Exam 2 Flashcards
1
Q
what are the characteristics of a light energy wave?
A
wavelength: color or shades of gray
amplitude: brightness
2
Q
reflection
A
the bending of light back towards it’s source; accounts for most light we see
3
Q
absorption
A
object retains light; cannot be seen but can be felt
4
Q
refraction
A
the changing of light at a boundary such as that between air and water; responsible for forming images in the eye
5
Q
optical functions
A
capture light and form detailed spatial images
6
Q
protective functions
A
eyelid protects and cleans tears produced from lacrimal gland
7
Q
neural functions
A
transduce light into neural signals, then relay and process those signals
8
Q
fovea
A
high visual acuity found in the retina
9
Q
what is a blind spot?
A
where topic n. and blood vessels exit the retina there are no photoreceptors and no vision
10
Q
what cell populations are found in the retina?
A
photoreceptors- rods and cones
11
Q
rods
A
scotopic vision- dim light
no color, low acuity
120 million in humans
12
Q
cones
A
photopic vision- bright light
color, high acuity
6 million in humans
13
Q
photopigment
A
outer segment of photoreceptors filled with light-sensative chemicals
14
Q
what is the photopigment in rods?
A
rhodopsin: composed of opsin & retinal
retinal is the light absorbent
15
Q
what is the photoreceptor in cones?
A
iodopsin
16
Q
transduction
A
translation of physical stimulus into electrical signals used by the nervous system
17
Q
the dark current
A
the steady depolarization maintained by photoreceptors when NO light is present
18
Q
steps involved in signal transduction (in the dark)
A
- rhodopsin consists of opsin and retinal
- retinal is in 11-cis form
- photoreceptor cell produces cGMP
- cGMP causes sodium channels to open
- photoreceptor cell is DEPOLARIZED
- outcome = increased release of glutamate
19
Q
steps involved in signal transduction (in the light)
A
- retinal absorbs a photon
- retinal changes to all-trans form and rhodopsin molecule breaks apart
- enzymes are released, which break down cGMP
- in the absence of cGMP, sodium channels close
- photoreceptor becomes HYPERPOLARIZED, the more light absorbed, the more hyperpolarized
- outcome = decreased release of glutamate
20
Q
what cell is involved in transmitting light information from the retina?
A
bipolar cells?
21
Q
receptive field
A
a location on the retina at which light affects the activity of a particular visual interneuron
22
Q
types of receptive fields on the retina?
A
center: direct input from single set of photoreceptors
surround: indirect from horizontal cells connected to photoreceptors
23
Q
what type of potentials do bipolar cells use?
A
graded potentials
24
Q
what type of potentials do ganglion cells use?
A
action potentials
25
on-center light restricted to center
depolarizes bipolar cell
26
on- center light restricted to surround
relayed through horizontal cells; hyperpolarizes bipolar cell
27
off-center light restricted to center
hyerpolarizes bipolar cell
28
off-center light restricted to surround
relayed through horizontal cells; depolarizes bipolar cells
29
3 types of ganglion cells
```
M cells (magno; large)
P cells (parvo; small)
K cells (koniocellular)
```
30
M cells
motion: large, low-contrast moving objects
31
P cells
color sensitive: small, high-contrast color objects
32
K cells
color sensitive
33
optic nerve
anterior portion, connects directly to eye
34
optic chiasma
area at the base of the brain where the optic nerves cross to form the optic tracts
35
optic tract
the fiber pathways between the optic chiasma and destinations in the forebrain and brainstem
- about 50% of fibers cross to opposite hemisphere
36
visual fields
projections from the right and left hemispheres
37
superior colliculus
- located in the midbrain
- guides head and eye movements
- 10% of optic tract
38
lateral geniculate nucleus (LGN)
- located in thalamus
- projects to primary visual cortex
- visual perception
- 90% of optic tract
39
three layers of LGN
magnocellular
parvocellular
koinocellular
40
magnocelluar layer
input: M cells layers 1&2
41
parvocellular layer
input: P cells layers 3-6
42
koinocellular layer
input: K cells
43
simple receptive fields
- receptive fields maintain antagonistic center surround
- shape of receptive field elongated
- respond to stimuli that have a particular slant or orientation
- retinotopic mapping
44
complex cortical cell
- larger receptive fields
- no off region
- shows preferred stimulus size and orientation but not location within visual field
- sensitive to movement
- perception of movement
- retinotopic mapping
45
orientation column
responds to lines of a single angle for a single eye
46
ocular dominance column
responds to input from either the left or right eye but NOT both. preferred orientation changes.
