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Ciliary Body, etc

Ciliary Body, Crystalline Lens, Iris

What are the two main functions of the ciliary body? 1) secrete aqueous humor; 2) control accommodation of crystalline lens
How wide is the ciliary body? approximately 6 mm wide
The ciliary body extends from the _________ to the ___________. ora serata to the scleral spur
What is the outermost layer of the ciliary body? Supraciliaris
What other name is the supraciliaris known as? supraciliary lamina
Which part of the ciliary body is adjacent to the sclera? supraciliaris
What is the supraciliaris made up of? Loose, connective tissue arranged in ribbon-like layers
What three things does the supraciliaris contain? pigmented melanocytes; fibroblasts; collagen bands
Why are the collagen bands in the supraciliaris important? they allow the ciliary body to slide against the sclera without breaking
What is the flatter region of the ciliary body that extends from the posterior of the pars plicata to the ora serata? Pars Plana
Which part of the ciliary body contains the ciliary processes? The pars plicata
How many ciliary processes are in the ciliary body? 70 to 80
What is the length of the ciliary processes? 2 mm
What are the regions between the ciliary processes called? valleys
The zonule fibers attach to the pars plana or the pars plicata? Both
The pigmented epithelium of the ciliary body is continuous with? Iris epithelium and the retinal pigmented epithelium
The non-pigmented epithelium is composed of what type of cells in the pars plana? Columnar
The non-pigmented epithelium is composed of what type of cells in the pars plicata? Squamous
Posteriorly the non-pigmented epithelium becomes...? retinal nervous tissue
Which epithelial cells are active and secrete aqueous? The non-pigmented epithelial cells
What type of tissue is the ciliary muscle made up of? Involuntary, smooth muscle tissue
The ciliary muscle is used for...? focusing at near
When the ciliary muscle contracts the lens gets a _______ front and back surface. steeper
When the muscle contracts it takes the tension off of the ____________, allowing the lens to get rounder for ____________. zonule fibers; accommodation
What are the three types of muscle fibers in the ciliary muscle? Longitudinal; Radial; Annular
Which muscle type lies adjacent to the supraciliaris? Longitudinal
Which muscle type is the middle transition? Radial
What is the innermost region of the ciliary muscle? Annular tissue
The ciliary stroma is highly vascularized, true or false? true
What type of tissue is the ciliary stroma made of? Loose, connective tissue
The ciliary stroma lies between which layers of the ciliary body? Between the muscle and epithelial layers
What forms the core of each of the ciliary processes? The ciliary stroma
Is the crystalline lens vascular? No, it is avascular.
What is the location of the crystalline lens? In the posterior chamber, anterior to the vitreous chamber.
Is the crystalline lens biconvex or biconcave? biconvex
What is the thickness of the unaccommodated lens? 3.5-5 mm
What is the diameter of the lens at infancy? 6.5 mm
What does the diameter of the lens reach during the teenage years, and then doesn't change much? 9.0 mm
How much does the thickness of the lens increase each year? .02 mm
What is the power of the unaccommodated lens? 20 diopters
What the eye accommodates it __________ the power of the lens. increases
At what age do we have the max accommodative amplitude? Ages 8-12
What is the max acommodative amplitue? 14 diopters
At what age do you have zero accommodative power 50
What is the lens capsule? A transparent envelope that surrounds the entire lens
What is the lens capsule classified as? A basement membrane
What is the capsule primarily made of? collagen
The anterior capsule ________ with age. Thickens
What is the anterior capsule secreted by? anterior lens epithelium
The anterior lens capsule is how thick? 1 mm
Does the anterior lens epithelium produce new cells? Yes
The new cells in the anterior lens epithelium form the _______, when they elongate and the nuclei move with the cytoplasm. lens bow
Old cells go towards the ________________? embryonic nucleus
What are the primary lens fibers that form the very center of the crystalline lens? Embryonic nucleus
When are the fetal nucleus fibers laid down? Before birth
Which fibers are formed between birth and sexual maturation? Adult Nucleus
When is the lens cortex formed? After sexual maturity
Do cells in the lens get larger as the get older? No, they shrink
What else happens to cells in the lens as they get older? loose their nuclei; migrate towards the center; become compressed
What happens to the nucleus of the lens as it ages? It becomes larger and less transparent
How much bigger is the lens at age 65, than at age 20? 1/3 larger
What is the primary function of the lens? Refracting light
In the center of the lens (light path) there are many or few cells? Very few cells
What does the lens contain that allows it to be transparent? An orderly arrangement of collagen fibers
What is the index of refraction of the lens? 1.42
The crystalline lens transmits light including which wavelengths? 400 to 1000 nm
The cornea absorbs wavelengths below ___nm? 300
The lens absorbs wavelengths between ___ and __nm? 300 and 400
Light greater than ___ nm will transmit to the retina. 400
Any opacity of the crystalline lens is technically considered a ________? cataract
What is the most common type of cataract? Age related/senile
What are age related/senile cataracts linked to? Long-term exposure of UV rays
What kind of cataracts are linked to German measles (rubella) in the mother during pregnancy? Congenital
What can cause traumatic cataracts beside trauma to the eye? Exposure to certain gasses
What is an opacity located in the embryonic or fetal nucleus? Nuclear cataract
What is the most common type of nuclear cataract, characterized by a yellowing of the lens. Senile Nuclear Sclerosis
Which type of cataract is an opacity located in the cortex? Cortical
A cortical cataract is only problematic when...? It spreads to the central vision
Where is a posterior subcapsular cataract located? on the backside of the crystalline lens
What causes a posterior subcapsular cataract to form? irregular migration of the epithelial cells
What has been linked to posterior subcapsular cataracts? Long-term use of steroids
What type of cataract develops from elevated glucose levels and is characterized by decreased transparency. Diabetic cataracts
What type of anesthetic is used for cataract surgery? Local anesthesia
What type of incision is required for cataract surgery? A small incision into the anterior chamber
What is opened during cataract surgery? The anterior lens capsule
What is removed, and what is left intact during cataract surgery? The epithelium and all lens fibers are removed, leaving only the capsule intact.
