Exam 2 Flashcards
1
Q
action potential is 100 mV, which is approximately ____ times greater than a single EPSE
A
100
2
Q
action potential lasts approximately…
A
1 msec
3
Q
action potential goes from…
A
rest to the rising phase to the overshoot, falling phase, and then the undershoot
4
Q
action potential is all or none, meaning…
A
that theres either an action potential or these isnt, no inbetween or incomplete ones
5
Q
the Na+ channel is a single peptide with…
A
four separate domains
6
Q
each of the 4 domains of the Na+ channel has___ transmembrane alpha helices that are labeled ____
A
6; s1-s6
7
Q
the pore loop of the Na+ channel is located between…
A
S5 and s6
8
Q
the pore loops of the Na+ channel act together as…
A
a selectivity filter
9
Q
the s4 alpha helix has…
A
+ amino acids that act as the voltage sensor and detect the voltage across the membrane
10
Q
the alpha helix in the Na+ channel that detects the voltage changes is….
A
the s4 alpha helix
11
Q
the s4 voltage sensor of hte Na+channel physically opens when…
A
the voltage reachs -40 mVor higher, which then allows Na+ to enter the cell down its concentration gradient
12
Q
the s5 and s6 selectivity filter of the Na+ channel is selective by…
A
being shaped exactly for the ion the pore channel is a gate for. so in this case it is the exact size of an Na+ moecule paired with 1 water molecule. hydrated K+ ions don’t fit because theyre too large.
13
Q
the Na+ channel has a resting voltage of…
A
-65 mV
14
Q
once Na+ flows into the cell, ____ blocks the Na+ channel so that it can fall back to rest
A
the globbular “ball” protein portion of the Na+ channel. once back to rest the ball swings away so the pore can close again
15
Q
local anestetics work by…
A
getting into th epore channel of Na+ so it is physically blocked so no action potential can occur so no pain is felt.
16
Q
teh two types of potassium channels are the…
A
leak channels (open all the time/not voltage gated) which are responsible for resting membrane potential. the other is the voltage gated K+ channel (delayed rectifiers) that open with a delay.
17
Q
the voltage gated K+ channels are called “delayed rectifiers” because…
A
they sense a voltage change during the rising phase but do not open right away. when they do open, K+ flows outward. these are responsible for the falling phase of the action potential (becomes more negative as a result of K+ leaving the cell)
18
Q
undershoot follows the…
A
falling phase
19
Q
during the undershoot, ____ channels are open
A
leak and K+ gated channels which means theres a larger K+ conductance and therefore the voltage goes down below resting to the EK+
20
Q
the cell goes back up to resting from an action potential when…
A
the K+ gated channels close and there is no longer a loss of + charge from the leaving of K+
21
Q
during the rising phase and overshoot of the action potential, ___ is open so there is a net inflow of Na+
A
Na+ gated channels
22
Q
over evolution, the coretex has expanded to have…
A
an outer layer, large surface area and be highly convoluted
23
Q
because the cortex has expanded so much, there is space in the brain for other functions such as…
A
cognition, thinking, planning, strategy, etc
24
Q
the central sulcus is the divide betweem the…
A
frontal and parietal lobes
25
in the mammalian brain, the cerebrum has ___ sections
two sections
26
the left side of the cerebreum is responsible for...
recieving the sensory info for the right side of the body - there is a crossover in the brain
27
the cerebellum "litte brain" as much more tightly packed neurons than the...
cerebrum although the two has the exact same number of neurons
28
the left side of the cerebellum recieves infromation from....
the left side of the body, there is NO crossover in this section of the brain
29
the brain stem is responsible for regulating...
breather, conciousness, temperature control, ad other vital functions
30
the further into the brain you travel, the _____ the functions are
more basic
31
the spinal cord functions in...
sending info into and from the brain
32
there are ____ meningal membranes in the human brain
3
33
the meningies in the brain are...
the dura matter, the arachnoid membrane, and pia matter
34
a subdural hematoma is when blood collects in the subdural space between...
the dura matter and teh arachnoid membrane
35
pia matter is located...
