1. Anatomy of the eye & ear

2. THE EYE

3. ANATOMY OF THE EYE Sophisticated systems that includes the work of:
Retina receptors
Pupil dilation and contraction
6 oculomotor muscles
12 cranial nerves

4. EXTERNAL EYE Only about 17% of the eye is visible
About 2.5 cm in diameter
Accessories / external features of the eye:
Palpebrae - eyelids; evenly distribute tears across the surface of the eye to keep it moist
Eyelashes
Palpebral fissure – cleft between upper/lower eyelid
Lacrimal caruncle – contains sebaceous/sweat glands
Lateral / medial canthus – 2 points where the upper/lower eyelid meet
Conjunctiva – thin mucous membrane that covers the eye / lubricates eye and contains vessels

5. Eye Glands / Ducts
Ciliary glands – modified sweat glands to lubricate the eyeball
Tarsal glands – secrete an oily lubricant to prevent eyelids from sticking together
Lacrimal glands – contains 12 excretory larcrimal ducts that secrete tears and lacrimal fluid
Lacrimal Apparatus
Lacrimal fluid contains lysozyme  fluid moves across eyeball surface and enters two openings in medial canthus  superior / inferior lacrimal puncta  lacrimal canals  lacrimal sac  nasolacrimal tract drains the tears into the nasal cavity

6. Eye Muscles – come back to haunt us

7. INTERNAL EYE Fibrous tunic – dense connective outer layer tissue
Sclera – white part of the tunic that covers the eye
Corneal lambus – the border between sclera and cornea; contain canal of Schlemm,
Cornea – NOT covered by sclera, transparent tissue where light enters the eye
Vascular tunic (uvea)
Iris (anterior)
Lens (posterior to iris) – focuses light
Ciliary body – where iris attaches
Pupil
Choroid (posterior) – melanin that absorbs light and prevents against reflection
Neural tunic (aka retina)
Pigemented part (outer layer)
Neural part – contains light-sensitive photoreceptors
Aqueous humor – maintains intraocular eyepressue and supplies nutritents to lens/ cornea
Vitreous body – holds retina against choroid and prevents collapse

9. How does the pupil change size?
Pupillary sphincter muscles / pupillary dilator muscles
Parasympathetic vs Sympathetic innervation

10. Cellular Organization of the Retina
Neural part of the retina contains the photoreceptors
And 2 types of sensory neurons  bipolar cells and ganglion cells
Photoreceptors
Rods – motion detection
Cones – visual acuity
Light  pigemented area  neural part  photoreceptors  bipolar cells  ganglion cells axons converge at optic disc
Amacrine cells – communication between bipolar and ganglion cells
Horizontal cells – inhibit or facilitate communication b/w photoreceptors and bipolar cells
Macula lutea – contains many cones
Fovea (center of ML) – sharpest vision at this point / no rods here

11. Diseases of the Eye Glaucoma Diabetic Retinopathy Conjunctivitis
Macular Degeneration
Sty

12. Marijuana and Glaucoma
THC causes the blood vessels in the eye to decrease
Therefore, reduced IOP levels

13. THE EAR

14. Anatomy of the Ear External – direct sound waves
Middle – direct sound waves
Outer – balance and hearing

16. External Ear
Pinna, auricle – funnels sound waves into external acoustic meatus  tympanic membrane (eardrum)
Ceruminous glands – prevent dust and debris from entering the middle ear

17. Middle Ear AKA tympanic cavity
Connected to the back of the upper throat by the auditory tube
Sound vibrations  malleus  incus and stapes  pushes on the oval window (inner ear)  stimulate auditory receptors
Tiny muscles – tensor typani and stapedius
Smallest skeletal muscles on the human body

18. Inner Ear – Regions Cochlea – receptors for hearing
Vestibule – receptive to static equilibrium
Semicircular canals – receptors for “dynamic equilibrium” (when body moves)
Contain semicircular ducts that have a swollen ampulla that houses the balance receptors called cristae

19. Inner Ear – Regions Vestibule Contain utricle and saccule
Maintain maculae
Receptors that maintain static EQ
Suspended in a gel matrix which also contains statoconia (calcium carbonate crystals)

20. Inner Ear – Regions Cochlea
3 ducts in a spiral formation – chochlear duct
Contains hair cells that are sensitive to vibrations
Contains sensory receptor, organ of Corti
Inner hair cells / outter hair cells
Vestibular duct and tympanic duct - filled with perilymph
Basilar membrane – where hair cells occur