What is an IOL? intra-ocular lens
What is the main function of the iris? To regulate the light let in through the pupil
What divides the anterior chamber from the posterior chamber? Iris
Where is the center of the pupil located in relation to the center of the iris? Slightly medial (nasal) and inferiorly
The pupil can vary from _ to _ mm, depending on illumination. 1 to 9 mm
The pupil is myotic (smaller) in what conditions? brightly lit conditions
The pupil is mydriatic (bigger) in what conditions? dimly lit conditions
What is the diameter of the iris? 12 mm
Which epithelium lies nearest to the stroma in the iris? Anterior epithelium
What is the anterior epithelium of the iris made uop of? myoepithelial cells
The anterior epithelium is the only structure in the body that contains myoepithelial cells, true or false? True
Which epithelium in the iris is heavily pigmented? Posterior epithelium
What is the pupillary ruff (frill)? When the epithelial cells curls around from the posterior iris to the anterior iris.
What does the pupillary frill encircle? pupil
What color is the pupillary frill? copper
The pupillary frill has a ________ appearance. serrated
What is the collarette? A circular ridge 1.5mm from the pupillary margin, that separates the iris into the ciliary and pupillary zones.
What is the outer edge periphery of the iris? The iris root
How thick is the iris root? .5 mm
What is the thinnest part of the iris? iris root
The iris root joins the iris to the...? ciliary body
What is iridodialysis? a blunt trauma to the eye, where the root of the iris tears away from the ciliary body
What complications are caused from iridodialysis? hemorrhaging and paralysis of the muscles in the eye
What does the stroma in the iris contain? fibers and blood vessels and melanocytes which contain melanin
Where is the sphincter muscle located? within the pupillary zone of the stroma
What type of cells is the sphincter muscle made up of? smooth muscle cells
How wide is the sphincter muscle? .75 to 1 mm
Contraction of the sphincter muscle causes...? the pupil to constrict (myosis)
The sphincter muscle is innervated (activated) by the...? parasympathetic nervous system
The parasympathetic nervous system is part of the _________ system, which means you don't have to think about it. autonomic
Sympathetic nervous system, example dilation of the pupil, causes... speeding up
The parasympathetic nervous system, example constriction of pupils, causes... slowing down
The contraction of the dilator muscle...? pulls the pupillary portion of the iris towards the root, enlarging the pupil
What is the contraction of the dilator muscle known as? Mydriasis
Dilation is a ___________ muscle? sympathetic
What are holes in the front of the iris that allow aqueous quick exit and entrance to the stroma of the iris. crypts
What factor decide iris color? The arrangement and density of connective tissue in the anterior border and stroma, and the amount of pigment.
If the iris is heavily pigmented, the anterior of the iris will appear...? brown and smooth
Lighter irises will appear...? Blue, grey, or green
What causes albinos to have red eyes? There is no pigment in the epithelial layer
What is an area of hyper-pigmentation on someone's iris? Nevus
What is it called when someone has two different colored irises, or if a portion of one's iris is different from the rest. heterochromia
What is an iris synechiae? An abnormal attachment of the iris surface to another surface.
What is an iridectomy? A wedge-shaped, full thickness section of the iris is removed for aqueous flow.
What is an iridotomy? Hole going through the iris to allow aqueous flow, performed by a laser.
Which is less invasive, an iridectomy or iridotomy? iridotomy
Created by: griffiskr