Ch. 15 - The Special Senses

Front 1

1. vision

2. taste

3. smell

4. hearing

5. equilibrium

Back 1

5 special senses

Front 2

special sensory receptors

Back 2

distinct receptor cells that are highly localized, and housed in complex organs (eyes and ears) or structures (taste buds, olfactory epithelium)

Front 3

1. eyebrows

2. eyelids

3. conjunctiva

4. lacrimal apparatus

5. extrinsic eye muscles

Back 3

5 accessory structures of the eye

Hint 3

Front 4

eyebrows

Back 4

short, coarse hairs that help protect the eyes from sunlight and perspiration

Hint 4

Front 5

eyelids (palpebrae)

Back 5

protect the anterior portion of the eyes

Hint 5

Front 6

palpebral fissure

Back 6

the slit separating the upper and lower eyelids

Hint 6

Front 7

commisures

Back 7

medial and lateral angles of the eye

Hint 7

Front 8

lacrimal caruncle

Back 8

the fleshy elevation of the medial commissure that contains sebaceous and sweat glands; whitish oily secretion ("Sandman's eye sand")

Hint 8

Front 9

eyelashes

Back 9

richly innervated hairs projecting from the free margin of each eyelid; extremely sensitive to touch

Hint 9

Front 10

tarsal glands

Back 10

glands that secrete an oily secretion that lubricates the eyelid and eye

Hint 10

Front 11

conjunctiva

Back 11

transparent mucous membrane lining the anterior eye (except the cornea) and inner eyelids

Hint 11

Front 12

lacrimal apparatus

Back 12

consists of the lacrimal gland and the ducts that drain lacrimal secretions into the nasal cavity

Hint 12

Front 13

lacrimal gland

Back 13

orbital gland that secretes tears; superior and lateral to the eye

Hint 13

Front 14

lacrimal secretion (tears)

Back 14

secretion that cleans, protects, and lubricates the eyes

Hint 14

Front 15

lysozyme

Back 15

lacrimal fluid enzyme that destroys bacteria

Front 16

lacrimal canal

Back 16

drain for lacrimal secretions, run from the lacrimal sac into the nasolacrimal duct (nasal cavity)

Hint 16

Front 17

extrinsic eye muscles

Back 17

six straplike muscles that control eyeball movement

Hint 17

Front 18

1. lateral rectus

2. medial rectus

3. superior rectus

4. inferior rectus

5. inferior oblique

6. superior oblique

Back 18

6 extrinsic eye muscles

Hint 18

Front 19

1. oculomotor (III)

2. trochlear (IV)

3. abducens (VI)

Back 19

3 cranial nerves that innervate the extrinsic eye muscles

Front 20

diplopia

Back 20

double vision

Front 21

1. fibrous layer

2. vascular layer

3. inner layer

Back 21

3 layers of the eyeball

Hint 21

Front 22

fibrous layer (tunic)

Back 22

outermost layer of the eyeball; dense avascular connective tissue

Hint 22

Front 23

1. sclera

2. cornea

Back 23

2 regions of the fibrous layer of the eyeball

Hint 23

Front 24

sclera

Back 24

white part of the eye; continuous with the dura mater of the brain

Hint 24

Front 25

cornea

Back 25

transparent, anterior portion of the fibrous layer of the eye; consists of collagen fibers, refracts light

Hint 25

Front 26

1. sensitive

2. regenerates quickly

3. avascular

Back 26

3 important characteristics of the cornea

Front 27

vascular layer (tunic)

Back 27

pigmented middle layer of the eyeball

Hint 27

Front 28

1. choroid

2. ciliary body

3. iris

Back 28

3 regions of the vascular layer of the eye

Hint 28

Front 29

choroid

Back 29

highly vascular, dark brown membrane forming the posterior 5/6 of the vascular tunic; absorbs light (preventing it from scattering)