47
simple cortical cells
orientation
48
complex cortical cells
movement
49
cortical module
- integration of decomposed visual field
- 1000 modules, each 2X2 mm
- 8-10% of all modules devoted to input from fovea
50
"where" pathway
- dorsal pathway
- magnocellular projection
- specialized for: movement, locating objects, and visual control of skilled actions
51
"what" pathway
- ventral pathway
- parvocellular projection
- responds to object recognition, shapes, and color
- associated with storage of long-term memory
52
fusiform facial area
- part of the ventral stream
- located within fusiform gyrus of inferior temporal lobe
- responds predominantly to faces and members of learned categories
53
prosopagonosia
facial blindness where you can see all components of the face but cannot recognize that face specifically
- injury or congenital
- 1-3% of population
54
sensation
information from environment and its transmission to the CNS
55
perception
personalized interpretation of sensory data
56
akinetopsia
- motion blindness
- damage at the occipital-parietal junction
- extremely rare
57
how is depth processed in the visual system?
stereopsis: depth from 2D image
58
monocular
perspective and depth seen through one eye
59
binocular
- retinal disparity using BOTH eyes
- slightly different views of the visual field provided by the two eyes
- increases with the distance of objects from the viewer
60
trichromatic theory of color?
also known as the young-helmholtz theory
| eye responds to 3 primary colors, allowing them to mix to see other colors
61
opponent process theory?
k cells: blue- yellow
p cells: red- green
- p cells are primary in ganglion cells so they can see colored light and the cones respond accordingly
- k cells take the output of short blue cones then take the sum of red and blue cones inout together to get the yellow (since there is no yellow cone)
62
what causes color blindness? what cones are affected?
cause: sex linked OR missing chromosome 7, can be dichromacy or monochromacy
- monochromacy: one or no cones are affected and everything is in a green filter
cones affected: deficits in red or green photopigment OR missing blue photopigment
63
color contrast
color can appear different based on its "context" or background
64
color constancy
colors perceived as the same, although they are different
65
hierarchical processing
visual world is decomposed then built back up from the simple to complex
66
feature detectors
aka grandmother cell; responds to particular features, angles, lines, movement, etc
67
frequency in terms of waves
the cycle per unit time or wavelength of sound
68
loudness
aka intensity; a function of sound wave amplitude
69
what are the major structures of the ear?
```
ear canal
pinna
eardrum
semicircular canal
vestibular nerve
auditory nerve
cochlear nerve
cochlea
eustachian tube
vestibule
```
70
ossicles
transfer sound from air to fluid
- malleus (hammer)
- incus (anvil)
- stapes (stirrup)
71
cochlea responds to...
vibrations from the middle ear
72
liquid pressure in the inner ear is initiated where?
the oval window
73
liquid pressure in the inner ear is relieved where?
the round window
74
what are the 3 chambers of the inner ear?
vestibular canal
cohlear duct
tympanic canal
75
endolymph
high K+ and low Na+
76
where are hair cells?
organ of corti
77
how are hair cells activated?
vibrations of basilar membrane bend and activate hair cells
78
what type of channels do hair cells open?
K+ channels
79
what membrane vibrates and activates the hair cells?
basilar membrane
80
frequency theory
groups of neurons in auditory nerve fire at the SAME frequency as original sound source
81
place theory
identifying the frequency of sound depends on the location of maximal vibration on the basilar membrane and which neurons are firing the most
82
sound localization
comparison of arrival times of sounds at each ear and differences in intensities
83
what structure is used for localizing sound in vertical plane?
pinna
84
what are the two types of skin?
