosis

what is cataracts

any opacity of the lens

if cataracts was the cause of opacity you’d see what in lens histology

morgagnian globules

what causes aphakia

loss of lens

what produces the aqueous humor of the anterior chamber

the ciliary body

what cells of the ciliary body produce the aqueous humor

the non pigmented epithelium

where does the aqueous membrane drain out of the eye

the iridocorneal angle

a patient with glaucoma most likely has a blockage of the what

iridocorneal angle

what part of the eye is involved in accommodation of the lens

the ciliary body

what is the difference between dog and cat iris melanin

dogs have darker and rounder granules than cats

what attaches the iris to the cornea

the pectinate ligaments

what is the makeup of the lens

• 65% water

• 35% crystalline protein

what are the stages of the vitreous humor

• primary

• secondary

• tertiary

what is the vitreous humor 99% made of

water

what is the function of the vitreous humor

to support the function of the retina and lens

what is the function of the choroid

provides support to the retina

the choroid supplies vessels to what portion of the retina

the outer portion

while the choroid has a tremendous amount of blood flowing through it, the blood is mostly used to do what

regulate heat

where is the tapetum most likely to be in the retina

the dorsal retina

what is the function of the tapetum

reflect light to increase vision in dim light

what lies directly over the tapetum

retinal pigmented epithelium

if RPE lies on the tapetum can it pigmented

no

a detachment took place in the retina and two layers came apart which of the layers was it most likely

the photoreceptors and retinal pigmented epithelium

what does the ganglion cell layer of the retina form

nerve fibers

what is the function of rods

• night vision

• motion

what is the function of cones

• day vision

• color

the axons from the ganglion cell layer are supported by what structure in the optic disk

lamina cribosa

in what animal is the optic disc non myelinated and difficult to see

cats

if the entire retina is vascularized that is known as what?

Holangiotic

if only the 3 aclock and 9 aclock positions are vascularized on the retina it is known as what?

merangiotic

if there is poor vasculature on the retina it is known as

paurangiotic

what animal is haloangiotic

cats and dogs

what animal is merangiotic

rabbits

what animal is paurangiotic

Horses

if an animal has no vasculature at its retina it is known as

anagiotic

what animals are anagiotic

birds