Tear film Flashcards
The tears are a mixture of secretions from the _ and _
Main Lacrimal gland, accessory lacrimal gland and goblet cells & meibomion glands
The tears film contains a high concentration of
Proteins
The tear film is made up of _, _ and _
Albumin, lysozyme, and ganna globulin
The average ph of the tears _
7.4
The the three layers of the tear film are the _ layer, the _ layer and the _ layer
Superficial lipid, middle aqueous, mucin
The superficial lipid (oil) layer of the tear film is from the secretions of the _ and _
Meibumian glands, glands of Zeis
The _ prevents evaporation of the aqueous layer of the tear film
Lipid layer
The middle aqueous layer of the tear film is secreted by the _ and _
Main lacrimal and accessory lacrimal
The _ layer of tear film contains lysozyme that is an antibacterial agent and antibodies ( predominantly immunoglobulin igA) that assist in bacterial invasion
Aqueous
The mucin layer of the tear film is secreted by the _ in the conjunctiva
Goblet cells
The _ of the tear film is partially absorbed by the corneal epithelium providing a hydrophilic ( water attracting) surface for the aqueous tears to spread on
Mucin layer
Dry eyes are medically termed as
Keratoconjunctnitis sicca
The_ secrete enough tears to keep the cornea wet under most circumstances and the _ secretes enough you help cover stressful circumstances such as drying from exposure to hot air, corneal injuries, foreign bodies and emotional upsets
Main & accessory lacrimal glands , main lacrimal gland
Two tests for measuring tear function are
Schirmer and tear break up time - TBUT
Aqueous deficiency is the most common tear film problem and is treated with
Artificial tear
The _ is a thin transparent mucous membranes lining the inner surface of the eyelids and the globe
Conjunctiva
The conjunctiva
Helps protect the eye from bacteria and produces the mucus layer of the tear film
The _ form a transitional area between the bulbar and palpebral conjunctiva
Superior & inferior fornices
The part of the conjunctiva that lines the inner lids is the _ conjunctiva
Palpebral
The part that covers the the globe is called the _ conjunctiva
Bulbar
The conjunctiva is composed of two layers , _ layer and the ___ layer
Epithelium, adenoid and fibrous
The goblet cells that secrete mucus into the tear film are in the _ layer of the conjunctiva
Epithelium
The _ deep layer is composed of blood vessels, nerves, glands, and compacted connective tissues containing Mueller’s muscle
Fibrous
The accessory lacrimal glands are located in the _-
Fibrous layer of the conjunctiva
The blood supply of the _ conjunctiva comes from the peripheral and marginal arterial arcades of the eyelid
Palpebral
The blood supply of the _ conjunctiva comes from the only the peripheral arterial arcade and extends within 4mm of the limbus and anterior ciliary Arties
Bulbar
The anterior ciliary arteries from superficial conjunctival and deep episcleral _ ( network of vessel) at the limbus that when inflamed is known as the ciliary flush
Pericorneal
The bulbar conjunctival vessels are dilated in inflammations of the
Bulbar conjunctiva
The superficial conjunctival peri-corneal plexus is infected in inflammation of the
Cornea
The deep episcleral peri-corneal plexus is injected in inflammations of the
Iris and Ciliary body and in angle closure glaucoma
The conjunctiva is innervated by the 1st and 2nd division of the_ cranial nerve
5th, trigeminal
The _ is transparent avascular tissue that functions as a refracting and protective membrane
Cornea
The corneal refractive power is equivalent to a _ diopter lens, which is about _ of the total refracting power of the eye ( 60 diopter)
+43 , 70%
The average adult cornea is _ thick at the periphery __ thick in the center and __ in diameter
1mm, 0.5 to 0.6 , 11.5
The corneal growth in humans is complete at about _
6 years of age
The layers of the cornea from anterior to posterior are
Epithelium, bowmans layer, stroma, dua’s layers, descemets membrane, endothelium
The _ regenerates when damaged and restricts passage of fluid to maintain transparency
Epithelium
The cornea is innervated by the __ specifically the nasocililary branch that enters the stroma and branch to the epithelium
1st division of the trigeminal nerve
_ is collagen zone not containing cells that is a barrier to microorganisms and does not regenerate if damaged, leaving scar
Bowman’s layers
The _ makes up 90% of the total corneal thickness
Stroma
The stroma is made up of __ in bundles arranged in a lamellar pattern parallel to the corneal surface, maintaining corneal transparency
Collagen fibrals
The new layer of cornea was recently discovered called the _ . It is between the stroma and descemet’s membrane
Dua’s layers
__ is a true basement membrane secreted by the underlying endothelium that is tough and resistant to penetration and can get folds in it during hypotony
Descemet’s membrane
The _ is a single layer of hexagonal cells that get its oxygen from the aqueous and pumps waste and fluid from the stroma, keeping the cornea in a normal dehydrated state. The cells do not regenerate.
Endothelium
