Chapter2 Flashcards
(212 cards)
1
Q
What do sense organs do?
A
Transform stimuli into perceptions
2
Q
What is the process by which stimuli are converted to electrical signals?
A
Transduction
3
Q
What do we perceive through our sense organs?
A
Energy and molecules
4
Q
What percentage of the cerebral cortex is involved in the visual system?
A
30 percent
5
Q
What is the primary function of vision?
A
Perceiving surroundings
6
Q
How does the brain process visual messages?
A
Through specialized areas
7
Q
What has been studied intensively related to sensory systems?
A
Vision
8
Q
Which organisms have primarily contributed to knowledge of light energy conversion?
A
Fruit flies and mice
9
Q
In what animals has higher-level visual processing been studied?
A
Monkeys and cats
10
Q
How can seeing with your eyes be compared?
A
Like taking pictures
11
Q
What regulates light entry into the eye?
A
Iris
12
Q
What structure allows light to enter the eye?
A
Pupil
13
Q
What structure focuses light onto the retina?
A
Lens
14
Q
What does the cornea do?
A
Initial focusing
15
Q
What is the surface where light is focused called?
A
Retina
16
Q
How does the lens adjust focus?
A
Thickens or flattens
17
Q
How is visual input mapped on the retina?
A
Two-dimensional reversed image
18
Q
Where do objects to the right project images?
A
Left side of retina
19
Q
Where are photoreceptors located in the retina?
A
Peripheral layer
20
Q
What do ganglion cells and interneurons do?
A
Process and relay information
21
Q
What forms the optic nerve?
A
Axons of ganglion cells
22
Q
What is the purpose of photoreceptors?
A
Convert light to signals
23
Q
What is the process of converting energy known as?
A
Transduction
24
Q
What percentage of photoreceptors are rods in humans?
A
95 percent
25
What do rods allow you to see in?
Dim light
26
What do cones detect?
Detail and color
27
What types of cones are in the human eye?
Red, green, blue
28
How do cones convey color information?
Differing combinations
29
Where is vision sharper in the retina?
Center of retina
30
What is the fovea?
Small area with dense cones
31
What types of cones are in the fovea?
Red and green cones
32
What is the function of the macula?
Critical for reading and driving
33
What is macular degeneration?
Death of photoreceptors in macula
34
What is a leading cause of blindness in those over 55?
Macular degeneration
35
What is the input pattern for ganglion cells in the macular region?
Few cones
36
What allows for high visual acuity in the macular region?
Fine details resolution
37
How do inputs to ganglion cells differ near the margins of the retina?
Many photoreceptors
38
What is less detailed in vision?
Peripheral vision
39
What is the area providing input to a single ganglion cell?
Receptive field
40
What do axons extend through to reach the brain?
Optic nerve
41
What type of cells provide nutritional support to the retina?
Astrocytes
42
What begins visual processing?
Comparing light amounts
43
What do the receptive fields of ganglion cells provide?
Complete 2D representation
44
What activates a ganglion cell's receptive field?
Light hits center region
45
What inhibits a ganglion cell's receptive field?
Light hits surrounding area
46
What happens when light strikes the entire receptive field?
Weak response
47
What is the first way the visual system maximizes perception of contrast?
Center-surround antagonism
48
How is neural activity from ganglion cells transmitted?
Via optic nerves
49
What results from the exit point of the optic nerve?
Blind spot
50
How does the brain deal with the blind spot?
Fills in information
51
What is the optic chiasm?
Crossover junction
52
Where do the signals from the left side of the retinas go?
Left side of the brain
53
Where do the signals from the right side of the retinas go?
Right side of the brain
54
Cells in the primary visual cortex are arranged in layers.
True
55
Cells in the middle layer of the primary visual cortex have receptive fields similar to those in the retina.
True
56
Cells above and below the middle layer of the primary visual cortex have more complex receptive fields.
True
57
Some cells in the primary visual cortex can respond to edges at a certain angle.
True
58
Some cells in the primary visual cortex can respond to moving stimuli.
True
59
New processing streams pass information from the primary visual cortex to other parts of the visual cortex.
True
60
What happens to receptive fields as visual information is combined?
Becomes complex and selective
61
What types of stimuli do some neurons at higher processing levels respond to?
Specific objects and faces
62
What are the two main visual processing streams?
Dorsal and ventral
63
Which lobe does the dorsal stream go toward?
Parietal lobe
64
Which lobe does the ventral stream go toward?
Temporal lobe
65
What does the ventral stream process?
Shape and color recognition
66
What does the dorsal stream process?
Spatial relationships and motion
67
What is the purpose of the dorsal stream?
Create action plan
68
What does ongoing research suggest about the division of labor in the brain?
