Chapter 17: Sense Organs Eye and Ear: Vocabulary

Question 1

accommodation

Answer 1

Normal adjustment of the eye to focus on objects from far to near

Question 2

anterior chamber

Answer 2

Area behind the cornea and in front of the lens and iris. Contains aqueous humor

Question 3

aqueous humor

Answer 3

Fluid produced by the ciliary body and found in the anterior chamber

Question 4

humor

Answer 4

Any body fluid, including blood and lymph

Question 5

biconvex

Answer 5

Consisting of two (2) surfaces that are rounded, elevated, and curved evenly, like part of a sphere

Question 6

choroid

Answer 6

Middle, vascular layer of the eye, between the retina and the sclera

Question 7

ciliary body

Answer 7

Structure on each side of the lens that connects the choroid and iris. It contains ciliary muscles, which control the shape of the lens and it secretes aqueous humor

Question 8

cone

Answer 8

Photoreceptor cell in the retina that transforms light energy into a nerve impulse. Responsible for colour and central vision

Question 9

conjunctiva

Answer 9

Delicate membrane lining the eyelids and covering the eyeball

Question 10

cornea

Answer 10

Fibrous transparent layer of clear tissue that extends over the anterior portion of the eyeball

Question 11

fovea centralis

Answer 11

Tiny pit or depression in the retina that is the region of the clearest vision

Question 12

fundus of the eye

Answer 12

Posterior, inner part of the eye

Question 13

iris

Answer 13

Pigmented (coloured) layer that opens and closes to allow more or less light into the eye

Question 14

lens

Answer 14

Transparent, biconvex body behind the pupil of the eye. It bends (refracts) light rays to bring them into focus on the retina

Question 15

macula

Answer 15

Yellowish region on the retina lateral to and slightly below the optic disc; contains the fovea centralis

Question 16

optic chiasm

Answer 16

Point at which the optic nerve fibers cross in the brain

Question 17

optic disc

Answer 17

Region at the back of the eye where the optic nerve meets the retina. It is the blind spot in the eye because it contains only nerve fibers, no rods or cones, and is thus insensitive to light

Question 18

optic nerve

Answer 18

Cranial nerve carrying impulses from the retina to the brain (cerebral cortex)

Question 19

pupil

Answer 19

Central opening of the eye, surrounded by the iris, through which light rays pass

Question 20

refraction

Answer 20

Bending of light rays by the cornea, lens, and fluids of the eye to bring the rays into focus on the retina

Question 21

retina

Answer 21

Light-sensitive nerve cell layer of the eye containing photoreceptor cells (rods and cones)

Question 22

rod

Answer 22

Photoreceptor cell of the retina essential for vision in low light and for peripheral vision

Question 23

sclera

Answer 23

Tough, white outer coat of the eyeball

Question 24

thalamus

Answer 24

Relay centre of the brain. Optic nerve fibers pass through the thalamus on their way to the cerebral cortex

Question 25

vitreous humor

Answer 25

Soft, jelly-like material behind the lens in the vitreous chamber; helps maintain the shape of the eyeball

Question 26

auditory canal

Answer 26

Channel that leads from the pinna to the eardrum

Question 27

auditory meatus

Answer 27

Auditory canal

Question 28

auditory nerve fibers

Answer 28

Carry impulses from the inner ear to the brain (cerebral cortex). These fibers compose the vestibulocochlear nerve

Question 29

auditory tube

Answer 29

Channel between the middle ear and the nasopharynx; eustachian tube

Question 30

auricle

Answer 30

Flap of the ear; the protruding part of the external ear, or pinna

Question 31

cerumen

Answer 31

Waxy substance secreted by the external ear; earwax

Question 32

cochlea

Answer 32

Snail shell-shaped, spirally wound tube in the inner ear; contains hearing-sensitive receptor cells

Question 33

endolymph

Answer 33

Fluid within the labyrinth of the inner ear

Question 34

eustachian tube

Answer 34

Auditory tube

Question 35

incus

Answer 35

Second ossicle (small bone) of the middle ear

Question 36

labryinth

Answer 36

Maze-like series of canals of the inner ear. This includes:

• cochlea
• vestibule
• semicircular canals

Question 37

malleus

Answer 37

First ossicle of the middle ear

Question 38

organ of Corti

Answer 38

Sensitive auditory receptor area found in the cochlea or the inner ear

Question 39

ossicle

Answer 39

Small bone of the ear; includes:

• malleus
• incus
• stapes

Question 40

oval window

Answer 40

Membrane between the middle ear and the inner ear

Question 41

perilymph

Answer 41

Fluid contained in the labyrinth of the inner ear

Question 42

pinna

Answer 42

Auricle; flap of the ear

Question 43

semicircular canals

Answer 43

Passages in the inner ear associated with maintaining equilibrium

Question 44

stapes

Answer 44

Third ossicle of the middle ear

Question 45

tympanic membrane

Answer 45

Membrane between the outer and the middle ear; also called the eardrum

Question 46

vestibule

Answer 46

Central cavity of the labyrinth, connecting the semicircular canals and the cochlea. Contains the saccule and utricle to help maintain equilibrium

Question 47

uvea

Answer 47

Contains:

• choroid
• iris
• ciliary body