Ch. 17 The Special Senses Flashcards
(131 cards)
1
Q
Where are the receptors for the special senses?
A
In complex sensory organs
2
Q
Ophthalmology
A
The science that deals with the eye and its disorders
3
Q
Otolaryngology
A
The science that deals with the other special senses
4
Q
Olfaction
A
Sense of smell
5
Q
Both smell and taste are…
A
Chemical senses
6
Q
What are the receptors for olfaction?
A
Bipolar neurons
7
Q
Where are the receptors for olfaction?
A
In the nasal epithelium in the superior portion of the nasal cavity
8
Q
What are the supporting cells of olfaction?
A
Epithelial cells of the mucous membrane lining the nose
9
Q
What produces new olfactory receptors?
A
Basal stem cells
10
Q
How many primary scents are there?
A
Hundreds
11
Q
In olfactory reception, what does a generator potential do?
A
Develops and triggers one or more nerve impulses
12
Q
Adaptation to odors occurs…?
A
Quickly
13
Q
True or false: only a few molecules of certain substances need to be present in the air to be smelled.
A
True
14
Q
Olfactory receptors convey nerve impulses to..?
A
Olfactory nerves, olfactory bulbs, olfactory tracts, and the cerebral cortex and limbic system
15
Q
Hyposmia
A
-a reduced ability to smell
-affects half of those over age 65, 75% of those over 80
-can be caused by neurological changes, drugs, or the effects of smoking
16
Q
Gustatory
A
Sense of smell
17
Q
How must taste be detected?
A
The molecules have to be dissolved
18
Q
Taste stimuli classes include:
A
Sour, sweet, bitter,and salty
19
Q
How are other tastes defected?
A
A combination of the four taste sensations plus olfaction
20
Q
The receptors for gustation
A
Gustatory receptor cells
21
Q
Where are gustatory receptor cells located?
A
In taste buds
22
Q
What do taste buds consist of?
A
Supporting cells, gustatory receptor cells, and basal cells
23
Q
Where are taste buds found?
A
In the papillae
24
Q
The papillae include:
A
Circumvallate, fungiform,and filiform papillae
25
What happens when a tastant is dissolved in saliva?
it can make contact with the plasma membrane of gustatory receptors
26
What do receptor potentials developed in gustatory hairs cause?
the release of neurotransmitter that gives rise to nerve impulses
27
True or false: individual gustatory receptors in certain regions of the tongue are more sensitive than others to the primary taste sensations
true
28
List the taste thresholds for each of the primary tastes from lowest to highest
bitter, sour, salty, then sweet
29
Where do gustatory receptor cells convey nerve impulses?
-cranial nerves V, VII, IX, and S
-medulla
-thalamus
-and the parietal lobe of the cerebral cortex
30
Taste aversion
causes individuals to avoid foods that upset their digestive system
-common in cancer patients
31
Where are more than half the sensory receptors in the human body located?
in the eyes
32
What is a large part of the cerebral cortex devoted to?
processing visual information
33
Functions of the eyelids
-shade the eyes during sleep
-protect the eyes from excessive light and foreign objects
-spread lubricating secretions over the eyeballs
34
From superficial to deep, list the layers of the eyelid
epidermis
dermis
subcutaneous tissue
fibers of the orbicularis oculi muscle
a tarsal plate
tarsal glands
conjunctiva
35
Tarsal plate
gives form and support to the eyelids
36
Tarsal glands
secrete a fluid to keep the eyelids from adhering to each other
37
Conjunctiva
a thin mucous membrane that lines the inner aspect of the eyelids and is reflected onto the anterior surface of the eyeball
38
Function of the eyelashes and eyebrows
help protect the eyeballs from foreign objects, perspiration, and the direct rays of the sun
39
Lacrimal apparatus
consists of structures that produce and drain tears
40
How do the six extrinsic eye muscles move the eyeballs?
laterally, medially, superiorly, and inferiorly
41
How many layers does the eye have?
