special senses

inner ear consists of _________, ___________ and _____________ which each contan a bony and membranous labyrinth

coche, semicircular canals, vestibule

taste buds

receptors for taste

contain gusatory cells

contain taste pores

where are taste buds located

between papilla of tongue

what activates guastory cells

taste pores

taste is a chemical sense conveyed by:

taste buds

papilla

elevations on dorsal surface of tonuge

filliform papillae

- anterior 2/3 of tonuge

- majority

- no taste buds

- detect texture and manipulate food

fungiform papilla

- tips and sides of tongue

- contain only a few taste buds each

circumvallate papilla

- inverted v at back of tonuge

- contain majority of taste buds

foliate papilla

- extend as ridges on posterior lateral sides of tonuge

- have taste buds used during childhood and infancy

________________ is a chemical sense conveyed by olfactory receptors

olfaction

eyebrows

keep sweat out of eyes

eyelashes

protect eye surface

eyelids (palperbrae)

- movable protective covering

- distribute tears during blinking

neural tunic

- provides sensory info for vision

- innermost layer containing retina

retina

- light sensitive innermost layer containing photoreceptors

- pigmented and neural layer

pigmented layer of retina

- attached to choroid

- cells absorb light energy passing through

neural layer

- deep to pigmented layer

- organized layers of cells

cells from superficial to deep of neural layer of retina

photoreceptors (rods and cones), bipolar cells, ganglion cells

direction of light through neural tunic

ganglion cells, bipolar cells, photoreceptors, pigmented layers

ora serrata

- jagged margin at end of neural layer of retina near photoreceptors

- other side has continuation of pigmented layer

photoreceptor layer of retina

- most superficial

- rods and cones

rods

- used in dim light

- >100 million per eye

- see black, white and gray

cones

- used in bright light

- <10 million per eye

- concentrated in posterior eye (fovea centralis)

- sharp and color vision

bipolar cells of retina

- middle

- synapse with photoreceptors and ganglion cells

ganglion cells

- deepest

- axons leave retina to form optic CN II

Macula Lutea

- specialized area of retina

- region lateral to optic disc

- contains fovea centralis

fovea centralis

- spot with highest density of cones

- provides sharpest vision

optic disc

- specialized area of retina where axons exit to form optic CN II

- no photoreceptors here= blind spot

lens

- focuses light onto retina (rods and cones) for vision sensory info

- attached to suspensory ligaments

- ciliary body adjusts shape for focusing

what structure divides anterior and posterior cavities of eye?

lens

anterior chamber of anterior cavity

between cornea and iris, aqueous humor

posterior chamber of anterior cavity

between iris and lens, aqueous humor

posterior cavity

between lens and retina, vitreous humor

vitreous humor

- transparent thick gelatinous material

- maintains shape of eyeball

- never replaced

iris

- colored portion of the eye -

- pupil in center

what structure contains muscles that adjust size of pupil in bright/dim light= controls how much light goes in

iris

palpebral fissure

separates eyelids

medial and lateral palpebral commissures

Unite eyelids

The two "corners" of the eye

lacrimal apparatus

produces, collects and drains lacrimal fluid (tears)

fibrous tunic

- outermost layer of eye

- provides protection and attachment sight for muscles

- cornea and sclera

sclera

- white of eye

- posterior portion of fibrous tunic

cornea

- anterior continuation of sclera (fibrous tunic)

- transparent protective covering

- bends light for focusing

vascular tunic

- vascularized to provide nourishment to cells

- middle layer of eye

- choroid, ciliary body, iris

choroid

- most extensive and posterior region

- vascularized to supply nutrients to retina

- pigmented to absorb light

ciliary body

- thick anterior portion of choroid

- focuses lens

- makes aqueous humor

suspensory ligaments

- extend from ciliary body to lens

- allow ciliary body to pull on and adjust shape of lens

auricle (pinna)

