1. EYEBALL REVIEW QUESTIONS Ross University School of Veterinary Medicine Histology November 2003 Amy Fayette

2. What is the tear pathway?  Lacrimal puncta  Lacrimal canaliculi  Lacrimal sac  Nasolacrimal duct  Nasal cavity

4. What makes up the aqueous portion of tears?  Lacrimal gland  Gland of 3 rd eyelid

5. What type of tapetum lucidum does a dog have?  cellular

6. What are the corneal layers?  Anterior corneal epithelium  Subepithelial basement membrane  Stroma  Descemets membrane  Posterior corneal epithelium

7. What makes up the nervous tunic of the eye?  Retina –Optical part –Ciliary part –Iridal part

8. Where are tears drained?  Medial canthus via puncta

9. What makes up the vascular tunic of the eye?  Iris  Ciliary body and process  choroid

10. Where does the retina arrive from during development?  Neuroectoderm –diencephalon

11. What is the function and composition of the vitreous body?  99% water, some hyaluronic acid  Gel cortex, liquid center  Aids in maintaining shape and retinal apposition

12. What is the function of the tapetum lucidum?  Reflects light, providing additional stimulus to the photoreceptor cells in low light

13. What makes up the fibrous tunic of the eye?  Sclera and cornea

14. What type of tapetum lucidum does a cow have?  fibrous

15. What is the function of the iris?  Controls the amount of light admitted  Pigment and eye color

16. What produces the oily portion of tears? MMeibomian glands

17. Embryologically which parts of the eye are derived from the ectoderm?  Lens  Palpebral  Anterior corneal epithelium

18. What are the ten layers of the optical retina and what do they contain? PPigmented epithelium RRods and cones (process of photoreceptor cells) EExternal limiting membrane (cytoplasm of muller cells) EExternal nuclear layer (nuclei of photoreceptor cells) EExternal plexiform layer (axons and dendrites) IInternal nuclear layer (nuclei of bipolar cells) IInternal plexiform layer (axons and dendrites) GGanglion cell layer NNerve fiber layer (axons from ganglion cells) IInternal limiting membrane (cytoplasm of muller cells)

19. What are the two muscles associated with the iris and what is their innervation?  Sphincter pupillae m. = parasympathetic  Dilator pupillae m. = sympathetic

20. What are rods and what pigment do they utilize?  Low light sensitivity  Pigment = rhodopsin  Vitamin A important

21. What is the adnexa?  Palpebrae  Glands

22. What is meant by the “lens bow”?  The anterior lens epithelial cells elongate to form lens fibers

23. Embryologically which parts of the eye are derived from mesoderm?  Sclera  Choroid  Extraocular muscles  Ciliary muscles  Stroma

24. What is the conjunctiva?  Mucous membrane on innersurface of papebrae extending to the limbus of the cornea –Palpebral and bulbar conjunctivae  Stratified squamous epithelium  Goblet cells present in palpebral conjunctiva

25. What produces the mucous portion of tears?  Mucous glands

26. What is aqueous humor and what is a disease process associated with it?  Aqueous solution occupying the anterior and posterior chambers  Formed by ciliary epithelium  Nourishes cornea, maintains intraocular pressure and some ocular shape  Glaucoma

27. What are cones and what pigment do they utilize?  Visual acuity and color perception  Pigment = iodopsin

28. What does miosis and mydriasis mean? MMiosis = constriction MMydriasis = dilation

29. What attaches the lens to the ciliary body?  Zonule fibers

30. What are the two main functions of the coroid?  Contains nutrient blood supply to majority of retina  Contains tapetum lucidum

31. What is the drainage pathway of aqueous humor?  Posterior chamber  Pupil  Anterior chamber  Iridocorneal angle  Scleral venous plexus of systemic circulation