Ciliary body and Iris

Please double check the week :)

What are the 3 main function of the ciliary body?

Produces aqueous for the blood

Contains muscle to change lens curvature

Produce and maintain zonules of zinn

What is the ora serrata?

Junction between retina and ciliary body

What is the anterior surface of the ciliary body called?

Pars plicata

What is the posterior surface of the ciliary body called?

Pars plana

What are the key features of pars plana and pars plicata?

Pars plana is smooth and flat

Pars plicata is ridged

What forms the ciliary process?

Pars plicata surrounds iris, folded increase SA

How does the ciliary process happen?

Suspensory ligaments (fibres of zonules) release fibrillin protein

Attaches to pars plicata

What are the 3 parts of the ciliary body?

Ciliary epithelium

Ciliary stroma

Ciliary muscle

Good diagram that shows parts of the eye

What is the ciliary epithelium

2 cubical epithelium cells that cover ciliary body surface

What is the inner layer in the ciliary epithelium?

Non pigmented

On the outside

Anterior continuation of nervous part of retina

What is the outer layer in the ciliary epitheium?

Pigmented

Continuation of retinal pigment epithelium

What do the epithelium layers even do?

Both produce aqueous humor, act as filter

What is the ciliary stroma?

Bundles of loose connective tissue which is rich in blood vessels and melanocytes

What is the ciliary muscle?

Smooth muscle fibres forming bulk

What is the difference is strength between smooth and striated muscle?

Smooth is more elastic but more actin and myosin in striated so stronger

What happens when the ciliary muscle contracts?

Pulls ciliary body forward

Release tension in suspensory ligament

Increases refractive power

What is the thickness of the corneal epithelium?

50 microns thick, 5-6 cells

What cell types do corneal epithelium contain?

squamous, wing, basal

Where are the goblet cells?

Conjunctiva

What do goblet cells produce?

Mucus

To widen the palpebral fissure, the upper plate is pulled by which 2 muscles?

Levator aponeurosis

Muller’s muscle

What happens in parasympathetic and sympathetic stimulations to ciliary muscles?

Parasympathetic stimulation, muscles contract

Sympathetic stimulation, muscles relax

What is the iris?

Thin contractile pigmented diaphragm with pupil

Where is the iris?

Suspended aquous humour between cornea and lens

What is the ciliary margin / root of the iris?

Periphery of iris attached to anterior superior body

What is the pupillary ruff?

Dark pigmented ring to shield iris from excess light and stop scattering

What is the function of the iris?

Regulate the amount of light entering the eye

What is the size of the human iris?

12mm

What is the size of the human pupil?

1-8mm

What is heterochromia?

Two different eye colours

What determines the colour of the iris?

Pigment of melanocytes

What is the central pupillary zone?

Anterior eye of iris which controls size

What is Fuch’s cypt?

Benign cystic lesion in iris

What does a Fuch’s cyst look like?

Small clear and round blister

What causes Fuch’s cyst?

no clear cause, could be trauma or surgery

What is the treatment of Fuch’s cyst?

No treatment but can have laser therapy

Microscopically what 2 zones does the iris consist of?

Stroma and 2 epithelia layers

What is the stroma of the iris made of?

Vascular connective tissue

Collagen fibres, fibroblasts, melanocytes, nerve fibers and smooth muscle

What do sphincter pupillae muscles do?

Smooth muscle fibres that allows pupil to constrict

What are dilator pupillae muscles?

Thin myoepithelium cells that contract for pupil to dilate

What are the 2 main zones of the iris anterior surface?

Central pupillary zone and peripheral ciliary zone

Separated by collarette

What are contracted furrows?

Folds that form on posterior iris

Where are contracted furrows found?

Pupillary region close to margin

What can cause contracted furrows?

Folding of iris tissue as dilates and contracts due to change in light levels

What do contracted furrows do?

Help accommodate structural changes in iris as dilates or constricts

Reduces mehacnical stress

What are concentric furrows?

Circular ridges on the outer ciliary region

What do concentric furrows look like?

Circles giving iris patterned appearance near edge

What do concentric furrows do?

Provide flexibility to peripheral iris ensuring smooth movement during dilation and constriction