Hint 29

Front 30

ciliary body

Back 30

ring of tissue in the vascular layer of the eye that encircles the lens

Hint 30

Front 31

ciliary muscles

Back 31

smooth muscle controlling the shape of the lens

Front 32

ciliary processes

Back 32

posterior folds of the ciliary body that secrete aqueous humor

Hint 32

Front 33

ciliary zonules (suspensory ligaments)

Back 33

ligaments that connect the ciliary body to the lens, suspending it

Hint 33

Front 34

iris

Back 34

visible colored portion of the eye that controls pupil size

Hint 34

Front 35

pupil

Back 35

round central opening of the eye that controls the amount of light entering; ANS controlled

Hint 35

Front 36

retina (sensory layer)

Back 36

innermost layer of the eyeball

Hint 36

Front 37

1. pigmented layer

2. neural layer

Back 37

2 layers of the retina

Hint 37

Front 38

pigmented layer

Back 38

outer layer of the retina that absorbs light and prevents it from scattering; abuts the choroid

Hint 38

Front 39

neural layer

Back 39

inner layer of the retina that transduces (converts) and transmits the visual signal

Hint 39

Front 40

1. photoreceptors

2. bipolar cells

3. ganglion cells

Back 40

3 types of neurons forming the neural layer of the retina

Hint 40

Front 41

photoreceptors

Back 41

outer neuron cells of the neural layer of the retina; contains rods and cones

Hint 41

Front 42

1. rods

2. cones

Back 42

2 types of photoreceptors in the eye

Hint 42

Front 43

rods

Back 43

photoreceptors for dim light (black and white)

Hint 43

Front 44

cones

Back 44

photoreceptors for bright light and high-resolution color vision

Hint 44

Front 45

bipolar cells

Back 45

middle cells of the neural layer of the retina; transmit signals from photoreceptors to ganglion cells

Hint 45

Front 46

ganglion cells

Back 46

innermost cells of the neural layer of the retina; generate action potentials through their axons (the optic nerve)

Hint 46

Front 47

optic disc

Back 47

where the optic nerve leaves the eye, 20% off center; blind spot because it has no photoreceptors

Hint 47

Front 48

macula lutea

Back 48

posterior center of the eye; high concentration of cones (acute vision)

Hint 48

Front 49

fovea centralis

Back 49

center of the macula lutea; highest concentration of cones

Hint 49

Front 50

vitreous humor

Back 50

clear viscous gel that maintains the shape of the eye; fills the posterior cavity (behind the lens)

Hint 50

Front 51

aqueous humor

Back 51

clear fluid that provides nutrients and O2 to the lens and cornea; fills the anterior cavity (around and in front of the lens)

Hint 51

Front 52

canal of Schlemm (scleral venous sinus)

Back 52

canal encircling the eye that returns aqueous humor to the blood

Hint 52

Front 53

glaucoma

Back 53

caused by blocked drainage of aqueous humor that compresses the retina and optic nerve

Front 54

lens

Back 54

flexible structure that changes shape to focus light on the retina; avascular

Hint 54

Front 55

crystallins

Back 55

tightly packed, transparent proteins that form the body of the lens

Front 56

cataract

Back 56

clouding of the lens caused by hardening or thickening of the lens (crystallins clumping together)

Hint 56

Front 57

visible light

Back 57

part of the electromagnetic spectrum that eyes respond to; small particles called photons

Front 58

refraction

Back 58

the bending of light as it passes through different mediums

Front 59

- cornea

- aqueous humor

- lens

- vitreous humor

- retina

- photoreceptors

Back 59

trace the path of light as it enters the eye (6 areas)

Hint 59

Front 60

distant vision

Back 60

vision of parallel light; the cornea refracts the light

Front 61

close vision

Back 61

vision of diverging light; the lens must also refract the light, in addition to the cornea

Front 62

myopia (nearsightedness)

Back 62

when distant objects focus in front of the retina, rather than on it; eyeball is too long

Hint 62

Front 63

hyperopia (farsightedness)