right on top of the brain
36
the subarachnoid space is filled with...
cerebrospinal fluid
37
the ventricular system is the...
fluid surround the brain and spinal cord, helps protect the brain
38
cerebral spinal fluid is protected by...
tissues
39
the choroid plexus in the lining of the ventricles functions in...
filtering blood that is then reabsorbed into the subarachnoid space
40
the retina develops from the...
optic vesicles
41
the tekencephalic vesicles develop into the...
cerebral hemispheres
42
the edge of the optic cup becomes the...
retina
43
the optic stalk becomes the...
optic nerve
44
neural tube birth defects occur when the...
neural tube does not close corectly (ie spina bifida and anencephalo)
45
spina bifida is when...
the spine does not close or develop properly
46
anencephalo occurs when there are insuffient levels of folic acis and causes...
neural tube defects
47
having sufficent levels of folic acid during fetal development can prevent 70-90% of all...
neural tube defects
48
the neural tube differentiates into the ___ brain
forebrain
49
the thalamus is in the...
center of the brain
50
the thalamus acts as...
a relay station for sensory systems except for smell. your thalamus is turned off when youre asleep.
51
the superior colliculus...
recieves visual info, moves the head/eye towards visual stimulus
52
the inferior colliculus...
recieves auditory stimulus, moves the head towards sound
53
the cerebral aqueduct is where...
cerebrospinal fluid circulates
54
the tegmentum has the sibstantia nigra which plays a role in...
movement, this is the area damaged in aprkinsons disease
55
the tectum includes the...
superior colliculus, the inferior colliculus and the cerebral aquesduct
56
the midbrain consiststs of the...
tectum and the tegmentum
57
the dorsal portion of the hindbrain becomes teh...
cerebellum which functions in coordination of movement, motor memory storage
58
the dorsal horn of the spinal column send...
sensory info to the brain
59
the ventral horn of the spinal column sends...
motor info to muscle cells
60
the most common neurodegenerative disease is...
alzheimers
61
symptoms of AD include...
memory problems,language impairment, disorientation, problems with abstract thinking, judgement problems, and personality changes that all result from the death of brain cells
62
in AD neurofibillary tangles accumulate intracellularly and ____ forms extracellularly
amyloid plaques
63
the neurofibillary tangles and amyloid plaques of AD cause cell death i the brain and is most severe in the...
hippocampus
64
amyloid plaques are composed of...
Beta amyloid which is a peptide about 39-42 amino acids long, it is cut from the amyloid precursor protein (APP) a transmembrane protein
65
beta amyloid (aka amyloid beta, AB) is cut from APP by...
beta and gamma secretases
66
in AD, normal amounts of amyloid beta are produced but...
they are not cleared at normal rates
67
in normal function amyloid beta works to...
regulate synaptic activity (dampens it)
68
there is evidence the amyloid beta may...
inhibit yeast infections
69
just as in CTE, in AD tangles of the tau protein becomes...
hyper phosphorylated, microtubules disassemble, axonal transport stops, and eventually neurons die
70
the cortex and hippocampus shrink in...
AD
71
the gene for APP (on chr 21, people with downs syndrome have higher risk), PSEN-1, PSEN-2, and APOE all impact...
AD
72
PSEN-1 and PSEN-2 both code for proteins that are a componet of gamma secretase which...
makes more of the 42 amino acid beta amyloid which builds up easier because its larger
73
APOE (apolipoprotein E) codes for a component of VLDL and functions to...
remove cholesterol from the blood and amyloid beta plaques from the brain. different forms of the gene have different benefits for fighting AD. E2 is rare in population btu helps fight AD, e3 is most common and has no effect on AD, e4 is a risk factor because it has a low efficencey
74
acetylcholine esterase inhibitors normally breaks down ACh but the drug...
inhibits ACh breakdown so that you have more transmitter in teh synaptic cleft which helps to improve cognition, mood, and behavior in AD patients
75
behaviorla and dietary risk factors for AD include...
