Lachrymal Apparatus and Protection of the Eye - PowerPoint Presentation

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Lachrymal Apparatus and Protection of the Eye

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JACKIE PETER

D11A012

ANIMALS PHYSIOLOGY 1 ( DVT 1033)UNIVERSITI MALAYSIA KELANTANFACULTY OF VETERINARY MEDICINE

Lacrimal

system

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General structure of

lacrimal

system.What is lacrimal system?

What are the components of

lacrimal apparatus? 3rd eyelid

Outline

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Different types of domestics animal eye

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General structure of

lacrimal

system

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Refers

to

tissues that make tears structure that

produce

and secrete tears and the structure that drain them away from the surface of the eye.

Lacrimal

System

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Lacrimal

Gland

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physiologic system containing the

orbital

structures for tear production and drainage.

structure that are responsible for:

ProductionDispersal

Disposal

Of tear.

Lacrimal

Apparatus

( apparatus

lacrimalis

)

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protective device

that helps keep the eye

moist and free of dust and other irritating particlesHelp keeping the eye lubricated and protected.

The tear produced by

lacrimal gland bring necessary nutrient.Lacrimal Apparatus

( apparatus

lacrimalis

)

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Lacrimal

glandGlands of the thirds eyelidLacrimal

canaliculi

Lacrimal sac Nasolacrimal duct

Components of

lacrimal

apparatus.

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3

rd

eyelid = Nictitating membrane

T- shaped piece of cartilage and smooth muscle set in medial canthus.Covered by conjuntiva.

Found in

domestics animals.

F (x) :

1. Provide addition

protection

underneath the

upper and lower eyelids.

2

. Consist

of

accesory

lacrimal

gland

which are also site of

production of tear.

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3

rd

eyelid in horse

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Eye Protection

Presented by: Lee Joy Yoong

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What protects the eyes ?

Eyelash Eyelid

Spectacle

Lacrimal / tear system ( NOT my part k ~)

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Eyelash (

es

)

P

rotect the eye from debris and perform some of the same function as whiskers do. A form of warning – closed reflectively when objects are beyond safe distance.

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Facts on eyelash.. So what ?

H

airs that grow at the edge of the eyelid.. . So who had it ?

Horse and cattle – featured prominently compared to other domesticated mammals (with the exception of dogs and cats due to varied breeds) .. Why ?

Camels – long and thick eyelash .. for what ?Inherited eyelash problems are common in some breeds of dogs .. What are the breeds ?Hornbills – prominent feather eyelashes, an uncommon feature in birds

Eyelash vipers – set of modified scales over the eyes which look much like eyelashes … but was it

e.l

. ?

Ostrich – vestigial feathers without barbs

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Madarosis

is the loss of eyelashes.

Blepharitis

is the irritation of the lid margin, where eyelashes join the eyelid. The eyelids are red and itching, the skin often becomes flaky, and the eyelashes may fall out.

Distichiasis

is the abnormal growth of lashes from certain areas of the eyelid.

Trichiasis

refers to ingrown eyelashes

.

Eyelash Nuisances

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Miscellaneous :

Mascara ?

Eyeliner ?Eye shadow ?

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Facts of eyelid

Thin fold of skin that covers and protects the eye… thinnest ?

K

eep the eyes from drying out when asleep .. How ?

Allows blinking.. For ?Opaque.. For what ?

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Complications in animal during dry / extreme / itch conditions

Subjects :

AardvarkPolar bear

Harbor

seal Nictating membrane – through evolution, a 3rd transparent / translucent eyelid

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In case where eyelid is not good enough… organism develops

SPECTACLE

Transparent membrane covering cornea… has 3 types :Fusion of upper eyelid and lower eyelid … so ?

From corneal skin (totally unattached, just covering )

From corneal skin (like b) but partly fused

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Tears

Presented by

Khirrol Nizam

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TEARS

lubricate the eye, and help to keep it clear of dust.

cornea is continually kept wet and nourished by basal tears.Tear fluid / Lacrimal fluid contains water, mucin, lipids, lysozyme

,

lactoferrin, lipocalin, lacritin, immunoglobulins, glucose, urea, sodium, and potassium.

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main functions of tears:

wetting the corneal epithelium, thereby preventing it from being damaged due to dryness.

creating a smooth optical surface on the front of the microscopically irregular corneal surface.acting as the main supplier of oxygen and other nutrients to the cornea.containing lysozyme

which destroys bacteria and prevents the growth of

microcysts on the cornea.flushing harmful bacteria and other microbes away from the eye.

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The lacrimal gland is the major producer of tears when one is crying or due to foreign body irritation.

Lacrimal

fluid, containing salts, proteins, and lysozyme, has several functions: taking the main nutrients (such as oxygen) to the cornea,carrying waste products away from the cornea,helping to prevent corneal infection, and maintaining the tonicity of the tear film.

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Three

very basic types of

tearsBasal tears - continually kept wet and nourished the corneaReflex tears - irritation of the eye by foreign particles, or from the presence of irritant substances such as onion vapors, tear gas, or pepper spray in the eye's environment

Psychic tears-

strong emotional stress, anger, suffering, mourning, or physical pain

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Precorneal

tear film — the thin layer of secretions from the

conjunctival goblet cells and lacrimal, tarsal and nictitans glands that covers the outer surface of the cornea and conjunctiva. (Saunders)

three layers:

lipid or oil layerlacrimal or aqueous layermucoid or mucin layer

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lipid or oil layer

Container – oils

Secretors – meibomian glands (or tarsal glands)Function – coats the aqueous layer; provides a hydrophobic barrier that evaporates and prevents tears from spilling onto the cheek.

Tear

fluid deposits between the eye proper and oil barriers of the lids.

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lacrimal

or aqueous layerContainer – water and other substances such as proteins (e.g., tear lipocalin, lactoferrin, lysozyme and lacritin

)

Secretors – lacrimal glandFunction – promotes spreading of the tear film; promotes the control of infectious agents; promotes osmotic regulation

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mucoid

or mucin layer Container – mucinSecretors – conjunctival goblet cells

Function –

coats the cornea;provides a hydrophilic layer;allows for even distribution of the tear film; covers the cornea

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Drainage of tear film

Lacrimal gland secrete lacrimal fluid flows surface of the eye gather lacrimal lake

puncta

lacrimal canaliculi lacrimal sac nasolacrimal duct nasal cavity

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Dry eye

A deficiency of any of the three layers of the tear

filmcausing anything from mild eye irritation to severe pain.Symptom excessive tearing or watering of the eyes eye irritation, scratchiness, grittiness, or pain; redness of the eye(s);

a burning sensation in the eye(s);

a feeling of something in the eye(s); eyes that feel “glued shut” after sleeping; blurred vision

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THANK YOU