Exam 2 Flashcards
(179 cards)
1
Q
poikilothermic
A
body temperature same as environment
2
Q
homeothermic
A
warm blooded
better at heating than cooling
3
Q
what is the sensor for hemeothermic
A
pre-optic area
4
Q
what releases IL-1
A
leukocytes
5
Q
what are leukocytes activated by
A
bacteria
virus
fungus
6
Q
IL-1 does what
A
used during a fever
increases synthesis of prostaglandin
7
Q
what does prostaglandin do
A
activates receptors in preoptic area
8
Q
what does preoptic area activate
A
it activates the autonomic nervous system to raise body temperature
some bacteria grow less at higher temps
9
Q
homeostasis involves what two types of behavior
A
reflexive (degrading fats) and overt (searching for food)
10
Q
where to make lesion for rats to become obese
A
ventromedial hypothalamus
VMH
11
Q
what is the normal role of the VMH
A
to stop eating behavior
12
Q
where to make lesion for rat to stop eating
A
lateral hypothalamus
LH
13
Q
what is the normal role of the lateral hypothalamus
A
to initiate eating behavior
also augments taste sensation, facilitates ingestion and swallowing, regulates ANS regulation of digestion
14
Q
electrical stimulation of the LH produces what
A
stimulation-bound feeding
SBF
15
Q
at high stimulation currents, LH stimulation supports what
A
brain-reward stimulation (via DA)
16
Q
two signals for the onset and offset of hunger
A
a fast neural signal
a slow hormonal signal
17
Q
what is believed to explain why someone has pain after having a limb removed
A
the touch fibers going into the substantia are always active to some degree, and even in the absence of pain there is a baseline of activity in touch fibers
18
Q
what act as fast hunger-off signals
A
signals from stomach and from the mouth
19
Q
food going straight into stomach
A
intragastrically
20
Q
sham-fed
A
food never reaches stomach
21
Q
what happens if an animal is sham-fed
A
they will eat more than animals that aren’t sham-fed, but they will still stop eating at some point
22
Q
constant hedonic value
A
if starving, then shitty food is very pleasurable
if very full, really good food is still tempting
23
Q
what causes bulimics to binge
A
a bulimic finds food equally pleasurable regardless of hunger state
24
Q
stomach distension
A
a fast hunger off signal from the stomach
25
vagus nerve
connects stomach with VMH
26
what happens if you cut the vagus nerve
stomach distension no longer signals satiety
27
does the VMH receive fast or slow signals
fast
28
caloric content of food is a fast hunger off signal from the stomach via what nerve
splanchnic
29
blood is a fast or slow hunger off signal
slow
30
the original glucostatic theory
sites in brain (LH) have receptors that measure glucose levels in the blood that when no longer activated initiate LH activity and eating behavior
31
what is the problem with the original glucostatic model
diabetics have very high blood glucose level because they don't have enough insulin but they're always starving
32
hyperphagic
very hungry
33
diabetics show that it's not _____ that is the slow hunger off signal, but it is _____
it's not blood sugar
it is intracellular glucose
34
role of insulin
transfers glucose into cells
without it, glucose will not enter most cells
35
what is the problem with the glucostatic theory once we know that glucose needs to be inside the cells
most brain sites don't need insulin to absorb glucose from the blood into the cells, so the diabetic's brain should have plenty of glucose and therefore wouldn't be hyperphagic
36
glucose receptors are not in the ___ but in the ___
not in the brain
in the liver
37
where does glucose need to be injected to satiate hunger
in liver or hepatic portal vein (directly to liver)
38
what happens when energy levels are high from high glucose levels
liver signals the brain via increased activity of inhibitory afferents from vagus nerve to LH to stop eating
39
what happens when energy levels are low from low glucose levels
liver signals the brain via decreased vagus nerve activity to initiate eating
LH is disinhibited
40
lipostatic theory
the brain indirectly measures fat by measuring free fatty acids
41
the two stages of lesioning the VMH
dynamic phase: lots of eating
| static phase: eating curbs and a new constant but very high weight is set
42
how do you alter your weight set point
increasing the number of fat cells in body in early years, aka overfeeding
43
VMH lesion is altering what to make the rat gain weight
metabolism
44
insulin is released by what
islet cells of the pancreas
45
insulin increases the conversion of glucose to what
glycogen (happens in the liver; glycogen is stored form of glucose)
fats
46
insulin facilitates the transport of fats into where
adipose tissue
47
fats are stored as what
triglycerides
48
triglycerides are what
glycerol and fatty acids
49
order from which glucose is used in the body
