Chapter 15A, The Special Senses, Marieb

Front 1

In the human body, 70% of all sensory receptors are located where?

Back 1

in the eye

Front 2

Most of the eye is protected by what?

Back 2

Most of the eye is protected by a cushion of fat and the bony orbit

Front 3

What are the five accessory structures of the eye?

Back 3

Accessory structures include eyebrows, eyelids, conjunctiva, lacrimal apparatus, and extrinsic eye muscles

Front 4

What are the functions of eyebrows?

Back 4

Shading the eye
Preventing perspiration from reaching the eye

Front 5

what is the function of the palpebrae?

Back 5

Protects the eye anteriorly

Front 6

What is the palpebral fissure?

Back 6

the separation between upper and lower eyelid

Front 7

what are the canthi?

Back 7

medial and lateral angles (commissures) (corners of the eye)

Front 8

what does the lacrimal caruncle contain? Where is it?

Back 8

Contains glands that secrete a whitish, oily secretion (Sandman’s eye sand). Found in the medial canthi

Front 9

What do the eyelashes do?

Back 9

initiate reflex blinking

Front 10

what is the palpebral conjunctiva?

Back 10

transparent membrane that Lines the eyelids

Front 11

What is the bulbar conjuctiva?

Back 11

transparent membrane that covers the whites of the eyes.

Front 12

what do the palpebral and conjunctiva conjunctiva do?

Back 12

Lubricates and protects the eye

Front 13

What does the lacrimal apparatus consist of?

Back 13

Consists of the lacrimal gland and associated ducts

Front 14

what do the lacrimal glands secrete?

Back 14

tears

Front 15

what do tears contain?

Back 15

Tears contain mucus, antibodies, and lysozyme

Front 16

what are the fluid inside the internal cavity of the eye called?

Back 16

Humors

Front 17

what separates the internal cavity into anterior and posterior segments?

Back 17

the lens

Front 18

Back 18

Front 19

What is the fibrous tunic composed of?

Back 19

Forms the outermost coat of the eye and is composed of:
Opaque sclera (posteriorly)
Clear cornea (anteriorly

Front 20

What is the function of the sclera?

Back 20

The sclera protects the eye and anchors extrinsic muscles

Front 21

What is the function of the cornea?

Back 21

Lets light enter the eye

Front 22

What is the vascular region of the eye called?

Back 22

The choroid region

Front 23

What are the three regions of the choroid?

Back 23

choroid, ciliary body, and iris

Front 24

Describe the structure and function of the choroid region of the eye

Back 24

A dark brown membrane that forms the posterior portion of the uvea
Supplies blood to all eye tunics

Front 25

Describe the structure and function of the ciliary body.

Back 25

A thickened ring of tissue surrounding the lens
Composed of smooth muscle bundles (ciliary muscles)
Anchors the suspensory ligament that holds the lens in place

Front 26

Why do cornea transplants work well?

Back 26

Because the cornea is avascular, so there is little chance of rejection because no blood supply reaches the area.

Front 27

What is the Iris

Back 27

The colored part of the eye

Front 28

What is the pupil?

Back 28

central opening of the iris

Front 29

What is the function of the pupil?

Back 29

Regulates the amount of light entering the eye

Front 30

When do the pupils constrict?

Back 30

during Close vision and bright light

Front 31

When do the pupils dilate?

Back 31

during Distant vision and dim light and during
Changes in emotional state – pupils dilate when the subject matter is appealing or requires problem-solving skills

Front 32

What is the retina?

Back 32

A delicate two-layered membrane lining the back part of the posterior cavity.

Front 33

What are the two layers of the retina?

Back 33

Pigmented layer and the Neural layer

Front 34

describe the pigmented layer of the retina and its function

Back 34

Pigmented layer – the outer layer that absorbs light and prevents its scattering

Front 35

describe the neural layer of the retina and its function

Back 35

Neural layer - contains photoreceptors that transduce light energy

Front 36

Identify pigmented layer, rod, cone, ganglion cells

Back 36

Front 37

What runs along the inner surface of the retina and leave the eye as the optic nerve?

Back 37

ganglion cell axons

Front 38

Describe the optic disc

Back 38

Is the site where the optic nerve leaves the eye
Lacks photoreceptors (the blind spot)

Front 39

identify pigmented layer, neural layer, optic disc, optic nerve, sclera, choroid

Back 39

Front 40

Which photoreceptors respond to dim light?

Back 40

Rods

Front 41

Which photoreceptors are used for peripheral vision?

Back 41

Rods

Front 42

Which photoreceptors respond to bright light?

Back 42

cones

Front 43

Which photoreceptors have high-acuity color vision?

Back 43

cones

Front 44

Where are cones concentrated?

Back 44

in the fovea centralis

Front 45

What is the posterior segment of the eye filled with?

Back 45

vitreous humor

Front 46

what are the four functions of vitreous humor?

Back 46

1.Transmits light
2.Supports the posterior surface of the lens
3.Holds the neural retina firmly against the pigmented layer
4.Contributes to intraocular pressure

Front 47

what are where are the two chambers of the anterior segment?

Back 47

Anterior – between the cornea and the iris
Posterior – between the iris and the lens

Front 48

What fills the anterior segment of the eye?

Back 48

aqueous humor - plasma-like fluid

Front 49

what is the function of the aqueous humor?

Back 49

Supports, nourishes, and removes wastes

Front 50

Describe the lens

Back 50

A biconvex, transparent, flexible, avascular structure, composed of epithelium and lens fibers

Front 51

what is the function of the lens

Back 51

Allows precise focusing of light onto the retina

Front 52

what happens to the lens as we age?

