17 Special Senses Nervous Flashcards
Olfactory types of cells 3 and gland 1 and where located in nose, life span
Basal cells - stem cells to replace receptors (live 1 month)
Olfactory receptor cells - odor chemicals bind to cilia
Supporting cells - columnar epithelial, support, nourishment, electrical insulation, help detoxify
Olfactory glands - bowmans glands, produce mucous
Superior nasal concha, through cribiform plate of ethmoid bone
Number receptors olfactory
10-100 million, 10,000 odors
Olfactory adaptation 2
Rapid - 50% in first second, complete insensitivity in a minute
Olfactory center in cortex
Temporal lobe 28
Extend to frontal lobe, area 11, right
Olfactory transduction
Odor molecule binds to G protein in cilia.
Produces cAMP, opens Na channel, depolarizes
Hyposmia 2
Women have keener smell than men
Reduced ability to smell with age, half over 65 and 75% over 80
Number taste buds, where 4
10,000
Most in tongue
Soft palate, pharynx, epiglottis
Types of gustatory cells 3, life span
Basal cells - produce supporting cells, develop into receptor cells. Life span 10 days
Supporting cells - contain microvilli, surround about 50 receptors, this is a taste bud
Receptors
Where are taste buds found on tongue 3
12 large circular vallate papillae, inverted V back of tongue
Fungiform papillae, entire surface of tongue
Foliate papillae - side of tongue in child
Also filiform papillae, tactile receptors, increase friction, no taste buds
Gustatory adaptation
1-5 minutes continuous stimulation
Gustatory pathway 4
Facial nerve anterior 2/3 tongue
Glossopharyngeal nerve posterior 1/3 tongue
Vagus nerve throat and epiglottis
Gustatory nucleus in medulla oblongata, primary gustatory area parietal lobe, area 43
Visible light spectrum
400-700 nm
Accessory structures eye 5
Eyelids - protect, palpebra Eyelashes Eyebrows Lacrimal (tear) apparatus Extrinsic eye muscles
Parts of outer eye 6
Pupil - under cornea, black center
Iris - constrict or dilate
Cornea - clear cover in front
Lateral/medial commissure - corners
Palpebral fissure - angle of opening of eyelids
Conjunctiva - palpebral eyelid, bulbar over sclera white
Eye glands 3
Tarsal gland, in tarsal plate connective tissue, cyst if infected
Lacrimal caruncle - sebaceous and sudoriferous
Lacrimal gland - superior lateral, bathes eye in tears, flow to medial commissure, to lacrimal puncta to lacrimal sac to nasolacrimal duct
Extrinsic eye muscles 6, nerves 3
Superior / inferior rectus
Lateral / medial rectus
Superior / inferior oblique
Oculomotor, trochlear, abducens
Anatomy layers of eyeball 3
Fibrous tunic - cornea, sclera
Vascular tunic - choroid
Retina - optic disc, rods, cones, macula lutea, fovea centralis
Middle layer of eyeball - 9
Vascular tunic - choroid, melanocytes, melanin
- ciliary body, ciliary processes, zonular fibers, ciliary muscle
- iris, pupil
Retinal layer of eyeball - 7
Optic disc
Pigmented layer, neural layer
Rods - see at night
Cones - daylight but color - RGB
Macula lutea - spot in center of posterior of eye
Fovea centralis - center of macula lutea, only cones, sharpest vision
Layers of retina neural layer 5
Ganglion cell layer Inner synaptic layer Bipolar cell layer Outer synaptic layer Photoreceptor cell layer
Detached retina 3
Trauma, blow to head
Btw neural and pigmented layers
Reattach laser or cryosurgery quickly
High level inside eyeball 6, how often replaced
Anterior cavity - anterior + posterior chamber, contains aqueous humor
Cornea to lens - anterior chamber
Ciliary body to lens, behind iris - posterior chamber
Lens to retina - vitreous chamber, contains vitreous body/humor
Aqueous humor replaced every 90 minutes
Cornea, lens, fluids refract light to hit retina
Presbyopia
Aging, lens loses elasticity, cannot read as close
Refraction abnormalities and lens to correct, normal - 4
Emmetropic eye - normal
Myopia, nearsighted - eyeball too long, concave lens
Hyperopia, hypermetropia, farsighted - eyeball too short, convex lens
Astigmatism - cornea or lens irregular curve
LASIK - laser to shape cornea
Light and dark adaptation
Light over seconds
Dark over minutes
Special senses cortex areas 4
Optic occipital, area 17
Olfactory temporal 28, extends to frontal 11
Gustatory parietal 43
Hearing temporal 41, 42
Binocular vision
Nasal or central half
Temporal or peripheral half
Nasal cross, temporal do not cross
How fast do we transduce sound
1000 times faster than photoreceptors
External ear parts 5
Auricle / pinna Lobule External auditory canal Cerumen wax Tympanic membrane
Middle ear parts 5
Auditory ossicles malleus, incus, stapes
Oval window, round window
Tensor tympani muscle limits prevents damage loud noise
Stapedius muscle smallest, dampens (hyperacusia without)
Auditory tube eustachian
Inner ear parts 3
Bony labyrinth, membranous labyrinth semicircular canal - dynamic
Saccule, utricle - static
Cochlea - hearing
Loud sounds damage
Hair cells of cochlea
90 db need hearing protectors, deafness
Formation of eyes
22 days, ectoderm to optic grooves, optic vesicles, lens placodes, optic cups, optic stalks
Ear development
22 days
Special senses and aging 6
Problems start at 50 Presbyopia - lens loses elasticity Cataracts Problems going light to dark - iris muscles weaken Glaucoma 60 Presbycusis - hearing loss 60 25%
Cataract
Loss of transparency of lens
Glaucoma 3
Most common cause of blindness, 2% over age 40
Overpressure of aqueous humor
Also normal/low tension glaucoma
Deafness
Sensorineural - hair cells, cochlear nerve
Conduction deafness - impairment outer/middle ear mechanics
Meniere’s - fluctuating hearing loss, tinnitus, vertigo. Total destruction of hearing over years.
Ageusia
Loss of sense of taste
Amblyopia
Loss of vision due to wandering eye
Anosmia
Loss of sense of smell
Miosis/mydriasis
Constriction/dilation of pupil
Nystagmus
Rapid involuntary eye movement
Tonometer
Measure eye pressure
Trachoma
Serious conjunctivitis, bacteria, single greatest cause of blindness in world