blood stream
glycogen in muscles and liver
stored fat cells (breaks down into three fatty acids)
muscle
50
gluconeogenesis
getting glucose from muscle
51
glucagon is released by what
the islet cells of the pancreas
52
what does glucagon do
when blood glucose levels fall, its release causes glycogen to be broken down into glucose in the liver
also breaks down fats into fatty acids
can break down fatty acids into ketones
53
VMH activation inhibits what
secretion of insulin by the pancreas
54
when a VMH lesion disinhibits insulin release, what does this result in
excess insulin and excess fat storage, or not enough free fatty acids for energy
so even if an animal eats a lot, it can't be used for energy
55
where is the fat signal monitored
the liver monitors free fatty acid levels
56
what happens when free fatty acid levels are high
the liver signals hunger (disinhibits LH)
57
when are fatty acid levels high
when there is little food in the body and fat is broken down for energy
58
VMH
stop eating behavior
stop hunger
59
LH
start eating behavior
start hunger
60
LH is disinhibited by
low glucose levels in liver
it is disinhibited via decreased activity of inhibitory vagus nerve inputs to LH
61
stimulation of the LH increases release of what
insulin
62
lesions of the LH result in what
decrease in insulin levels
breakdown of fat to FFAs
63
In summary, the stomach has receptors for ____ ____ and ____ ____, and sends a ____ ____ ____ signal via the ____ ____ to the ____
In summary, the stomach has receptors for stomach distension and caloric content, and sends a fast hunger off signal via the vagus nerve to the VMH
64
In summary, the liver has receptors for ____ and ____ ____ ____, and sends a ____ ____ ____ signal to the ____
In summary, the liver has receptors for glucose and free fatty acids, and sends a slow hunger on signal to the LH
65
bulimia includes higher than normal levels of ___ and lower than normal levels of ___
higher levels of NPY
lower levels of CCK
66
homonculus
a visual representation of how much of the sensory cortex is dedicated to each body part
67
the more ___ the larger the part of the map of sensory cortex that is dedicated to that body part
receptors in the area
68
the receptors for touch, pressure, and vibration are
dendrites of sensory neurons located within specialized end organs
69
what is the gold standard of end organs
pacinian corpuscle
70
what do end organs do
transmit specific stimuli to receptors, which transduce the stimuli to neural impulses
71
pacinian corpuscles
pressure
72
how is a pain stimulus transduced
free nerve endings of sensory neurons
73
end organs use what kind of ion channels for touch and pressure
mechanically gated
74
what kind of ion channels for pain
chemically gated
75
what chemical is released at beginning of pain transmission
endotoxins
these are released by dying or injured cells
76
what do endotoxins activated
chemically gated ion channels on free nerve endings of dendrites
77
how many pairs of spinal nerves
31
78
above the neck, cutaneous facial information reaches the brain via which cranial nerve
fifth
| trigeminal
79
cervical
neck
80
thoracic
chest and upper back
81
lumbar
lower back
82
sacral
down to base of spinal cord, coccyx
83
all spinal nerves are mixed nerves which means what
they have both sensory and motor axons, and as you leave the spinal cord there are two subgroups
84
two subgroups of spinal nerves
dorsal and ventral
85
dorsal
input
| sensory
86
ventral
output
| motor
87
dermatome
a region of the skin innervated by an individual spinal nerve
therefore there are 31 dermatomes below the neck on each side of the body
88
why do dermatomes overlap
if a nerve gets cut, you can still get info from that area via other dermatomes
89
three types of sensory neurons
A-beta fibers
A-delta fibers
C-fibers
90
A-beta fibers
touch and pressure
thick and myelinated
fastest
91
A-delta fibers
pain
medium and myelinated
middle speed
92
C-fibers
pain
thin and unmyelinated
slow
93
is pain or touch transmitted faster
touch
A-beta fibers are thickest and myelinated
94
which fiber carries fast sharp pricking stabbing pain
A-delta
thicker than C-fiber and myelinated
95
which fiber carries slow throbbing burning aching pain
C-fibers
thin and unmyelinated
96
cutaneous info reaches brain via two ____ neural systems
ascending
97
what are the two ascending neural systems
```
dorsal column (medial lemniscus)
anterolateral tract
```
98
is there a synapse for touch fibers
no
99
decussation
crossing over of the axon traveling to the other side of the brain towards thalamus
100
from spinal cord to brain for cutaneous information
no synapse of touch fibers
touch axons head to medulla
synapse in medulla in same side of body as original axon
next axons cross over to other side to thalamus
filtering of info in thalamus: either carries on to somatosensory cortex or it stops