Back 63

when objects focus behind the retina; eyeball is too short

Hint 63

Front 64

astigmatism

Back 64

blurry images caused by unequal curvature in different parts of the cornea or lens

Front 65

retinal

Back 65

a light-absorbing molecule that changes shape when exposed to light; comes from vitamin A

Front 66

opsin

Back 66

protein attached to retinal; 1 type for rods, 3 types for cones

Front 67

rhodopsin

Back 67

the photopigment of rods; breaks down in light, increases with dark

Front 68

light adaptation

Back 68

light completely bleaches rhodopsin, so cones take over; moving from darkness to light

Front 69

dark adaptation

Back 69

rod's rhodopsin accumulates in the dark, and cones cannot function; moving from light to darkness

Front 70

optic nerve (CN II)

Back 70

nerve formed by axons from the ganglion cells of the eye

Front 71

optic chiasma

Back 71

the point where fibers from the medial eye cross over to the opposite side; the right visual field heads to the left optic tract and left visual cortex, and vice versa

Front 72

optic tract

Back 72

the bundle of fibers carrying information from the visual field to the thalamus

Front 73

visual cortex

Back 73

responsible for conscious perception of a visual image; located in the occipital lobe

Front 74

superior colliculi

Back 74

area of the midbrain responsible for visual reflexes (head and eye movements)

Front 75

stereoscopic vision (binocular vision)

Back 75

the same image seen from different angles allows for depth perception

Front 76

thalamus

Back 76

area of the brain that receives input from both eyes; detects movement and depth perception

Front 77

primary visual cortex

Back 77

area of the brain that forms a topographical map of the retina

Front 78

visual association area

Back 78

area of the brain that interprets dynamic images, form, color, depth, and motion

Front 79

chemoreceptors

Back 79

receptors that respond to chemicals in an aqueous solution; smell and taste

Front 80

olfactory epithelium

Back 80

organ of smell located in the roof of the nasal cavity

Hint 80

Front 81

olfactory sensory neurons

Back 81

bowling pin-shaped receptor cells of the olfactory epithelium

Hint 81

Front 82

supporting cells

Back 82

cells surrounding and cushioning the olfactory sensory neurons

Hint 82

Front 83

olfactory cilia

Back 83

increase the receptive surface area of olfactory sensory neurons

Hint 83

Front 84

specificity

Back 84

the process of 400 "smell genes" creating combinations for 10,000+ different odors

Front 85

- olfactory nerve (CN I)

- olfactory bulb

- olfactory tract

- olfactory cortex

Back 85

trace the path of smell as it enters the nose (4)

Front 86

taste buds

Back 86

sensory organs for taste located on the tongue

Hint 86

Front 87

papillae

Back 87

peglike projections of the tongue mucosa that make the tongue surface slightly abrasive; house taste buds

Hint 87

Front 88

1. fungiform

2. foliate

3. vallate

Back 88

3 types of papillae

Hint 88

Front 89

1. gustatory epithelial cells

2. basal epithelial cells

Back 89

2 cell types found in taste buds

Hint 89

Front 90

gustatory epithelial cells

Back 90

receptor cells for taste; taste cells

Hint 90

Front 91

gustatory hairs

Back 91

long microvilli that project from the tips of gustatory epithelial cells; sensitive portion of the cell

Hint 91

Front 92

basal epithelial cells

Back 92

stem cells that become new gustatory epithelial cells

Hint 92

Front 93

1. sweet

2. sour

3. salty

4. bitter

5. umami

Back 93

5 basic taste sensations

Front 94

sweet

Back 94

taste sensation elicited by sugars and some amino acids

Front 95

sour

Back 95

taste sensation elicited by acids (hydrogen ions)

Front 96

salty

Back 96

taste sensation elicited by sodium

Front 97

bitter

Back 97

taste sensation elicited by alkaloids or rotten foods

Front 98

saliva

Back 98

must dissolve chemicals before they can be tasted

Front 99

1. facial nerve (CN VII)