- hairy skin
| - glabrous skin (hairless)
85
what are the 3 layers of skin?
epidermis
dermis
subcutaneous
86
what is a mechanoreceptor?
a touch receptor that physically opens and closes
87
meissner's corpuscles
- encapsulated
- rapid rate of adaptation
- small receptive field
- pressure
88
pacinian corpuscles
- encapsulated
- rapid rate of adaptation
- large receptive fields
- vibration
89
merkel's disks
- non-encapsulated
- slow rate of adaptation
- small receptive field
- pressure
90
ruffini's endings
- non-encapsulated
- slow rate of adaptation
- large receptive field
- stretch
91
how is touch info relayed to the brain?
- mechanoreceptors
- dorsal column
- dorsal column nuclei
- VP nucleus of the thalamus
- primary sensory cortex
92
organization of somatosensory cortex
primary - found in postcentral gyrus of parietal lobe
| secondary - found in posterior parietal lobe
93
plasticity of touch
somatosensory cortex rearranges itself in response to changes in the amount of input it receives
94
olfactory stimuli
airborne, dissolve in mucus
95
how are olfactory stimuli detected?
olfactory receptors
96
where are olfactory receptors found?
olfactory epithelium
97
how many olfactory receptors are there?
~1000
98
mcclintock effect
pheromones sensed in the nose by vermonasal organ (VNO), they are released during menstruation stimulating VNO in women. alters hypothalamus output and induces synchronized menstruation
99
glomeruli
structures found in olfactory bulbs that are single receptors (meaning they only respond to one type of receptor)
100
olfactory input to the brain
olfactory cortex projects to the thalamus, limbic system, and neocortex
101
5 categories of taste
```
sweet
sour
bitter
salty
umami
```
102
papillae
located on the tongue
| each contains 1-100 taste buds
103
where are taste receptors located?
in the taste buds which extend microvilli into saliva
104
how is taste info relayed to the brain
- taste receptors
- CN VII, IX, X
- gustatory nucleus
- VPM nucleus of the thalamus
- gustatory cortex
- orbitofrontal cortex in frontal lobe encodes emotional qualities of taste
105
super-taster
have a discriminating sense of taste; fatty and sugary food less appealing, reaction to bitter foods make them less fond of veggies
- 1/4 are super tasters (more women)
- 1/4 are not
- remaining 1/2 are in-between
106
examples of smooth muscle
- digestive tract
- arteries
- reproductive system
107
examples of striated muscle
- skeletal muscle
| - cardiac muscle
108
what is a muscle fiber?
individual muscle cell
109
what surrounds the muscle fiber?
muscle membrane, contains nicotinic ACh receptors
110
what makes up the interior of a muscle fiber?
myofibrils
111
actin
thin filaments
112
myosin
thick filaments
113
process of muscle fiber contraction
1. fully relaxed
- troponin prevents interaction between actin and myosin
- action potential releases Ca2+, which binds with troponin
- myosin and actin are free to interact
2. partially contracted
- myosin binds to actin
- myosin filaments rotate and move relative to actin, shortening the sacromere
3. fully contracted
- reuptake of calcium frees troponin
- troponin blocks interaction of myosin and actin once again
- the filaments slide apart
114
what are the 3 types of myosin filaments
type I fibers (slow twitch)
| type IIa and type IIb fibers (fast twitch)
115
type I (slow twitch)
- predominate in muscles of back, neck, and legs
- use aerobic metabolism
- appear dark red bc of myoglobin
- participates in endurance of movements
116
type II a and b (fast twitch)
- predominate in arms and shoulders
- use anaerobic metabolism
- appear white
- participate in brief, powerful movements
117
antagonistic pairs
allow for movement
118
motor unit
consists of alpha motor neuron and all the muscle fibers it controls
119
muscle spindles
where muscle stretch is monitored and controlled
120
muscle fibers inside the spindle
intrafusal fibers
121
muscle fibers outside the spindle
extrafusal fibers
122
golgi tendon organs
located at the junction between muscle and its tendon that forms a feedback loop that limits contraction
- monitors and controls muscle contraction or force
123
sensory fiber attached to golgi tendon organ
Ib sensory fiber
124
motor cortex
planning, initiating, and directing voluntary movements
125
brainstem centers
basic movements and postural control
126
lateral pathway
serves long distance structures, including hands and feet
127
ventromedial pathway
serves proximal structures, including neck and torso
128
what role does the cerebellum play in movement?
