Chapter 15 - Eye & Ear

Question 1

The barrier between the outer ear and middle ear

Answer 1

tympanic membrane

Question 2

sound energy is converted to ___ energy by the ___

Answer 2

mechanical energy; tympanic membrane

it’s mechanical energy because the tympanic membrane vibrates, and that mechanical energy can then be transferred to the auditory ossicles

Question 3

the pharyngotympanic tube connects the middle ear to the ___

Answer 3

nasopharynx (back of nasal cavity)

Question 4

physiology of pharyngotympanic tube

Answer 4

• allows us to equalize pressure across tympanic membrane when the tube is opened by yawning, chewing, etc.
• this is important because tympanic membrane cannot vibrate properly unless pressure is equalized

Question 5

___ window is deep to stapes

Answer 5

oval window is deep to stapes

Question 6

which of the auditory ossicles articulates with both of the other two?

Answer 6

incus

Question 7

name the muscles that suspend the auditory ossicles and physiology

Answer 7

tensor tympani - longer, attached to malleus
stapedius - shorter, attached to stapes
when they contract due to loud sounds, they dampen the vibrations to prevent damage to inner ear structures

Question 8

name the three parts of the bony labyrinth

Answer 8

vestibule, semicircular canals, cochlea

Question 9

which division of the ear is responsible for both hearing and equilibrium?

Answer 9

inner ear

Question 10

What is the structure inside the bony labyrinth called? What does it contain?

Answer 10

the membranous labyrinth, which contains K+ - rich endolymph

Question 11

which two structures make up the vestibular apparatus?

Answer 11

semicircular canals and vestibule

Question 12

which of the membranous sacs in the vestibule is closer to the cochlea?

Answer 12

saccule is continuous with cochlear duct

Question 13

through which nerve is information sent back to the central nervous system from the maculae of the inner ear?

Answer 13

vestibulocochlear (VIII)

Question 14

what are the hairlike structures on the hair cell called?

Answer 14

stereocilia; the one with the bulb is the kinocilium responsible for relaying info to the vestibular nerve

Question 15

What is on the surface of the jello-like membrane in the maculae of inner ear?

Answer 15

Otoliths, which are basically heavy little rocks made of CaCO3 on the surface of the otolith membrane. These increase the inertia of the membrane.

Question 16

what causes the stereocilia of the macula to bend back or forth?

Answer 16

movement of the head causes the otolith membrane to slide back and forth. Since the hair cells’ tips are embedded in the otolith membrane, they bend when the membrane slides

Question 17

when stereocilia bend ___ the kinocilium, channels ___

Answer 17

towards, open;

away, close

Question 18

when the head tilts ___, the frequency of APs fired ___

Answer 18

forward, increases- due to hairs bending toward kinocilium;

backward, decreases due to hairs bending away from kinocilium

Question 19

This transparent membrane covers the eye and provides lubrication. The palpebral part extends under the eyelids and the bulbar part covers the whites of the eye.

Answer 19

conjuctiva

Question 20

The______ produces & secretes tears which enter the conjuctival sac via secretory ducts. Blinking moves tears down and across the eyeball where they enter the _______ punctum & canaliculi, eventually draining into the ________ sac and nasolacrimal duct.

Answer 20

lacrimal gland, lacrimal, lacrimal (all part of lacrimal apparatus).

Question 21

The superior and inferior rectus eye muscles elevate and depress the eye, respectively, but they also turn the eye which direction: laterally or medially?

Answer 21

Medially

Question 22

The superior and inferior oblique eye muscles ______ and _______ the eye, but they also turn the eye laterally.

Answer 22

depress, elevate

Question 23

The ______ tunic is the outer layer of the eye, consisting of the _____ and ______.

Answer 23

fibrous, sclera & cornea

Question 24

The transparent, anterior 1/6th portion of the fibrous tunic allows light to enter the eye and contains many pain receptors.

Answer 24

Cornea

Question 25

The part of the fibrous tunic covers the posterior 5/6 of the fibrous tunic and is continuous with the dura mater of the brain.

Answer 25

Sclera

Question 26

The _____ tunic is the middle, pigmented layer of the eye consisting of the choroid, ciliary body, lens, and iris.

Answer 26

vascular

Question 27

These smooth muscles control the shape of the lens. When relaxed the muscle is wider, the lens becomes thin and focused for distant vision. When contracted, the lens becomes thick and focused for short vision.

Answer 27

Ciliary muscles

Question 28

Cataracts are caused by the clumping of crystalline proteins in this biconvex structure.

