1. Special Senses Week 12

2. Exterior Eye Anatomy 1?2? 3?

3. Conjunctiva Cornea Sclera Orbicularis oculi muscle (Under eyebrow) Transparent mucus membrane Covers only the white of the eye -Produces mucus which prevents the eyes from drying out

4. Exterior Eye Anatomy (palpabrae) Sebaceous and sweat gland

5. Exterior Eye Anatomy Pin holes Tears are a dilute saline solution that cleans and protects, moistens and lubricates the eye If you have a cold, the nasal mucosa becomes inflamed. No tear drainage into nose. Watery eyes

6. Extrinsic Eye Muscles Extrinsic Eye Muscles A.Lateral rectus (abducens) B.Inferior rectus C.Superior rectus D.Inferior oblique: up and lateral E.Superior oblique: down and lateral (trochlear) F.Levator palpebrae superioris G.Medial rectus (not shown)

7. Objective 1:Structures of the Human Eye Pushing the Limits: Sight, video 3

8. Internal Eye Three concentric tunics (layers) of the eye: Outer fibrous tunic Outer fibrous tunic Middle vascular tunic Middle vascular tunic Inner sensory tunic Inner sensory tunic

9. Internal Eye Three concentric tunics (layers) of the eye: Outer fibrous tunic Outer fibrous tunic– sclera, cornea Middle vascular tunic Middle vascular tunic Inner sensory tunic Inner sensory tunic Cornea Sclera Lens (white of the eye) Protects the eye Attaches eye muscles Window Lets light enter eye No blood vessels Can be transplanted easily

10. Internal Eye Choroid Iris Pupil Suspensory ligaments Lens Ciliary process Ciliary muscle Ciliary Body Three concentric tunics (layers) of the eye: Outer fibrous tunic Outer fibrous tunic Middle vascular tunic Middle vascular tunic– choroid, ciliary body (ciliary muscle & process), iris Inner sensory tunic Inner sensory tunic Sclera Cornea Blood vessel rich, dark brown membrane Controls lens shape Makes aqueous humor Allows light to enter eye Modulates pupil size

11. Pupil dilation & constriction

12. Internal Eye Retina Optic Nerve (CN II) Three concentric tunics (layers) of the eye: Outer fibrous tunic-connective tissue Outer fibrous tunic-connective tissue Middle vascular tunic Middle vascular tunic Inner sensory tunic Inner sensory tunic- retina Choroid Sclera

13. Light Absorb light and prevent it from scattering

14. Retina Rods: Night vision Peripheral vision Cones: Visual acuity (sharpness) Color vision

15. Retinal ganglion cells Human Retina Bipolar cell nuclei Pigmented epithelial layer Nuclei of rods & cones Outer segments of rods & cones Rods & Cones Vascular Tunic

16. Posterior Wall (fundus) of the Eye Macula lutea Fovea centralis Optic disk (blind spot) Optic nerve Retina (no rods and cones) (all cones)

17. OPTIC DISC The OPTIC DISC is the region were: the optic nerve exits the eye The central artery and vein of the retina enter and exit the eye There are no photoreceptors, the “blind spot”

18. Ophthalmoscope View

19. Fovea centralis & Macula lutea greatest cone density The macula lutea is an oval region lateral to the optic disc, at it’s center lies the fovea centralis, the area of greatest cone density in the retina.

20. Segments of the Eye Anterior segment aqueous humor Anterior segment: area in front of the lens, filled with aqueous humor Posterior segment vitreous humor Posterior segment: area behind the lens, filled with vitreous humor Vitreous humor (made once for life) (Constantly generated and removed)

21. Anterior Segment Anterior chamber Anterior chamber: between the cornea and iris Posterior chamber Posterior chamber: between iris and lens Suspensory ligaments Scleral venous sinus (Canal of Schlemm) Aqueous humor made by capillaries in ciliary process Drops into posterior chamber Passes to anterior chamber

22. Objective 4:Ear Anatomy

23. 123 (the rim)

24. External Auditory Meatus

25. Middle ear: air filled (links with nose!)

26. Inner ear Cochlear nerve Vestibular & Cochlear nerves join to become the Vestibulocochlear Nerve (CN VIII)

27. Cochlea Identify given structures from models and slides S.V. S.T.

28. Stapes Cochlea

29. Cochlea, cs (Perilymph) (Endoymph)

30. Cochlea histology

31. Cochlea Endolymph Perilymph = CSF Endolymph = intracellular fluid

32. Hearing physiology

34. Vibrations Medulla Midbrain Primary auditory cortex in temporal lobe Vestibulocochlear Nerve (VIII)

35. Balance & Equilibrium

36. Inner Ear

37. Vestibule – utricle & saccule Static equilibrium Responds to changes in linear movement (vertical & horizontal) Monitor head position, posture

38. Semicircular Canals - ampulla Dynamic equilibrium Responds to changes in rotational movement Balance

39. Objective 2:Cow Eye Dissection

40. lens retina Identify all external and internal structures listed! Follow the directions given in the Lab Manual!

41. Tapetum lucidum Iridescent portion (retina removed) Not present in humans

42. Objectives 3 & 5: Experiments

43. On the Practical: Identify the macro-structures of the eye from models and the cow eye Identify the macro-structures of the ear from models Identify the microscopic structures of the retina and cochlea Lab Activity: Dissect cow’s eye Perform visual, auditory & balance experiments and analyze