timing of movements and integrates sensory and motor function to provide smooth, coordinated body movements and also error prediction
129
what role does the basal ganglia play in movement?
responsible for the initiation and maintenance of movement
130
major nuclei of the basal ganglia
- dorsal striatum
| - nucleus accumbens
131
steps involved in the initiation of voluntary movement
1. decision to make a movement originates in prefrontal cortex and parietal lobe
2. movement is planned in SMA and PMA, incorporating input from the thalamus, basal ganglia, and cerebellum
3. primary motor cortex sends signals via lateral pathway
4. lateral pathway carries signals to spinal motor neurons , which initiate muscle contraction
132
what type of toxins interfere with motor control?
ACh antagonist
133
what causes myasthenia gravis and how is it treated?
it is an autoimmune disorder that causes extreme muscle weakness and fatigue. can be treated over time using AChE inhibitors
134
what is ALS: amyotrophic lateral sclerosis? what are the possible causes? what factors are associated with increased risk of developing ALS?
- degeneration of the motor neurons in the spinal cord and brain stem
- possible causes: toxins, viruses, SOD-1 gene, and correlation with athletic activity
- higher risk in men than women, also lean and more athletic people are more susceptible when they're older
135
what is Parkinson's Disease? what are the direct causes? what are the treatments?
- progressive difficulty in all movements, especially voluntary movement
- direct cause due to degeneration of dopaminergic neurons in the substantia nigra
- treatment: L-dopa
136
when is genetic sex determined? what determines it?
determined at time of fertilization by sex chromosome
- XX: female
- XY: male
137
examples of sex chromosome abnormalities
- turner syndrome: XO
- klinefelter syndrome: XXY
- XYY
138
gonads
internal organs
- females: ovaries
- males: testes
139
SRY gene
if present then gonads develop into testes, if not then they become ovaries
140
when do internal sex organs develop?
6 weeks, they are undifferentiated. during 3rd month they differentiate
141
wolffian system
develops into seminal vesicles, vas deferens, and prostate
142
mullerian system
develops into uterus, upper vagina, and fallopian tubes
143
external genitalia of females and hormones involved
- labia, clitoris, and outer vagina
| - no hormonal activity required
144
external genitalia of males and hormones involved
- scrotum and testes
| - 5-alpha-dihydrotestosterone needed ( loss results in ambiguous external genitalia )
145
what is androgen insensitivity syndrome (AIS)?
abnormal androgen receptors disrupt normal development of the wolffian system, though testosterone and anti-mullerian hormone are released in normal manner
146
what is congenital adrenal hyperplasia (CAH)?
adrenal glands released elevated levels of androgen
- males, few observable effects
- females, exposed to excessive androgen are born with ambiguous genitalia
147
5-alpha-reductase deficiency
testosterone present in body but can't be converted. at puberty unconverted testosterone produces male secondary sex characteristics
148
organizational effects of hormones
- permanent
- sensitive period
- hormonal effects on the differentiation and development of the sex organs, brain and behavior in early development
149
activational effects of hormones
occurs in fully developed organism, beginning at time of puberty
150
hormonal events that control sexual maturation and the development of secondary sex characteristics at puberty
hypothalamus releases gonadotropin-releasing hormone (GnRH) which then stimulates production of the follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the pituitary which then secretes sex hormones from the gonads
151
secondary sex characteristics in males
testosterone stimulates:
- muscular development
- maturation of external genitalia
- facial hair
- enlargement of larynx (deeper voice)
- hairline on the head (baldness)
152
secondary sex characteristics in females
estradiol stimulates:
- breast growth
- maturation of external genitalia and uterus
- changes in deposition of body fat
- menstrual cycle
153
basic steps of menstrual cycle
- pituitary increases FSH
- follicles develop - ovum
- estrogen stimulates LH release
- LH initiates ovulation
- estradiol - uterine wall
- corpus luteum - progesterone
- hormonal decrease
- menstruation
154
how do hormones affect cognition?