Answer 28

Lens

Question 29

_______ ligaments attached to _______ muscles help control the shape of the lens.

Answer 29

Suspensory, ciliary; these make up the ciliary body

Question 30

This dark posterior region absorbs light and contains many blood vessels supplying blood to all layers of the eye.

Answer 30

Choroid

Question 31

This colored part of the eye separates the cornea and the lens, and controls the opening/closing of the pupil.

Answer 31

Iris

Question 32

The _________ nervous system innervates the sphincter pupillae of the iris and when it contracts, causes the pupil to constrict.

Answer 32

parasympathetic

Question 33

The _________ nervous system innervates the dilator pupillae of the iris and when it contracts, causes the pupil to dilate.

Answer 33

sympathetic

Question 34

The _______ tunic consist of the retina, which contains_____% of the body's sensory receptors.

Answer 34

nervous, 70%

Question 35

The outer pigmented layer stores vitamin A and transfers it to photoreceptors in the inner neural layer of the _______.

Answer 35

Retina

Question 36

These photoreceptors are for peripheral vision and dim light, and also do not detect color.

Answer 36

Rods

Question 37

There are 3 types of this photoreceptor, important in bright light, central vision, and high resolution colors.

Answer 37

Cones

Question 38

Lateral to the optic disc blind spot, this structure contains mostly cones with a tiny pit called the fovea centralis. Here we have our sharpest vision.

Answer 38

Macula lutea

Question 39

The anterior segment, the area in front of the lens, is filled with__________.

Answer 39

Aqueous humor

Question 40

The posterior segment, the area behind the lens, is filled with ________, which helps keep the shape of the eye and holds the retina against the choroid.

Answer 40

Vitreous humor

Question 41

The structures are actually modified neurons consisting of a cell body, synaptic terminal, and an inner and outer segment.

Answer 41

Rods and cones

Question 42

_____ is the key light absorbing molecule in photoreceptors. It combines with opsins to form pigments.

Answer 42

Retinal

Question 43

Process by which a pigment captures light energy and converts it into a graded receptor potential

Answer 43

phototransduction

Question 44

Summarize steps of phototransduction

Answer 44

1. Retinal absorbs light and changes shape, activating visual pigment 2. Visual pigments activates transducin (a G-protein) 3. Transducin activates phosphodiesterase 4. Phosphodiesterase coverts cGMP to GMP, causing cGMP levels to fall 5. When cGMP levels fall, cGMP gated cation channels, close, causing hyperpolarization

Question 45

tiplinks close when the head is tilted ___

Answer 45

backwards, because the tiplinks are looser and the mechanically-gated channels can close, hyperpolarizing the hair cell

Question 46

___ maculae are oriented horizontally, and detect head movement in the horizontal plane

Answer 46

utricle

Question 47

saccule maculae respond to ___ movement

Answer 47

vertical

Question 48

___ are the enlarged regions of each semicircular canal

Answer 48

ampulla

Question 49

inside the ampulla are ___ which contain ___

Answer 49

``` crista ampullaris; hair cells extending to the ampullary culpula (gelled mass) ```

Question 50

how do the semicircular canals detect movement?

Answer 50

when endolympth moves past the ampullary cupula, that moves the hair bundles with their stereocilia and kinocilium

Question 51

Semicircular canals detect rotational movement during the entire movement. True or False?

Answer 51

False; they detect when the rotational movement starts and stops

Question 52

the ___ window's function is pressure release

Answer 52

round

Question 53

list the structures that sound waves (or fluid waves) pass through in order (if it's within the hearing range)

Answer 53

tympanic membrane, malleus, incus, stapes, oval window, scala vestibuli, cochlear duct, scala tympani; movement through cochlear duct is what causes hair cells to bend

Question 54

the organ of ___ is where sound information is actually transduced

Answer 54

organ of corti (spiral organ) within the scala media chamber

Question 55

which chambers are filled with perilymph?

Answer 55

scala vestibuli | scala tympani

Question 56

cochlear hairs in the spiral organ are embedded in the ___

Answer 56

tectorial membrane

Question 57

with vibrations, the ___ membrane vibrates while the ___ membrane stays stationary

Answer 57

basilar; tectorial

Question 58

how do we hear different sound frequencies?

Answer 58

location of the vibration on the basilar membrane -- low-frequency sounds vibrate floppy fibers at the apex; high-frequency sounds vibrate the stiff fibers near the base

Question 59

when tip links are pulled, what type of channels open?

Answer 59

mechanically-gated ion channels

Question 60

what two important functions do the outer hair cells do?

Answer 60

1) contract to amplify motion of basilar membrane for fine-tuned hearing 2) relax to decrease motion of the basilar membrane to protect the inner hair cells from bending too far