- external ear

- funnel shaped cartilaginous structure

external acoustic meatus

- the ear canal

- bony tube from pinna (auricle) to tympanic membrane

middle ear

air filled tympanic cavity

eustachian/auditory tube

- a passageway into nasopharynx

- opens to equalize pressure between middle ear and outside enviornment

what structure has to do with "popping ears"

eustachian/auditory tube

auditory ossicles

- 3 small bones in middle ear= smallest bones in body - incus, malleus, stapes

malleus

first ossicle attached to medial surface of tympanic membrane and incus

incus

middle ossicle resembling an anvil

scala vestibule of cochlea

- superior chamber

- bony labyrinth filled with perilymph

- connected to oval window

cochlear duct of cochlea

- middle chamber

- membranous labyrinth filled with endolymph

scala tympani of cochlea

- inferior chamber

- bony labyrinth filled with perilymph

- connected to round window

vestibular membrane

separates scala vestibule and cochlear duct

basilar membrane of cochlea

separates cochlear duct and scala tympani

organ of corti (spiral orgran)

- contains receptors for hearing (hair cells)

- supporting cells sit of basilar membrane within cochlear duct

hair cells

- receptor cells for hearing dispersed within supporting cells of organ of corti

hair cells send signals through _____________ neurons of vestibulocochlear CN VIII

afferent

stereocilia location and function

- embed into overlaying tectorial membrane

- bend and send signal to brain for hearing

Tectorial Membrane of the cochlea

- gel membrane within cochlear duct

- above stereocilia

semicircular canals

- part of bony labyrinth

- 3 canals that are perpendicular to each other

- detect rotational movement

- contain semicircular ducts

ampulla

bulbous region at bottom of each semicircular canal

utricle and saccule of vestibule are _____________ membranous structures that both detect the location of the __________ with respect to gravity

membranous, head

utricle of vestibule

detect horizontal movement, closest to semicircular canals

saccule of vestibule

detect vertical movement, closest to cochlea

inner walls of vestibule have thicked areas of:

hair cells

cochlear nerve

neural extensions from cochlea

vestibular nerve

neural extensions form vestibule and semicircular canals

vestibulocochlear CN VIII

formed from the joining of vestibular and cochlear nerves

olfaction

- sense of smell

- consist of olfactory neurons (CN I) that detect chemicals in air dissolved in mucus

where does olfaction occur

olfactory epithelium in superior nasal cavity

olfaction cells synapse in:

olfactory bulb

anterior cavity

cornea to lens, aqueous humor

- contains anterior and posterior chamber

stapes

last ossicle attached to incus and oval window

- lateral wall of inner ear

bony labyrinth

- inner ear

- cavities within bone

- filled with perilymph

membranous labyrinth

- inner ear

- spaces within bony labyrinth

- filled with endolymph

membranous labyrinth houses receptors for:

equilibrium and hearing

cochlea

- bony labyrinth

cochlea houses receptors for:

hearing

oval window goes __________ cochlea and round window goes _____________ cochlea

into, out of

aqueous humor

- produced by ciliary body

- provides nutrients to lens and cornea

- watery, thin

conjunctiva

- lubricate eye

- contain blood vessels to nourish cells of eyeball

tympanic membrane

- eardrum

- boundary separating external and middle ear

- thin, fragile

tympanic membrane ____________ in response to sound

vibrates

vestibule

- bony labyrinth

- contains 2 saclike membranous labyrinth structures

ocular conjuctiva

- continous lining of the external anterior surface of eye

- covers sclera NOT cornea

palpebral conjuctiva

lining of internal surface of eyelid

lacrimal caruncle

pink region in medial commissure

taste buds activate which cranial nerves?

CN VII, IX and X

pathway of taste

brainstem (synapse) --> thalamus --> insula

pathway of vision

optic CN II --> superior colliculus and thalamus --> occipital lobe

pathway of smell

olfactory bulb --> temporal lobe

auditory (sound) pathway

medulla oblongata --> pons --> inferior colliculus --> thalamus --> temporal lobe