2. glossopharyngeal (CN IX)

Back 99

2 main cranial nerves that carry taste information

Hint 99

Front 100

1. external ear

2. middle ear

3. internal ear

Back 100

3 main areas of the ear

Front 101

1. auricle (pinna)

2. external acoustic meatus (auditory canal)

3. tympanic membrane (eardrum)

Back 101

3 main parts of the external ear (outer ear)

Front 102

auricle (pinna)

Back 102

elastic cartilage surrounding the opening of the external acoustic meatus (auditory canal)

Front 103

external acoustic meatus (auditory canal)

Back 103

a short, curved tube that extends from the auricle to the eardrum; contains hairs, sebaceous glands, and ceruminous glands

Front 104

tympanic membrane (eardrum)

Back 104

thin, translucent connective tissue membrane between the outer and middle ears

Front 105

1. ossicles

2. oval window

3. pharyngotympanic tube (auditory tube)

Back 105

3 main parts of the middle ear (tympanic cavity)

Front 106

ossicles

Back 106

send vibration from the tympanic membrane to the oval window; three smallest bones in the body

Front 107

malleus

Back 107

the ossicle secured to the tympanic membrane (eardrum)

Front 108

incus

Back 108

middle ossicle

Front 109

stapes

Back 109

ossicle that fits into the oval window

Front 110

oval window

Back 110

opening in the lateral wall of the inner ear that eventually leads to the cochlea

Front 111

pharyngotympanic tube (auditory/eustachian tube)

Back 111

equalizes pressure in the middle ear with external air pressure; runs from the middle ear to the nasopharynx

Front 112

1. cochlea

2. vestibule

3. semicircular canals

Back 112

3 main parts of the inner ear (labyrinth)

Front 113

cochlea

Back 113

spiral bone cavity filled with endolymph

Front 114

endolymph

Back 114

fluid that conducts sound vibrations

Front 115

organ of Corti (spiral organ)

Back 115

receptor organ for hearing, located in the cochlea duct

Front 116

vestibule

Back 116

egg-shaped cavity between the cochlea and the semicircular ducts

Front 117

semicircular canals

Back 117

set of three canals (anterior, posterior, lateral) that attach to the vestibule of the inner ear

Front 118

crista ampullaris

Back 118

equilibrium receptors at the base of the semicircular canals that respond to rotational movement of the head

Front 119

sound

Back 119

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

Front 120

frequency

Back 120

the number of sound waves that pass a given point in a given time; measured in Hz (hertz)

Front 121

amplitude

Back 121

height of the sound wave, representing the intensity of the sound; measured in dB (decibels)

Front 122

differential stimulation

Back 122

the process of different pitches stimulating different areas of hair cells

Front 123

amplification

Back 123

pressure hitting the oval window is 20x greater than on the eardrum, due to its smaller size

Front 124

cochlear hair cells

Back 124

cilia that protrude into the endolymph and are vibrated; open K+ channels

Front 125

cochlear nerve

Back 125

nerve serving the auditory pathway; leads to the inferior colliculi (of the midbrain) and the thalamus, before being routed to the temporal lobe

Front 126

conduction deafness

Back 126

deafness caused by interference with conduction of vibrations to the inner ear, due to blockage of the external ear or ossicles fusing together

Front 127

sensorineural deafness

Back 127

deafness caused by damage to the hair cells (loud noises) or neural component problem (hair cells to cortex)

Front 128

static equilibrium

Back 128

linear changes in head position

Front 129

dynamic equilibrium

Back 129

rotational acceleration changes in head position

Front 130

maculae

Back 130

equilibrium receptors of the inner ear that respond to change in position of the head

Front 131

1. vestibular nuclei

2. cerebellum

Back 131

2 destinations of the equilibrium pathway

Front 132

motion sickness

Back 132

sickness caused by a mismatch of vision and equilibrium signals; nausea and vomiting