vision and hearing

hearing

happens when something vibrates, hits eardrum and turns into electrical signals

outer ear

which part of ear catches sound?

auricle

outer part of ear where sound waves are collected and directs them into ear canal

auditory canal

carries sound from auricle to the eardrum

auditory canal

has hairs to keep dirt and bugs out; earwax to protect ear

tympanic membrane

the auditory canal leads through temporal bone to>

middle ear

what part of ear: functions to pass vibrations from eardrum to inner ear

middle ear 

what part of ear is air filled 

tympanic membrane

what part of ear: separates outer ear from middle and vibrates when sound hits it

tympanic cavity

small air space behind eardrum and contains auditory ossicles

auditory ossicles

what are these called: malleus, incus, stapes

tiny muscles 

what r these called: stapedus & tensor tympani

tiny muscles

these things help protect ear from very loud sounds by: tightening and reducing mvmnt of bones

auditory tube

connects the middle ear to the back of the throat

auditory tube

helps equalize air pressure on both sides of the eardrum (when eardrums pop)

otitis media

what is the middle ear infection also called?

otitis media 

this happens when: germs from throat travel to middle ear through eustachian tube 

eustachian tube

childrens _ is shorter and flatter than older adults

meningitis

infection of the membranes around brain and SC

inner ear 

what part of ear: functions for hearing and balance 

labyrinth

the inner ear is made of bony _

bony labyrinth

hard outer shell and filled w/ fluid

membranous labyrinth

soft, tube like system that fits inside of bony labyrinth where sensory cells for hearing and balance are found 

perilymph

fluid between bony and membranous labyrinth

endolymph

fluid inside membranous labyrinth

inner ear 

these are structures of which part of the ear: bony labyrinth, membranous labyrinth

cochlea

hearing part of inner ear (turns vibrations into merve signals)

fluid filled chambers

what are these called: scala vestibuli, scala media, scala tympani

scala vestibuli

top chamber, filled with perilymph

scala media

middle chamber filled with endolymph

scala tympani

bottom chamber, filled with perilymph

vestibular membrane 

separate scala vestibuli from cochlear duct

basilar membrane

separates cochlear duct from scala tympani

basilar membrane

spiral organ sits on top of

spiral organ

turns vibrations into nerve signals; this is the actual hearing sensor

hair cells

special sensory cells with stiff little hairs called stereocilid (hairs bend when the fluid moves)

supporting cells

help hold hair cells in place

tectorial membrane 

gel-like layer that rests on top of the sterocilia; when fluid moves, the stereocilia bends against tectorial membrane 

outer hair cells

adjust the cochleas sensitivity to dif sound frequencies and makes hearing more precise

inner hair cells

sends info to brain, main cells for hearing

conjunctiva

what accesory of the eye: is the clear mucous membrane (covers white of eye and inside eye lid) keeps eye moist, prevents dryness

lacrimal apparatus

makes,spreads, drains tears; functions to clean and lubricate eye and tears include lysosome

extrinsic eye muscles

6 muscles that move the eyeball

rectus muscles 

muscles that are: superior,inferior,lateral,medial

oblique muscles

help rotate the eyes slightly when u tilt your head, keeps vision straight

fibrous tunic

outer layer of eyeball

fibrous tunic 

layer of the eyeball: includes cornea and sclera 

vascular tunic

middle layer of eyeball

vascular tunic

layer of eyeball that includes: iris, ciliary body, choroid

inner tunic 

layer of eyeball: includes retina 

retina

contains photoreceptors that detect light

optic nerve

carries visual signals to brain

sclera 

white part of eye; tough, made of collagen to protect 

cornea

clear front part of eye; lets light enter and helps focus it

choroid

dark, blood rich layer (eye)

ciliary body

ring of muscle around lens; holds lens, helps focus it

iris

color part of eye, controls size of pupil and light entering

retina

turns light to nerve signals

optic nerve 

carries nerve signals to brain so we can see

aqueous humor 

clear watery fluid made by ciliary body

aqueous humor

fills space between iris and lens (keeps eyes shape and gives nutrients to cornea and lens)

lens

changes shape to focus light on retina (held in place by tiny fibers)

vitreous body

thick, jelly like fluid that fills space between lens and retina (helps keep eye round and holds retina in place)

cataracts 

clouding of lens

cataracts

mostly caused by aging and treated by replacing normal lens w/ plastic ones

glaucoma

happens when pressure inside eye gets too high (aqueous humor can’t drain properly) can cause death and damage of retinal cells (blind)

action potentials

retina turns light energy into _ that travel to the brain

pigmented 

what layer of retina; back layer & absorbs stray light so image stays clear 

photoreceptor

what cells: absorb light and create electrical signals

rods 

used for night vision; shades of grey

cones

work in bright light; allows color vision

bipolar

what cells: receive signals from rods & cones; passes signal forward to ganglion cells

ganglion

what cells: make the optic nerve, which sends vision to the brain

rhodopsin

visual pigment in rods (made of 2 parts) 

opsin

the protein (part of rhodopsin) triggers signal

retinal

made of vitamin A (part of rhodopsin)

photopsin

visual pigment in cones (each type absorbs dif wavelength of light) allows us to see colors

medial rectus 

1

superior oblique

2

trochlea

3

superior rectus 

4

lateral rectus

5

inferior oblique 

6

inferior rectus

7

levator palpebrae

1

superior oblique muscle

2

superior rectus muscle

3

medial rectus muscle 

4

inferior oblique muscle

6

lateral rectus muscle 

7

convergence 

the eyeballs rotate inward to focus on an object so its image falls on each fovea centralis for sharp vision

accommodation

the lens changes shape (curvature) to bend light so it focuses on retina

presbyopia

reduced ability to accomodate for near vision due to age related stiffening of the lens