Back 52

With age, the lens becomes more compact and dense and loses its elasticity

Front 53

Our eyes respond to a small portion of the light spectrum called the ________ spectrum

Back 53

visible

Front 54

Different cones in the retina respond to different _________ of the visible spectrum

Back 54

wavelengths

Front 55

When light passes from one transparent medium to another its speed _______ and it ________________

Back 55

changes

refracts (bends)

Front 56

Light passing through a ___________ is bent so that the rays converge to a focal point

Back 56

convex lens (as in the eye)

Front 57

When a convex lens forms an image, the image is _________ and _________

Back 57

upside down and reversed right to left

Front 58

Describe the pathway of light entering the eye superficial to deep.

Back 58

cornea, aqueous humor, lens, vitreous humor, and the neural layer of the retina to the photoreceptors

Front 59

Where are the three places that light is refracted in the eye?

Back 59

At the cornea
Entering the lens
Leaving the lens

Front 60

What photoreceptors are responsible for black and white vision?

Back 60

rods

Front 61

What is the far point of vision?

Back 61

the distance beyond which the lens does not need to change shape to focus (20 ft.)

Front 62

What happens to the lens for distant vision?

Back 62

it is flattened by the tension from the ciliary muscle and and zonules/

Front 63

What happens to the lens for near vision

Back 63

the lens bulges as the ciliary structures relax, releasing tension

Front 64

What three things does close vision require?

Back 64

Accommodation – changing the lens shape by ciliary muscles to increase refractory power
Constriction – the pupillary reflex constricts the pupils to prevent divergent light rays from entering the eye
Convergence – medial rotation of the eyeballs toward the object being viewed

Front 65

What is an emmetropic eye?

Back 65

normal eye with light focused properly

Front 66

What term describe a nearsighted eye?

Back 66

Myopic

Front 67

in a myopic eye, where is the focal point?

How is it corrected?

Back 67

in front of the retina

with a concave lens

Front 68

what term describes a farsighted eye?

Back 68

Hyperopic

Front 69

in a hyperopic eye, where is the focal point?

How is it corrected?

Back 69

behind the retina

with a convex lens

Front 70

identify the different types of eyes

Back 70

Front 71

what are the chemical senses?

Back 71

gustation (taste) and olfaction (smell)

Front 72

in chemical senses, their chemoreceptors respond to chemicals in ________?

Back 72

aqueous solution

Taste – to substances dissolved in saliva
Smell – to substances dissolved in fluids of the nasal membranes

Front 73

How many taste buds do we have. Where are they?

Back 73

Most of the 10,000 or so taste buds are found on the tongue
Taste buds are found in papillae of the tongue mucosa

Front 74

what are the five basic taste sensations?

Back 74

Sweet – sugars, saccharin, alcohol, and some amino acids
Salt – metal ions
Sour – hydrogen ions
Bitter – alkaloids such as quinine and nicotine
Umami – elicited by the amino acid glutamate

Front 75

How much of taste is actually smell?

Back 75

80%

Front 76

See structures of the tongue

Back 76

Front 77

What else besides smell influences taste?

Back 77

Thermoreceptors, mechanoreceptors, nociceptors also influence tastes
Temperature and texture enhance or detract from taste

Front 78

What are the three parts of the ear?

Back 78

The three parts of the ear are the inner, outer, and middle ear

Front 79

Which parts of the ear are involved with hearing?

Back 79

the outer, middle and inner ear

Front 80

what part of the ear functions in equilibrium?

Back 80

inner ear

Front 81

Receptors for hearing and balance:
Respond to ________ stimuli
Are activated __________

Back 81

separate

independently

Front 83

What two things compose the auricle (pinna)

Back 83

The helix (rim)
The lobule (earlobe)

Front 84

describe the external auditory canal

Back 84

Short, curved tube filled with ceruminous glands

Front 85

Describe the tympanic membrane

Back 85

Thin connective tissue membrane that vibrates in response to sound
Transfers sound energy to the middle ear ossicles

Front 86

what is the boundary between outer and middle ears

Back 86

tympanic membrane (ear drum0

Front 87

What is the tympanic cavity and what is it flanked by?

Back 87

A small, air-filled, mucosa-lined cavity
Flanked laterally by the eardrum
Flanked medially by the oval and round windows

Front 88

What does the Pharyngotympanic tube do?

Back 88

connects the middle ear to the nasopharynx
Equalizes pressure in the middle ear cavity with the external air pressure

Front 89

what are the three ear ossicles, where are they, and what do they do?

Back 89

The tympanic cavity contains three small bones: the malleus, incus, and stapes
Transmit vibratory motion of the eardrum to the oval window

Front 90

What does the bony labyrinth contain?

Back 90

Contains the vestibule, the cochlea, and the semicircular canals
Filled with perilymph

Front 91

what is the vestibule?

Back 91

The central egg-shaped cavity of the bony labyrinth

Front 92

what is suspended in the perilymph of the vestibule?

Back 92

Suspended in its perilymph are two sacs: the saccule and utricle

Front 93

The saccule extends into the _________

Back 93

cochlea

Front 94

The utricle extends into the ________ _______

Back 94

semicircular canals

Front 95

what doe the saccule and utricle do?

Back 95

House equilibrium receptors called maculae
Respond to gravity and changes in the position of the head

Front 96

what are the semicircular canals and what do they do?

Back 96

Three canals that each lie in the three planes of space
These receptors respond to angular movements of the head

Front 97

what is the cochlea?

what does it contain?

Back 97

A spiral, conical, bony chamber that:
Contains the organ of Corti (hearing receptor)

Front 98

Back 98