Crosstalk may create experience.
69
What is binocular vision?
Seeing with two eyes.
70
What does binocular vision allow you to perceive?
Depth or three dimensions.
71
What condition causes reduced depth perception?
Strabismus
72
Where is information from both eyes processed?
Primary visual cortex
73
What is the benefit of having two eyes?
Larger visual field
74
What happens at the optic chiasm?
Nerve fibers cross over
75
Which side of the brain processes signals from the left visual field?
Right side
76
Which half of the cerebrum processes information from the opposite body side?
Each half
77
What have animal studies provided insights into?
Treating visual disorders
78
What animal research has aided strabismus therapies?
Cats and monkeys
79
What happens to children with strabismus?
Favor one eye
80
When does blindness from strabismus become permanent?
Age 8
81
What was the previous age for surgery on children with strabismus?
Age 4
82
When is strabismus best corrected?
Before age 4
83
What lies at the heart of disorders causing blindness?
Photoreceptor loss
84
What can gene or stem cell therapies help recover?
Photoreceptors
85
What have gene therapies enabled for patients with macular degeneration?
See better
86
What new approach is being explored for genetic blindness?
Send signals to brain
87
How is the new approach for blindness similar to deafness treatment?
Cochlear implants
88
What is the importance of hearing?
Alerts to danger, aids communication
89
What qualities does the auditory system detect?
Pitch, loudness, duration, location
90
How does hearing impact social interactions?
Facilitates communication
91
What does the auditory system analyze?
Complex sounds
92
What can you follow in a conversation or music?
Particular voices or instruments
93
What is required for hearing?
Conversion of sound waves
94
How are sound waves carried to the brain?
Electrical signals by nerve cells
95
How does sound reach the eardrum?
Air pressure waves funnel into ear canals
96
What are the three tiny bones in the middle ear?
Malleus, Incus, Stapes
97
What does the stapes do?
Acts like a tiny piston
98
What separates the middle ear from the cochlea?
Oval window
99
What does the oval window convert?
Mechanical vibrations
100
What are the pressure waves transduced into?
Electrical signals
101
What runs along the inside of the cochlea?
Basilar membrane
102
How do different frequencies affect the cochlea?
Higher pitches near oval window, lower in center
103
What happens when the basilar membrane moves?
Hair cells bend against tectorial membrane
104
What opens channels in stereocilia?
Bending
105
What do hair cells excite?
Auditory nerve
106
What is the brain's relay station for sensory information?
Thalamus
107
Where does sound processing go after the thalamus?
Cerebral cortex
108
What are hair cells responsive to?
Narrow range of sound frequencies
109
Where are hair cells located?
Along the basilar membrane
110
What do nerve fibers connected to hair cells carry?
Information on specific frequencies
111
How is sound direction computed?
Brainstem and thalamus
112
What maintains the frequency map?
Basilar membrane
113
Where do different auditory neurons respond to frequencies?
Primary auditory cortex
114
What do some cortical neurons respond to?
Intensity, duration, frequency change
115
What do other neurons specialize in?
Complex sounds, combinations of tones
116
What do smell and taste perceive?
Tiny molecules
117
Why are smell and taste important to survival?
Detect hazardous substances
118
What can harm taste and smell cells?
Outside environment
119
What kind of cells regularly regenerate?
Taste receptor cells
120
Which sensory neurons are continually replaced?
Olfactory neurons
121
How do we taste food?
Detected molecules
122
Where are taste buds located?
Tongue and mouth
123
How many taste buds do we have?
5,000 to 10,000
124
At what age do we start losing taste buds?
Around age 50
125
How many sensory cells does each taste bud consist of?
50 to 100
126
What are the five basic taste qualities?
Sweet, sour, salty, bitter, umami
127
What cranial nerves are involved in taste?
Facial, glossopharyngeal, vagus
128
Where do taste impulses route through?
Thalamus to gustatory cortex
129
What part of the brain identifies taste perceptions?
Frontal lobe and insula
130
How do odors enter the nose?
Air currents
131
What do odors bind to in the nasal cavity?
Olfactory cells
132
What enters the olfactory bulbs?
Sensory neuron axons
133
Where does smell information go first?
Olfactory cortex
134
What is unique about the smell sensory system?
Bypasses thalamus
135
How many types of olfactory cells do we have?
Around 1,000
136
How many smells can we identify?
About 20 times more
137
What do olfactory cells have that helps them detect odors?
Hair-like cilia
138
What creates a distinct activity pattern in the olfactory system?
Unique smell stimulation
139
Where is the primary olfactory cortex located?
Temporal lobe
140
How quickly can people identify odors?
110 milliseconds
141
What can change over time in relation to the olfactory bulbs?