3
42
Fibrous tunic
-outer coat of the eyeball
can be divided into 2 regions: posterior sclera and anterior cornea
43
The opening at the junction of the sclera and cornea
the scleral venous sinus or canal of Schlemm
44
Sclera
The white coat of dense fibrous tissue that covers the entire eyeball, except the most anterior portion, the iris
-gives shape to the eyeball and protects its inner parts
-pierced posteriorly by the optic nerve
45
Cornea
a nonvascular, transparent, fibrous coat through which the iris can be seen; the cornea acts in refraction of light
46
LASIK
a refractive surgery that corrects the curvature of the cornea for conditions such as farsightedness, nearsightedness, and astigmatism
47
Vascular tunic
the middle layer of the eyeball that is composed of three portions: choroid, ciliary body, and iris
48
Choroid
absorbs light rays so that they are not reflected and scattered within the eyeball
-provides nutrients to the posterior surface of the retina
49
Ciliary body
consists of the ciliary processes and ciliary muscle
50
Ciliary processes
consist of protrusions or folds on the internal surface of the ciliary body where epithelial lining cells secrete aqueous humor
51
Ciliary muscle
a smooth muscle that alters the shape of the lens for near or far vision
52
Iris
the colored portion is seen through the cornea and consists of a circular iris and radial iris smooth muscle fibers arranged to form a donut-shaped structure
53
Pupil
the black hole in the center of the iris through which light enters the eyeball
54
Principal function of the iris
to regulate the amount of light entering the posterior cavity of the eyeball
55
Retina
the third and inner coat of the eye that lines the posterior 3/4 of the eyeball and is the beginning of the visual pathway
56
Where is the only place in the body where blood vessels can be viewed directly and examined for pathological changes?
the surface of the retina
57
Optic Disc
the site where the optic nerve enters the eyeball
58
What are the vessels of the retina?
the central retinal artery and vein
59
Visual and nonvisual portions of the retina
-pigment epithelium (nonvisual)
-neural portion (visual)
60
What aids the choroid in absorbing stray light rays?
the pigment epithelium
61
Three zones of neurons in the neural portion of retina
photoreceptor neurons, bipolar neurons, and ganglion neurons (named in the order in which they conduct nerve impulses)
62
Why are photoreceptor neurons called rods or cones?
because of the differing shapes of their outer segments
63
Rods
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
64
Cones
specialized for color vision and sharpness of vision in bright light
65
Macula lutea
in the exact center of the posterior portion of the retina, corresponding to the visual axis of the eye
66
Fovea
the area of sharpest vision because of the high concentration of cones
67
Where are rods absent?
from the fovea and macula
68
Nonvascular lens
behind the pupil and iris
69
The lens
fine-tunes the focusing of light rays for clear vision
70
Presbyopia
with aging, the lens loses elasticity and its ability to accommodate
71
Two cavities by the lens at the interior of the eyeball
anterior cavity and the vitreous chamber
72
Subdivisions of the anterior cavity
the anterior chamber and the posterior chamber
73
Aqueous humor
in the anterior cavity, continually secreted by the ciliary processes behind the iris
74
Aqueous humor flow
from the posterior chamber through the pupil into the anterior chamber and drains into the scleral venous sinus and then into the blood
75
Intraocular pressure
-produced by aqueous humor
maintains the shape of the eyeball and keeps the retina smoothly applied to the choroid so the retina will form clear images
76
Glaucoma
excessive intraocular pressure that results in degeneration of the retina and blindness
77
Vitreous chamber
lies between the lens and the retina and contains a gel called, vitreous body
78
Age-related macular disease
a degenerative disorder of the retina and the pigmented layer in persons 50 years or older
79
Image formation on the retina
involves refraction of light rays by the cornea and lens, and constriction of the pupil
80
Refraction
the bending of light rays at the interface of two different media
81
How are images focused on the retina?
upside-down (inverted)
82
Accommodation
is an increase in the curvature of the lens, initiated by ciliary muscle contraction, which allows the lens to focus on near objects
83
Near point of vision
the minimum distance from the eye that an object can be clearly focused with maximum effort
84
Myopia
nearsightedness
85
Hyperopia
farsightedness
86
Astigmatism
a refraction abnormality due to an irregular curvature of either the cornea or lens
87
Convergence
the eyeballs move medially so they are both directed toward an object being viewed
88
What is the first step in vision transduction?
the absorption of light by photopigments
89
Photopigments
colored proteins that undergo structural changes upon light absorption
90
What is the type of photopigment in rods
rhodopsin
91
What do all photopigments involved in vision contain?
a glycoprotein called opsin and a derivative of vitamin A called retinal
92
What is the light absorbing part of all visual photopigments?
retinal
93
What happens once receptor potentials develop in rods and cones?
they release neurotransmitters that induce graded potentials in bipolar cells and horizontal cells
94
What do most forms of colorblindness result from?
an inherited absence of or deficiency in one of the three cone photopigments
95
Horizontal cells
transmit inhibitory signals to bipolar cells
96
Impulses from ganglion cells are conveyed through the retina to the...
optic nerve, the optic chiasma, the optic tract, the thalamus, and the occipital lobes of the cortex
97
Three anatomical subdivisions of the ear
external (outer) ear, middle ear (tympanic cavity), and internal (inner) ear
98
External (outer) ear
collects sound waves and passes them inwards
99
What does the external (outer) ear consist of?
