15.2-15.4 Eye/Ear Physiology

Question 1

Packets of energy (photons) that travel in wavelike fashion at high speeds
Visible light can be broken up into bands of colors
Color that the eye perceives is a reflection of a particular wavelength

Answer 1

Light

Question 2

How does light travel?

Answer 2

Straight lines
Blocked by transparent objects

Question 3

Seeing black; seeing white

Answer 3

Lack of reflection (absorbs all color); all reflection (no absorbtion)

Question 4

Bending of light rays; Due to speed of light when it passes from one transparent medium to another and path of light is at an oblique angle

Answer 4

Refraction

Question 5

Good at refracting light because they are curved on one or both sides
Disc part of eye

Answer 5

Lens

Question 6

Thicker in center than edges
Bend light passing through it, so that rays converge at a single point (focal point)
More convex the lens, more light that bends, shorter focal distance

Answer 6

Convex

Question 7

Thicker at edges than in center
Disperse light

Answer 7

Concave lens

Question 8

Image is _____ and ______ but brain corrects it in light refraction

Answer 8

Upside-down; backwards

Question 9

Cornea –> Aqueous humor–> Lens–> Vitreous humor–> Neural layer (retina)–> Photoreceptors

Answer 9

Pathway of light

Question 10

Light is refracted ____ times

Answer 10

3
Entering cornea, Entering lens, Leaving lens

Question 11

Part of eye where majority of refractory power is
Constant, cannot change focus

Answer 11

Cornea

Question 12

Eyes are best adapted for this type of vision
Ciliary muscles completely relaxed
Lens flattened from pulling on ciliary zonules

Answer 12

Distant vision

Question 13

State of vision where a faraway object at infinity is in sharp focus with the eye lens in a neutral or relaxed state
Normal eye

Answer 13

Emmetropia (normal)

Question 14

Changing of lens shape to increase refraction (focusing)
Ciliary muscle contracts, zonules loosen, lens bulges

Answer 14

Accommodation of the lens

Question 15

Constriction of pupils to prevent most divergent light rays from entering eye
Sphincter pupillae accomplish this

Answer 15

Constriction of pupil

Question 16

Medial rotation of eyeballs causes convergence of eyes toward object being viewed

Answer 16

Convergence of eyballs

Question 17

Normal eye

Answer 17

Emmotropic eye

Question 18

Eyeball is too long, so focal point is in front of retina
Corrected with concave lens

Answer 18

Myopia (nearsighted)

Question 19

Eyeball is too short, so focal point is behind retina
Corrected with a convex lens to converge light stronger

Answer 19

Hyperopia (farsighted)

Question 20

Unequal curvatures in different parts of the cornea
Causes smeared look in lights especially at night
Corrected with cylindrically ground lenses or laser procedures

Answer 20

Astigmatism

Question 21

Loss of accommodation over 50

Answer 21

Presbyopia

Question 22

Modified neurons involved in vision (type of receptor)
Includes rods and cones

Answer 22

Photoreceptors

Question 23

Light recieving region of photoreceptors
Plasma memebrane of outer segment folds back to form many discs
Dics contain visual pigments that change shape when absorbing light

Answer 23

Outer segment

Question 24

Site of metabolism and maintenance of membrane potential in photoreceptor

Answer 24

Inner segment

Question 25

Consist of retinal combined with proteins called opsins

Answer 25

Visual pigments

Question 26

Key light absorbing molecule Synthesized from vitamin A Absorbs different visual wavelengths depending on which opsin it is bound to

Answer 26

Retinal

Question 27

4 opsins only in rods

Answer 27

Rhodopsins

Question 28

3 opsins found in cones Names are based on colors they absorb best

Answer 28

Green, blue, red

Question 29

Require bright light for activation React more quickly than rods Less sensitive than rods Non Converging pathways occur here

Answer 29

Cones

Question 30

We see dimly lit objects best we do not look at them directly and they are _________

Answer 30

Moving

Question 31

Lack of one or more cone pigments Inherited as an X-linked condition, more common in males Common type = red-green

Answer 31

Color blindness

Question 32

Process by which light energy is converted into a graded receptor potential (5 part relay race) Begin when a visual pigment captures a photon of light Retinol is bent from dark, but straightens out when light is present

Answer 32

Phototransduction

Question 33

When moving from darkness into bright light we see a glare Both rods and cones are on, pupils contrict Improves over 5-10 minutes

Answer 33

Light adaptation

Question 34

When moving from bright light into dim light, we see blackness Cones stop functioning Rods are off Pupils dilate Increases sensitivity over 20-30 minutes

Answer 34

Dark adaptation

Question 35

Condition in which rod function is seriously hampered Driving at night is impaired

Answer 35

Nyctalopia

Question 36

Pressure disturbance produced by a vibrating object and propagated by molecules of the medium

Answer 36

Sound

Question 37

Created when an object moves; Creates areas of high pressure and low pressure (compressions and rarefactions)

Answer 37

Sound waves

Question 38

An area of low pressure due to presence of fewer air molecules

Answer 38

Rarefaction

Question 39

Number of waves that pass given point in a given time Perceived as a pitch Most sounds are mixtures of different frequencies (High pitched vs. low pitched)

Answer 39

Frequency

Question 40

Height of wave crests (Loud vs. soft)

Answer 40

Amplitude

Question 41

Reception of an air sound wave that is converted to a fluid wave that ultimately stimulates mechanosensitive cochlear hair cells that send impulses to the brain for interpretation

Answer 41

Hearing

Question 42

Higher the intensity, the _____ vibration

Answer 42

Higher

Question 43

Typanic membrane is _______ times larger than oval window, so vibration transferred to oval window is 20x amplified

Answer 43

20

Question 44

Sound waves end here and bulges outward into middle ear cavity

Answer 44

Round window

Question 45

Blocked sound conduction to fluids of internal ear Causes include impacted wax, perforated eardrum, otitis media, otosclerosis of the ossicles (fusing)

Answer 45

Conduction deafness

Question 46

Damage to neutral structures Typically from hair cell loss: Gradual loss of cells throughout life Single explosive loud noise, or prolonged exposure to high intensity sounds

Answer 46

Sensorineural deafness

Question 47

Helps to collect sound and direct it into auditory canal

Answer 47

Ear trumpet

Question 48

Amplifies sound, has a microphone, amplifier, and speaker

Answer 48

Hearing aid

Question 49

Convert sound energy into electrical signals Are effective for congenital or age/noise cochlear damage

Answer 49

Cochlear implants

Question 50

Ringing, buzzing, or clicking sound in ears in absence of auditory stimuli Due to cochlear nerve degeneration, inflammation of middle or internal ears, side affects of aspirin

Answer 50

Tinnitus

Question 51

Labyrinth disorder that affects cochlea and semicircular canals Causes vertigo, nausea, and vomiting Treatment: Anti-motion sickness drugs in mild cases or surgical removal of labyrinth in severe cases

Answer 51

Meinier's Syndrome