Size and neuron organization
142
What is unique about the olfactory bulbs in rodents and primates?
Neurogenesis throughout life
143
What happens to taste when the nose is stuffed up?
Food tastes bland
144
How does smell influence taste perception?
Enhances flavor complexity
145
What enhances taste perceptions?
Matching tastes and smells
146
How does sugar taste with strawberry smell?
Sweeter
147
Where do taste and smell information converge?
Central regions of the brain
148
What do taste buds do?
Transform taste information
149
What connects taste receptors to the brain?
Axons
150
What do hair cells in the cochlea convert?
Vibrations to electrical signals
151
How are signals sent to the brain?
Via cochlear nerve
152
What happens to taste and smell sensitivity as we age?
Sensitivity decreases
153
What causes the loss of taste and smell sensitivity?
Damaged receptors
154
What is current research focused on regarding taste and smell?
Stem cells and neurons
155
What potential future application is mentioned for stem cell research?
Restore taste or smell
156
What system is responsible for touch sensations?
Somatosensory system
157
What types of sensations does the somatosensory system include?
Touch, pressure, pain, etc.
158
Where are the nerve endings for touch receptors located?
Different skin layers
159
What type of skin has sensitive nerve endings around hair bases?
Hairy skin
160
How do touch signals travel?
Sensory fibers to spinal cord
161
Where are touch signals translated?
Somatosensory cortex
162
What are A-beta fibers?
Thick myelinated axons
163
What are C fibers?
Thin unmyelinated axons
164
What forms a topographic map on the cortex?
Somatosensory information
165
Which body areas are most sensitive to touch?
Lips and fingertips
166
What affects sensitivity to touch and pain?
Receptors per unit area
167
Why is the back less sensitive than the hands?
Few, far apart receptors
168
What is two-point discrimination?
Identifies distinct stimuli.
169
Where is acuity greatest?
Densely nerve-packed areas.
170
What is the two-point threshold?
Lowest in densely nerve-packed areas.
171
What are nociceptors?
Special sensory fibers
172
What does pain signal?
Tissue damage
173
What are the components of pain?
Sensory and emotional
174
What is the primary function of pain?
Warning signal
175
What do nociceptors normally respond to?
High-threshold stimuli
176
What types of painful stimuli are nociceptors sensitive to?
Thermal, mechanical, chemical
177
What can trigger a burning pain in nociceptors?
Capsaicin in spicy food
178
What stimulates itch-specific nociceptors?
Chemical stimuli
179
What activates histamine receptors?
Skin irritation
180
What is released at the site of tissue injury?
Various chemicals
181
What does tissue injury cause?
Inflammation
182
What do prostaglandins do?
Enhance pain sensitivity
183
What condition can peaks of pain sensitivity lead to?
Allodynia
184
What can a long-lasting injury cause?
Nervous system changes
185
What is neuropathic pain?
Hypersensitivity to pain
186
What causes diabetic neuropathy?
High blood sugar
187
What symptoms are associated with diabetic neuropathy?
Numbness, tingling, burning, aching
188
What fibers transmit pain and itch messages?
A-delta and C fibers
189
What do A-delta fibers evoke?
Sharp pain
190
How do C fibers transmit pain?
More slowly
191
What kind of pain do C fibers produce?
Dull and diffuse
192
Where do pain and itch signals travel to?
Thalamus
193
What happens to pain and itch messages in the brain?
Transformed into conscious experience
194
What factors affect pain experience?
Strength of stimulus, emotional state, setting
195
What does the cortex do when pain messages arrive?
Processes them in different ways
196
Which region does the cortex send pain messages to?
Periaqueductal gray matter
197
What does the periaqueductal gray matter activate?
Descending pathways that modulate pain
198
What substances do the pathways release?
Endorphins
199
What do endorphins act like?
Analgesic morphine
200
What is adrenaline's role in stressful situations?
Analgesic effect
201
How does the body regulate pain?
Intercepts pain signals
202
What influences how much pain a person feels?
Efficacy and sensitivity of brain circuits
203
Why do some people develop chronic pain?
Does not respond to treatment
204
What do endorphins act on in the brain and spinal cord?
Opioid receptors
205
What is the implication of opioid drugs for surgery?
Pain reduction
206
What are scientists studying to relieve pain?
Electrical stimulation of spinal cord
207
What influences pain perception?
Emotional and sensory components
208
Which methods target the emotional component of pain?
Meditation, hypnosis, etc.
209
Is there a single brain area for pain perception?
No single area responsible
210
How does cannabis affect pain perception in the brain?
Suppresses activity in pain areas
211
Which brain area is primarily affected by cannabis for pain?
Limbic system
212
What do the sensory nerve fibers in the mouse embryo detect?
Pressure, pain, temperature, itch
