Specialized Senses

Smell Olfaction Olfactory epithelium: receptors, supporting cells, stem cells Olfactory glands secrete mucous to cover epithelium ~10-20 million receptors in ~5 square cm Olfactory bulb

Taste Gustation (taste buds) Tongue, pharynx, larynx Papillae (epithelial projections) Circumvallate papillae- most dense region of taste buds Gustatory cells/taste hairs Sweet, salty, sour, bitter, umami

Vision Palpebrae: windshield wipers for the eye Lacrimal caruncle: eye boogers Sty: sebaceous gland infection Conjuctiva: mucous membrane of the eye Conjuctivitis Lacrimal gland (tears)

Extrinsic Muscles of the Eye Inferior rectus Medial rectus Superior rectus Lateral rectus Inferior oblique Superior oblique

The Eye Fibrous tunic: outermost layer of eye Sclera (blood flow/muscle attachment) and cornea Mechanical support/physical protection, attachment for muscles, focusing Vascular tunic: Iris (blood vessels, pigments, instrinsic muscles), ciliary body, choroid

The Eye Neural tunic (retina) Pigmented part Absorbs light Neural part Photoreceptors, supporting cells/neurons, blood vessels

The Retina Rods: light sensitive Cones: color sensitive Macula Lutea (“yellow spot”) Highest concentration of cones Fovea centralis Optic Disk: origin of the optic disk Blood vessel entry/exit Blind spot

Disorders of the Eye Emmetropia (normal vision) Myopia: nearsightnedness Hyperopia: farsightedness Colorblindness

Anatomy of the Ear External ear Collects/directs sound Pinna, external auditory meatus, ceruminous glands, tympanic membrane Middle ear (tympanic cavity) Amplify sounds Auditory tube (eustachian tube), auditory ossicles Inner ear Auditory processing/balance Oval window, bony labyrinth

Bony Labyrinth Vestibule Gravity and linear acceleration Semicircular canals Balance in 3D Continuous with vestibule Cochlea Hearing organ Cochlear duct: houses receptors to detect sound Endolymph: found in semicircular canals and cochlea Perilymph: found between bony and membranous labyrinth

Stereocilia Receptors found in ear Detect balance and sound Ampulla: swollen region in semicircular ducts Cupula: site of embedding for stereocilia

Hearing Pitch determined by region stimulated Intensity determined by how many stereocilia are stimulated Basilar membrane: site of attachment for stereocilia Tectorial membrane: stereocilia pushed into this membrane

Deafness 2 types: Conduction deafness: outer or middle ear, blocks transmission of sound All frequencies are affected Hearing aids Sensorineural deafness: neural damage or damage to the cochlea Affects quiet sounds, loud sounds might sound muffled Cochlear implant

Activity Under the notes, write a one paragraph explanation of how the eye focuses light, and how the ear processes sound and balance. Look up the following disorders and write a short description (1-2 sentences) of each disorder Macular degeneration, cataracts, and tinnitus