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Lachrymal Apparatus and Protection of the Eye

Learn about the general structure and components of the lacrimal system, including the lacrimal gland, 3rd eyelid, and tear production. Discover how the eye is protected by eyelashes, eyelids, and the tear system. Explore different types of domestic animals and their eye structures. Presented by Jackie Peter in Animal Physiology at Universiti Malaysia Kelantan.

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Lachrymal Apparatus and Protection of the Eye

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  1. Lachrymal Apparatus and Protection of the Eye

  2. Lacrimal system JACKIE PETER D11A012 ANIMALS PHYSIOLOGY 1 ( DVT 1033) UNIVERSITI MALAYSIA KELANTAN FACULTY OF VETERINARY MEDICINE

  3. Outline • General structure of lacrimal system. • What is lacrimal system? • What are the components of lacrimal apparatus? • 3rd eyelid

  4. Different types of domestics animal eye

  5. General structure of lacrimal system

  6. Lacrimal System • 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.

  7. Lacrimal Gland

  8. Lacrimal Apparatus( apparatus lacrimalis) • physiologic system containing the orbital structures for tear production and drainage. • structure that are responsible for: • Production • Dispersal • Disposal Of tear.

  9. Lacrimal Apparatus( apparatus lacrimalis) • protective device that helps keep the eye moist and free of dust and other irritating particles • Help keeping the eye lubricated and protected. • The tear produced by lacrimal gland bring necessary nutrient.

  10. Components of lacrimal apparatus. • Lacrimal gland • Glands of the thirds eyelid • Lacrimalcanaliculi • Lacrimal sac • Nasolacrimal duct

  11. 3rd 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 ofaccesorylacrimal gland which are also site of production of tear.

  12. 3rd eyelid in horse

  13. Eye Protection Presented by: Lee Joy Yoong

  14. What protects the eyes ? • Eyelash • Eyelid • Spectacle • Lacrimal / tear system ( NOT my part k ~)

  15. Eyelash (es) Protect the eye from debris and perform some of the same function as whiskersdo. A form of warning – closed reflectively when objects are beyond safe distance.

  16. Facts on eyelash.. So what ? Hairs 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

  17. Eyelash Nuisances • 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.

  18. Miscellaneous : Mascara ? Eyeliner ? Eye shadow ?

  19. Facts of eyelid Thin fold of skin that covers and protects the eye… thinnest ? Keep the eyes from drying out when asleep .. How ? Allows blinking.. For ? Opaque.. For what ?

  20. Complications in animal during dry / extreme / itch conditions Subjects : Aardvark Polar bear Harbor seal Nictating membrane – through evolution, a 3rdtransparent / translucent eyelid

  21. 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

  22. TearsPresented by KhirrolNizam

  23. 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.

  24. 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 lysozymewhich destroys bacteria and prevents the growth of microcysts on the cornea. • flushing harmful bacteria and other microbes away from the eye.

  25. 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.

  26. Three very basic types of tears • Basal tears - continually kept wet and nourished the cornea • Reflex 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

  27. 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 layer • lacrimal or aqueous layer • mucoid or mucin layer

  28. 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.

  29. lacrimalor aqueous layer • Container – water and other substances such as proteins (e.g., tear lipocalin, lactoferrin, lysozyme and lacritin) • Secretors – lacrimal gland • Function – promotes spreading of the tear film; promotes the control of infectious agents; promotes osmotic regulation

  30. mucoidor mucin layer • Container – mucin • Secretors – conjunctival goblet cells • Function – coats the cornea;provides a hydrophilic layer;allows for even distribution of the tear film; covers the cornea

  31. Drainage of tear film Lacrimalgland secretelacrimal fluid flows surface of the eye gatherlacrimal lake punctalacrimalcanaliculilacrimal sac nasolacrimal duct nasal cavity

  32. Dry eye • A deficiency of any of the three layers of the tear film • causing 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

  33. THANK YOU

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