-auricle (pinna)
-external auditory canal (meatus)
-tympanic membrane (eardrum)
100
Ceruminous glands
secrete cerumen (earwax) to help prevent dust and foreign objects from entering the ear
101
Middle ear (tympanic cavity)
a small, air-filled cavity in the temporal bone that is lined by epithelium
102
What does the middle ear (tympanic cavity) consist of?
auditory (eustachian) tube, auditory ossicles (middle ear bones, the malleus, incus, and stapes), oval window, and the round window
103
The internal (inner) ear
also called the labyrinth because of its complicated series of canals
104
Two main divisions of the internal (inner) ear
the outer bony labyrinth that encloses an inner membranous labyrinth
105
Bony labyrinth
a series of cavities in the petrous portion of the temporal bone
106
Three areas of the bony labyrinth
-semicircular canals and vestibule: containing receptors for equilibrium
-the cochlea: containing receptors for hearing
107
What is the bony labyrinth lined with?
periosteum
108
Fluid in the bony labyrinth
perilymph
109
Perilymph
chemically similar to CSF, surrounds the membranous labyrinth
110
Membranous labyrinth
a series of sacs and tubes lying inside and having the same general form as the bony labyrinth
111
The vestibular branch of the vestibulocochlear nerve consists of?
ampullary, utricular, and saccular nerves
112
Cochlea
consists of a bony spiral canal that makes three turns around a central bony core called the modiolus
113
Three channels of the cochlea
-scala vestibuli
-scala tympani
-the cochlear duct (scala media)
114
Sound waves most acutely by human ears are from sources that vibrate at frequencies between...
1000 and 4000 Hertz
115
Pitch
the frequency of a sound wave
116
Events involved in hearing
1. auricle directs sound waves into the external auditory canal
2. sound waves strike the tympanic membrane, causing it to vibrate
3. vibration conducts from the tympanic membrane through the ossicles (malleus to the incus to the stapes)
4. stapes move back and forth, pushing the membrane of the oval window in and out
5. movement of the oval window sets up fluid pressure waves in the perilymph of the cochlea
6. pressure waves in scala vestibuli transmit to scala tympani and the round window, bulging to the middle ear
7. pressure deforms the scala vestibuli and scala tympani, they both push vestibular membrane back and forth and changes the pressure of endolymph in cochlear duct
8. pressure fluctuations move the basilar membrane, bending hair cells and producing receptor potentials that lead to nerve impulses in cochlear nerve fibers
9. pressure changes in scala tympani cause round window to bulge outward into the middle ear
117
High-frequency or high-pitched sounds
cause the basilar membrane to vibrate near the base of the cochlea
118
Low-frequency or low-pitched sounds
cause the basilar membrane to vibrate near the apex of the cochlea
119
Otosclerosis
a condition where there is an overgrowth of spongy bone over the oval window that immobilizes the stapes, preventing the transmission of soundwaves to the inner ear and leads to hearing loss
120
Auditory Pathway
nerve impulses from the cochlear branch of the vestibulocochlear nerve pass to the cochlear nuclei in the medulla. Most impulses cross to the opposite side then travel to the midbrain, thalamus, and auditory area of temporal lobe
121
Cochlear implants
devices that translate sounds into electronic signals that can be interpreted by the brain
122
Static equilibrium
the maintenance of the position of the body relative to the force of gravity
123
Dynamic equilibrium
the maintenance of body position in response to sudden movements, such as rotation, acceleration, and deceleration.
124
Age related changes in the eyes
presbyopia and cataracts
125
Presbycusis
hearing loss due to damaged or loss of hair cells in the organ of Corti
126
Tinnitus
ringing in the ears
127
Cataract
loss of transparency of the lens that can lead to blindness
128
Glaucoma
abnormally high intraocular pressure, due to a buildup of aqueous humor inside the eyeball, destroying neurons of the retina
129
Deafness
a significant or total hearing loss
130
Meniere's syndrome
a malfunction of the inner ear that may cause deafness and loss of equilibrium
131
Otitis media
an acute infection of the middle ear, primarily by bacteria. Characterized by pain, malaise, fever, reddening of the eardrum