101
when do you first feel the touch sensation
when the impulse reaches the somatosensory cortex AFTER it has gone through medulla and thalamus
102
axons leave in a tract from the medulla, what is this called
medial lemniscus
this is what crosses over to opposite side
103
after the medial lemniscus crosses over, it picks up axons of what
picks up axons of the trigeminal nerve carrying touch and pressure info from head and face
104
after the medial lemniscus crosses over and picks up axons of trigeminal nerve
heads to thalamus and synapses
105
from the thalamus, info is sent to what places
primary or secondary somatosensory area
106
primary somatosensory area
receives only ipsilateral information
107
secondary somatosensory area
receives touch and pressure info from both sides of the body (mostly face)
108
relationship between pressure and generator potential for A-beta
greater pressure means greater generator potential in dendrites of A-beta neurons
with continued pressure, there is adaptation
109
the stronger the stimulus, the _____ the ____ ____ of a neuron
the higher the firing rate
110
pain info comes in through ____ region of the spinal cord and synapses in ____ ____
dorsal region
| dorsal horn
111
where do pain axons release neurotransmitter
onto the next axons on the opposite side of spinal cord
112
what system has A-delta and C-fibers
anterolateral system
it must split for us to tell the difference
113
nociceptors
respond to injury
the free nerve endings of A-delta and C-fibers
114
tissue injury releases what
histamine and other endotoxins that act upon chemically gated ion channels
115
pain fibers conduct to terminals in ___ ___ of spinal cord in layers ___ and ___. ___ ___ is released here
dorsal horn
1 and 5
Substance P
116
3 pathways that comprise the anterolateral system
spinothalamic tract
spinomesencephalic tract
spinoreticular tract
117
spinothalamic tract
thalamus
fast pain
C-fiber
118
spinomesencephalic tract
limbic, emotion
slow pain
A-delta
119
spinoreticular tract
reticular formation, medulla
alert and awake
pay attention to throbbing slow pain
A-delta
120
which tract/tracts are affective/motivational aspect of pain
spinomesencephalic
spinoreticular
slow, emotion aspect of pain
121
which tract/tracts are sensory/discriminative aspect of pain
spinothalamic
| fast pain, where the pain is
122
neuralgia
inflammation of peripheral nerves
123
causalgia
gunshot
124
interneurons are where in the dorsal horn
layers 2 and 3
| the substantia gelatinosa
125
why do A-beta fibers interact with A-delta and C-fibers via interneurons
to inhibit pain transmission
"closing the gate"
126
what happens if you lose A-beta inhibition
pain transmission is disinhibited
| chronic pain
127
narcotic analgesics
in layers 2 and 3 of dorsal horn
| tell spinal cord to block pain info
128
____ induces releases of ____ ____ from opioid interneurons in ____ ____. These ____ inhibit release of ____ ____, causing ____
Serotonin induces releases of opioid peptides from opioid interneurons in dorsal horn. These opioids inhibit release of Substance P, causing analgesia
129
Axon of ____ synapses onto axon of ____ ____ that is releasing ____ ____. ____ sends axons down into spinal cord into layers ____ and ____ of ____ ____ (____ ____) to activate ____.
Axon of interneuron synapses onto axon of pain fiber that is releasing substance P. Midbrain sends axons down into spinal cord into layers two and three of dorsal horn (substancia gelatinosa) to activate interneurons.
130
____ and ____ are two major ____ brain sites. They don't ____ pain info, but they send out pain ____ signals through ____ ____. This means they send ____ down to ____ pain.
PAG and NRM are two major analgesic brain sites. They don't receive pain info, but they send out pain suppressing signals through descending inhibition. This means they send axons down to inhibit pain.
131
When activated, the ____ releases our own internal ____, ____ (which is like morphine), which activates ____ ____. Opiate drugs activate the ____ and ____.
When activated, the interneuron releases our own internal opiate, enkephalin (which is like morphine), which activates opiate receptors. Opiate drugs activate the PAG and NRM.
132
____ bind onto the ____ of pain axons. There are opiate ____ on the axon ____ of the ____ axons, ____ substance P release.
Endorphins bind onto the terminal of pain axons. There are opiate receptors on the axon terminals of the pain axons, suppressing substance P release.
133
The more you activate ____ and ____, the more you ____ the ____ system. You can never completely do this because ___________
The more you activate PAG and NRM, the more you suppress the anterolateral system. You can never completely do this because this stuff only happens in two layers of the dorsal horn.