women > men in verbal tasks
- related to higher levels of estrogen
men > women in spatial tasks
- related to higher levels of androgens
155
possible cause to drop in avg. puberty
- increasing rates of obesity
| - increased exposure to estrogen (like compounds)
156
male rats during copulation
- males mate with females only during ESTRUS
- male mounts female
- females exhibit lordosis: receptive posture in which the hindquarter is raised and the tail is turned to the side facilitating intromission by male
- males eventually ejaculate
157
what brain regions are sexually dimorphic?
- sexually dimorphic nucleus of the preoptic area
| - interstitial nuclei of the anterior hypothalamus
158
what hormone is important for male and female sexual behavior?
testosterone
159
aromatization
testosterone is transformed into estradiol, which produces masculinization in many animals
160
alpha fetoprotein
found in the placenta; binds estrogen and prevents maternal estradiol from masculinizing the female brain
161
why are female hyenas masculinized?
their mothers estradiol is not blocked by the placenta like in most other species
162
how does sexual arousal vary between men and women?
men have a direct correlation between physical arousal and subjective arousal whereas women have a disconnect between physical and subjective arousal
163
the coolidge effect
the propensity of an animal that appears sexually satiated to resume sexual activity when provided with a novel partner
164
how do the brains of homosexuals and heterosexuals differ?
INAH-3 are smaller in homosexual men than among heterosexual men
165
what evidence supports the idea that prenatal exposure to androgens is associated with homosexuality?
development of structures not involved in sexual behavior often reflect the influence of prenatal androgen exposure in women
- otoaccoustic emissions
- 2D:4D ratio
166
oxytocin
neurohormone secreted during child birth and lactation; promotes pair bonding
- secreted in thalamus
- important in women
167
vasopressin
neurohormone important in social behavior, sexual motivation, and pair bonding
- found in periphery
- important in men
168
what are the roles of oxytocin and vasopressin in pair bonding?
before mating if the female or male are injected with oxytocin or vasopressin respectively then they bond well with one another. if they are injected with the antagonist of that hormone then they act opposite
169
anisogamy
union between two gametes that differ in size and form
170
sperm competition
the midpiece of the sperm determines swimming speed and power; in species with more promiscuous mating strategies both the testicles and the sperm's midpiece are larger
171
what type of face is particularly attractive?
symmetrical
172
what body type is particularly attractive?
- younger features on females
- masculine men (sexual encounter)
- less masculine men (long-term)
173
what are the 4 biological rhythms?
- ultradian
- circadian
- infradian
- circannual
174
ultradian
less than 24 hours
| - ex: activity
175
circadian
approximately 24 hours
| - ex: sleep/wake cycle
176
infradian
greater than 24 hours
| - ex: menstrual cycle
177
circannual
yearly
| - ex: migration
178
circadian rhythm
any rhythmic change that continues at close to a 24 hour cycle in the absence of external cues
- body temperature
- cortisol secretion
- sleep and wakefulness
179
how long is a free-running circadian rhythm?
