Iris and Ciliary Body

development of apical to apical NE and PE

due to folding of the optic cup

posterior pigmented epithelium

epithelial cells, larger and more pigmented than anterior pig. epith. basal side faces posterior chamber

radial portion of ciliary muscle

inserts at base of ciliary processes (pars plana) transition layer btwn longitud and circular

circular portion of ciliary muscle

inserts at ciliary body btwen pars plana/plicata (pars plicata)

longitudinal portion of ciliary muscle

inserts into anterior choroid

iris location w/in segments of eye

iris divides anterior and posterior chamber of anterior segment

albinism affect on iris

iris isn't pigmented - lets more light into eye (makes VA worse)

locations of muscles in iris layers

iris sphincter = stroma, in circle at tip of iris iris dilator = stroma and anterior pigmented epith, runs entire lengths of iris PUPIL CONSTRICTION/DILATION

supraciliaris features

melanocytes, fibroblasts, collagen,

anterior non-pigmented epithelia

on posterior side of iris, made of myoepithelial cells (epith cells + muscle cells from iris dilater)

affect of accommodation on other eye structures

opens trabec meshwork, drains aqueous better

melanocytes in anterior border layer/stroma/anter, posterior epith.

present in all layers most in anterior border layer (gives iris its color)

regions of iris

pupillary zone (close to pupil) collarette ciliary zone (close to cil body)

wrinkles in iris

radial and circular types - do due the iris contracting/expanding (creates "slack" in the iris) (on anterior and posterior parts of iris)

iris dilator

radial muscle, goes from anterior pigmented epith into stroma, SYMPATHETICALLY INNERV., extends entire length of iris

clump cells

scavenger cells in iris stroma that eat pigment moleclules

orgin of ALL portions of ciliary muscle (circular, radial, longitud)

sceleral spur

irides

term for many iris's

ciliary body functions

accomm, makes aqueous (and some vitreous) humor

pigmented cells of iris

all contribute to iris color, but ant. border layer most imporant ant. border layer ant/post. pigmented epith.

layers of iris

anterior border layer (anterior side) stroma/iris sphincter muscle (middle) anterior/posterior pigmented epith./iris dilater muscle (posterior side)

blood supply of choroid

anterior choroid: MACI posterior choroid: short posterior cil. artery)

anterior border layer of iris

anterior part of iris STROMA, has meshwork of fibroblasts and melanocytes with melanin (give eye its color) NOT EPITHELIUM!

linking between cells in anterior/posterior pigmented epith.

apical ends of each layer face each other cells joined laterally by tight junctions/desmosomes

thickest anterior border layer

at collarette (where whole iris is thickest)

ciliary body location

behind iris, in front of lens (forms posterior chamber) continuous with choroid posteriorly continuous with iris anteriorly

ciliary stroma

between muscle layer (outer) and epithelial layer (inner) contains MACI, collagen, ciliary processes

pupillary ruff

border between pupil and iris formed by posterior pigmented epithelial that wraps around to anterior side of iris (ant. border layer)

crenations

bumps in the pupillary ruff

venous drainage of iris/CB

chorodal veins, then vortex veins

ciliary body location

choroid becomes ciliary body sclera is on top of both choroid and ciliary body

continuity of cil body/choroid

cil body supraciliaries = contin w/surprachoroidal space cil body stroma = contin w/choroid stroma cil body pigmented epith = continous w/choroid RPE

iris sphincter contraction

circular fibers close like camera, cause more visible pupillary ruff to be seen

iris sphincter

circular muscle, in stroma, PARASYMP. innervated (short cil. nerves) constricts to light and accommodation

ciliary body shape

circular viewed from front triangle viewed from side

trabeculae

collagen fibrils in stroma, seen as radial fibers

MACI flow w/in iris/CB

CB: in stroma, ciliary processes iris: stroma, anterior iris

blood supply of iris/CB

MACI (from long post. cil. artery and anterior ciliary arter) has pericytes to prevent damage from pupil contraction

iris color

darker color due to higher concentration of melanin pigment in melanocytes (most people have same # of melanocytes - so conc. of melanin determines color)

heterochromia

different colored eyes due to asymmetric development or injury

Collarette

divides iris into pupillary zone and ciliary zone

zonules

fibers that attach to lens, come from pars plana AND the ciliary processes of pars plicata

pars plicata

folded part of CB where ciliary processes jutt out ciliary processes are where zonules start ciliary processes/zonules get smaller with age

Major arterior circle of the iris (MACI)

formed by ant. ciliary and long posterior ciliary arteries inside CB stroma (supplies iris and anterior choroid as well)

layers of ciliary body

from anterior to posterior Supraciliaris Ciliary Muscle (longitudinal, radial, circular) Stroma Epithelium (pigmented, then nonpigmented)

type of crypts

fuchs crypts = large, in pupilary zone ciliary crypts = small, in ciliary zone

iris nevus

harmless accumulations of melanocytes in anterior border layer of iris

pars plana

has ciliary bays which go to ora serata (posterior) has striae ciliaris which goes to pars plicata and becomes zonules

pupil

hole in iris, changes in response to light decreases aberrations, increases depth of focus

crypts

holes between the trabeculae strands

continuity of iris/cil body

iris stroma = contin. w/cil body stroma iris anterior pigmented epith = contin. w/outer pigmented epith (PE)of cil body iris posterior pigmented epith (DARK stain) = contin. w/inner non-pigmented epith. (NE) of cil body

uveal tunic of eye

iris, cil body, choroid (all vascular) iris is most anterior part of uveal tunic

eye color of babies

lighter eyes at first, then darker as melanocytes develop

sensory nerves of iris/CB

long ciliary nerves

features of light colored eyes

lower concentration of pigment (melanin) often blue due to light scatter/absorption of shorter wavelengths

ciliary muscle

muscle in the ciliary body that controls accomm

ciliary muscle

muscle that contracts, releasing tension on zonules, allow lens to become rounder (ACCOMODATION) has circular, radial, and longitudinal portions

pupil location

nasal/inferior part of iris

minor arterial circle of iris

near collarette, supplies pupillary iris region, has tight junctions (not complete circle like MACI)

source of ciliary body epithelium

neural ectoderm (like retina)

nonpigmented ciliary epithelium

next to aqueous humor, source of some zonules (the ones coming from pars plana) tight junctions help form blood aqeous barrier

pigmented ciliary epithelium

next to stroma, lots of melanocytes (pigments) lots of gap junctions laterally

ciliary body epithelium

outer pigmented epithelium inner nonpigmented epithelium apical ends of each layer face each other (just like iris epithelia) lots of gap junctions between the two

parasymp/symp of iris/CB

parasymp: ciliary ganglion to short ciliary nerves (stim. ciliary muscle, iris sphincter, choroidal vessels) symp: cervical ganglion to long ciliary nerves (relexes cil muscle, iris dilator, blood vessels)

parts of ciliary body

pars plana = flat part pars plicata = folded part

limbus description

the iris only covers the space behind the cornea, is below/above the sclera

iris thickness

thick at collarette thin at root (peripheral part)

supraciliaris

transition zone between sclera and ciliary body continuous with surprachoroidal space (choroid) - both are under lamina fusca (sclera)

valleys of kuhnt

valleys in between pars plicata mountains

iris stroma

vascular, has collagen, GAGS pigmented cells (melanocytes) and nonpigmented cells (fibroblasts, normal tissue cells)

orra serrata

where dentate processes (teeth like) of retina meets ciliary bays of pars plana

iris root

where iris attaches to CB, seen as the limbus