134
opiate narcotics
naturally occurring pain-relievers from poppy
| morphine and codeine
135
two synthetic drugs with morphine-like actions
heroin
| demerol
136
applying morphine to where produces analgesia
PAG
NRM
dorsal horn
137
analgesia
inability to feel pain
138
transduction
stimuli from the environment are converted into electrical signals (EPSP/IPSP) by the receptor
139
tinnitus
loud sounds have killed off hair cells in ear, remaining ones are damaged
always hear ringing
140
light produces IPSP or EPSP
IPSP
141
darkness produces IPSP or EPSP
EPSP
142
hair cells produce IPSP or EPSP
EPSP
143
only when action potential reaches ____ do we feel stimulus
cortex
144
receptors convert stimuli in environment into ____ ____ on sensory neuron
generator potentials
145
Before the sensory neuron, generator potentials are ____ ____. After the sensory neuron, they are ____ ____ ____.
Before the sensory neuron, generator potentials are graded potentials. After the sensory neuron, they are all-or-none action potentials.
146
a receptor that is sensitive to a particular environmental stimulus is
a stimulus-gated ion channel
147
A stimulus alters the ____ of the ion channel on the ____. It is usually an ____ ion channel. It usually ____ the ____ of the ____ channel and produces ____.
A stimulus alters the permeability of the ion channel on the receptor. It is usually an Na+ ion channel. It usually increases the permeability of the Na+ channel and produces depolarization.
148
generator potential
the change in membrane potential on the receptor
149
Generator Potential
bigger stimulus =
longer stimulus =
bigger stimulus = bigger generator potential
| longer stimulus = will end early sometimes due to adaptaion
150
Action Potential
bigger stimulus =
longer stimulus =
bigger stimulus = more action potentials closer together
| longer stimulus = more action potentials closer together but get further apart as stimulus goes on
151
The generator potential spreads ____ using ____ properties. It is ____ and ____. The ____ of the generator potential is ____ to the ____ of the ____. ____ generator potentials are needed to produce an ____ ____ at the ____ ____.
The generator potential spreads passively using cable properties. It is graded and decremental. The magnitude of the generator potential is proportional to the strength of the stimulus. Many generator potentials are needed to produce an axon potential at the sensory neuron.
152
The greater the ____ of the summated generator potentials, the greater the ____ of the action potentials.
The greater the magnitude of the summated generator potentials, the greater the frequency of the action potentials.
153
why does adaptation occur for touch
the end organ gets physically distorted when it's touched and fluid sloshes around... dendrites start moving around, opens mechanically-gated ion channels. after a while the sloshing stops and end organ accepts its new shape
154
the two forms of coding of sensory info
anatomical and functional
155
anatomical coding
different modes of stimuli (visual, taste, etc) travel via sensory neurons to different areas of the brain
156
anatomical coding: law of specific nerve energies
Johannes Muller
"the nature of a sensory message is determined by the specific sensory pathways that are activated"
157
functional coding
within a different kind of stimulus, different intensities are determined by the frequency of action potentials arriving at the location (loudness, brightness)
158
frequency for hearing
pitch
159
amplitude for hearing
loudness
160
wave form shape for hearing
timbre
161
Sensory information contains both a ____ aspect (via ____ to ____ ____) and a ____ aspect (via ____ ____)
Sensory information contains both a discriminative aspect (via thalamus to sensory cortex) and a motivational aspect (via reticular formation)
162
how can you increase the ability of the brain to distinguish between two stimuli arriving in the sensory cortex
stimulate reticular formation
163
prosopagnosia
inability to recognize familiar faces
damage to parts of brain involved in high-level interpretation of sensory input
164
blindsight
a case of agnosia--missing last part of sensory info
all sensory systems work up until the conscious awareness part
165
true/false
sensory receptors always consist of mechanically gated ion channels
false
166
true/false
the generator potential is an all-or-none neural impulse
false
167
true/false
c-fibers are involved in transmitting touch and pressure
false
168
true/false
for the most part, medium diameter/moderately myelinated pain fibers carry sharp pain
true
169
true/false
touch fibers first synapse in the spinal cord
false
170
true/false
morphine acts to alleviate pain in the spinal cord as well as the brain
true
171
neurons involved in suppressing pain within the substantia gelantinosa via descending inhibition probably originate in the
periaqueductal gray
| PAG
172
true/false
according to the opponent process theory of motivation, removal of stimuli in the environment associated with drug use increases the A process
false
173
a person suffering from chronic pain who is treated with the removal of the thalamus is most likely to say
the pain bothers me just as much but i can't describe the pain
174
the pacinian corpuscle is capable of adaptation
true/false
true
175
a gunshot to the back of the head is most likely to disrupt
vision
176
the reticular formation is considered the active relay station of the brain
true/false
false
177
methods of eliminating a conditioned response
extinction
| counter conditioning
178
touch receptors contain ion channels most sensitive to
mechanical deformation
179
the sensation of hue is associated with changes in
frequency of light
