Prelims

Question 1

shade the eyes during sleep, protect the eyes from excessive light and foreign objects, and spread lubricating secretions over the eyeballs.

Answer 1

eyelids

Question 2

gives form and support to the eyelids.

Answer 2

tarsal plate

Question 3

secrete a fluid to keep the eyelids from adhering to each other.

Answer 3

tarsal glands

Question 4

is a thin mucous membrane that lines the inner aspect of the eyelids and is reflected onto the anterior surface of the eyeball.

Answer 4

conjunctiva

Question 5

help protect the eyeballs from foreign objects, perspiration, and the direct rays of the sun.

Answer 5

eyelashes and eyebrows

Question 6

consists of structures that produce and drain tears

Answer 6

lacrimal apparatus

Question 7

move the eyeballs laterally, medially, superiorly, and inferiorly.

Answer 7

six extrinsic eye muscles

Question 8

contains the nonvascular lens, just behind the pupil and iris.

Answer 8

eyeball

Question 9

the “white” of the eye, is a white coat of dense fibrous tissue that covers all the eyeball, except the most anterior portion, the iris; the sclera gives shape to the eyeball and protects its inner parts. Its posterior surface is pierced by the optic nerve.

Answer 9

sclera

Question 10

is a nonvascular, transparent, fibrous coat through which the iris can be seen;
the cornea acts in the refraction of light.

Answer 10

cornea

Question 11

is the middle layer of the eyeball and is composed of three portions:
choroid, ciliary body, and iris.

Answer 11

Vascular tunic

Question 12

absorbs light rays so that they are not reflected and scattered within

Answer 12

choroid

Question 13

is the colored portion seen through the cornea and consists of the circular iris and radial iris smooth muscle fibers (cells) arranged to form a doughnut-shaped structure.

Answer 13

iris

Question 14

The third and inner coat of the eye, the BLANK (nervous tunic), lines the posterior three-quarters of the eyeball and is the beginning of the visual pathway.

Answer 14

retina

Question 15

neurons are called rods or cones because of the different shapes of their outer segments.

Answer 15

photoreceptors

Question 16

specialized for black-and-white vision in dim light; they also allow us to discriminate between different shades of dark and light and permit us to see shapes and movement.

Answer 16

rods

Question 17

are specialized for color vision and sharpness of vision (high visual acuity) in bright light; cones are most densely concentrated in the central fovea, a small depression in the center of the macula lutea. The macula lutea is in the exact center of the posterior portion of the retina, corresponding to the visual axis of the eye.

Answer 17

Cones

Question 18

is the area of sharpest vision because of the hinh concentration of cones.

Answer 18

fovea

Question 19

subdivided into the anterior chamber (which lies behind the cornea and in front of the iris) and the posterior chamber (which lies behind the iris and in front of the suspensory ligaments and lens).

Answer 19

anterior cavity

Question 20

The second, and larger, the cavity of the eyeball is the Blank (posterior cavity). It lies between the lens and the retina and contains a gel called the vitreous body. It is formed during embryonic life and is not replaced thereafter.

Answer 20

vitreous chamber

Question 21

The bending of light rays at the interface of two different media is called

Answer 21

refraction

Question 22

is an increase in the curvature of the lens, initiated by ciliary muscle contraction, which allows the lens to focus on near objects. To focus on far objects, the ciliary muscle relaxes, and the lens flattens.

Answer 22

accommodation

Question 23

is nearsightedness.

Answer 23

Myopia

Question 24

is farsightedness.

Answer 24

Hyperopia

Question 25

is a refraction abnormality due to an irregular curvature of either the cornea or lens.

Answer 25

astigmatism

Question 26

are colored proteins that undergo structural changes upon light absorption.

Answer 26

photopigments

Question 27

transmit excitatory signals to ganglion cells, which depolarize and initiate nerve impulse

Answer 27

Bipolar Cells

Question 28

(hearing and equilibrium) collects sound waves and passes them inwards; it consists of the auricle (pinna), the external auditory canal (meatus), and tympanic membrane (eardrum)

Answer 28

External Ear

Question 29

(hearing and equilibrium) is a small, air-filled cavity in the temporal bone that is lined by epithelium. It contains the auditory (Eustachian) tube, auditory ossicles (middle ear bones, the malleus, incus, and stapes), the oval window, and the round window.

Answer 29

Middle ear

Question 30

(hearing and equilibrium) is also called the labyrinth because of its complicated series of canals. Structurally it consists of two main divisions: an outer bony labyrinth that encloses an inner membranous labyrinth.

Answer 30

Internal Ear

Question 31

is a series of cavities in the petrous portion of the tempora bone.

Answer 31

Bony labyrinth

Question 32

is related to differences in the width and stiffness of the basilar membrane and sound waves of various frequencies that cause specific regions of the basilar membrane to vibrate more intensely than others.

Answer 32

pitch

Question 32

(hearing and equilibrium) is also called the labyrinth because of its complicated series of canals. Structurally it consists of two main divisions: an outer bony labyrinth that encloses an inner membranous labyrinth.

Answer 32

Internal Ear

Question 33

Nerve impulses from the cochlear branch of the vestibulocochlear nerve pass to the cochlear nuclei in the medulla. Here, most impulses cross to the opposite side and then travel to the midbrain, to the thalamus, and finally to the auditory area of the temporal lobe of the cerebral cortex.

Answer 33

Auditory Pathway

Question 35

2 kinds of equilibrium

Answer 35

Static equilibrium Dynamic equilibrium

Question 36

(2 kinds of equilibrium) refers to the maintenance of the position of the body (mainly the head) relative to the force of gravity.

Answer 36

Static equilibrium

Question 37

(2 kinds of equilibrium) is the maintenance of body position (mainly the head) in response to sudden movements, such as rotation, acceleration, and deceleration.

Answer 37

Dynamic equilibrium