24.2-24.9
180
how is a free-running circadian rhythm measured?
zeitgeber
181
how is wheel running used to assess daily activity rhythms?
animals are exposed to 12 hours of light and 12 hours of dark, since they are nocturnal they are more activity at night. even when the light/dark is removed they are still active around the same time due to their internal biological clocks
182
entrainment
process of resetting the biological clock
183
zeitgeber
"time-giver" - the stimuli that an organism uses to synchronize with the environment
184
where is the mammalian master circadian located?
above the optic chiasma in the hypothalamus - suprachiasmatic nucleus
185
when is the SCN most active?
during the day
186
what evidence demonstrates that the SCN is the master circadian clock?
neurons from a heathy hamster can be put into a mutated hamster and that hamster will adapt to the normal ways
187
phase shift
shift in activity in response to a synchronizing stimulus
- spring shift = phase in advance
- fall shift = phase in delay
188
what is the pathway that relays light info to the SCN?
retinohypothalamic pathway
189
melatonin
the hormone of darkness released by pineal gland
190
how does jet lag and daylight savings interfere with the circadian rhythm an melatonin release?
cause a conflict between internal clock and external zeitgebers
191
what is SAD? what systems are involved and how is it treated?
```
Seasonal Affective Disorder
caused by:
- overproduction of melatonin
- serotonergic system dysregulation
- sleep phase delays
treatment:
- phototherapy
- antidepressants
```
192
what are the 3 physiological measures used to characterize wakefulness and sleeping?
- rapid eye movement (REM)
- non-REM (nREM)
- slow wave sleep (SWS)
193
sleep spindles
occur in ~0.5 sec bursts of 12 to 14 hz
194
k-complexes
are sharp negative EEG potentials
195
stage 1 - EEG
theta rhythms
196
stage 2 - EEG
sleep spindles and k-complexes
197
stage 3 & 4 - EEG
delta rhythms
198
when do dreams occur?
during REM and nREM sleep
199
when do the most vivid dreams occur?
during REM characterized by:
- visual imagery
- sense that the dreamer is "there"
200
4 theories of dreams
- hobson & mccarley: activation synthesis theory
- crick & mitchison: forget irrelevant info
- winson: integrate sensory experiences w/ memories
- reveonsuo: threat simulation
201
what brain regions control wakefulness?
- locus coeruleus: releases norepinephrine
| - anterior raphe nuclei: releases serotonin
202
what brain regions control nREM sleep?
- pre optic area of hypothalamus: inhibits wakefulness circuits, has nREM on cells
- LC & RN: norepinephrine and serotonin release decreases, preparing brain for REM sleep
203
what brain regions control REM sleep?
REM on area - rostral pontine reticular formation: responsible for rapid eye movement and muscle paralysis
REM off area - LC & RN: decrease before REM sleep dis-inhibits the pons, after 30 mins of REM the LC & RN reactivate inhibiting the pons
204
dyssomnias
abnormality in the amount, quality or timing of sleep
ex: insomnia, narcolepsy, hypersomnia
205
parasomnias
abnormal behavior or physiology during sleep
ex: nightmares, night terrors, somnambulism (sleepwalking), restless leg syndrome
206
narcolepsy
unwanted sleep attacks
- excessive daytime sleepiness
- cataplexy
- sleep paralysis
207
cataplexy
sudden muscular paralysis while conscious
208
sleep paralysis
similar loss of muscle control during transition between sleeping and waking
209
hypersomnia
characterized by excessive daytime sleepiness
- lack of OR interrupted sleep at night
- nap frequently and inappropriately
- anxiety, irritation, restlessness, slower thinking, memory difficulty
- comorbid w/ many psychological disorders
210
night terrors
- within 4 hours of bedtime
- disoriented, confused
- caregivers: unaware of presence, inconsolable
- no memory of event unless fully awakened
- returns to sleep rapidly unless fully awakened
- partial arousal from deep slow wave sleep
211
nightmares
- late in sleep cycle
- upset, scared
- comforted by caregivers
- vivid recall of dream
- return to sleep often delayed by fear
- REM sleep
212
somnambulism
"sleepwalking"
- occurs during deepest stages of SWS
- they can be woken up without harm
213
REM behavior disorder
REM paralysis absent or minimized
- act out dramatic and/or violent dreams
- shouting and grunting
- voluntary muscles become tonic or tensely contracted