high calorie diet, high fat diet, sedentary lifestyle, low education level, history of head trauma
76
antiboides against amyloid plaques worked well in mice but...
did not work in humans, instead people develped increased fluid pressure in and around the brain, the brain became inflammed, and there was too large of an immune response in the brain
77
the cancer drug targretin turns on the APOE gene and in the mouse models...
amyloid plaque levels droped by 25% within 6 hours and by 50% in 72 hours. also restored some normal behaviors. currently in clincal trials for humans
78
the somatic sensory system is responsible for...
sense of touch, vibration, pain, temperature, and proprioception
79
primary afferent axons bring sensory info to the brain and their cell bodies are in...
the dorsal root ganglion, one part of the axon then goes out to the skin/muscle/tendon and the other portion goes to the spinal cord via the dorsal roots
80
axon and non neural tissue have free nerve endings that detect..
pain and temperature, they are the only ranched axons here
81
the axons in the skin contain...
mechanosensitive ion channels that respond to stretching or tension in the cell membrane
82
primary afferent axons vary in...
diameter and myelin composition. the fastest axons have the greatest diameter and myelin
83
the fastest primary afferent axon is...
the A alpha that send information about body position from muscles and tendons
84
the second fastest primary afferent axons are...
A beta, which function to carry info about touch, vibration, and pressure to the brain
85
the slowest primary afferent axons are...
c fibers, the smallest of these axons that lacks myelin. they function in sending info to the brain about pain, temp, and itch
86
the second slowest primary afferent axons are...
A delta which carry information about pain and temp
87
A alpha and A beta send nfromation to the brain via the ___ pathway
the dorsal column-medial lemniscal pathway
88
the dorsal column-medial lemniscal pathway for A beta and A alpa axons runs...
up the spinal column on the same side they enter where they then go into the ipsilateral dorsal column. then it reaches the first synapse at the brain stem. the second order neuron then crosses over to the other side and runs up to relay in the ventral posterior thalamus. the 3rd order neuron then goes to the primary somatosensory cortex.
89
the primary somatosensory cortex (s1) is located...
in the parietal lobe behind the central sulcus in the post central gyrus. this is bilateral and there is crossover (left side of body=right somatosensory cortex)
90
Penfield's map shows...
the location of the sensory input for each part of the body in the brain
91
hands, face,and fingers are overrepresented in S1 which is why...
they are much more sensitive
92
teh two slowest axons, c fibers and A delta, carry information about...
pain
93
the first pain detector is...
a delta , which causes a sharp pain
94
the second pain detect is...
the c fibers, causes dull, throbbing pains and burning sensations
95
both A delta and c fibers have ion channels that respond to...
a lot of mechanical stimulation: it takes a lot of pressure to actually feel pain instead of pressure in a given area. they also respond to temperature when its high enough to cause damage (ie: burns) and to chemicals if its something corrosive like lactic acid and histamine
96
A delta and c fibers have 6 different...
transient receptor channels (TRP)
97
the TRP of a delta and c fibers have...
different sensitivities to temperature: some detect cold and some detect heat th cold receptors can also be activated by menthol and heat receptors can also be activated by capsaicin
98
the pathway that the c fibers and A delta follow is...
the spinothalamic pathway
99
in the spinothalamic pathway, axons...
synapse as soon as they enter the spinal column. then the second order neurons cross over to the contralateral side and ascend to the thalamus. the 3rd order neurons then go from the thalamus to the primary somatosensory cortex
100
if someone has unilateral damage on the right side of their body on the spinal cord, what sensations would you expect to be lost?
the person would lose the ability to detect touch, vibration, 2 point discrimination and proprioception below the lesion on the right side/SAME SIDE of the body and they would lose the ability to detect pain and temperature on the left side/opposite side of the body below the lesion
101
pain is reduced by...
the simulataneous activation of mechanoreceptors (ie rubbing your skin where it hurts reduces the pain. this happens because A alpha and A beta axons activate inhibitory interneurons that reduce the activity of the spinothalamic tract
102
the descending pain control pathway controls...
how much pain goes into the brain
103
stimulation of PAG in the midbrain produces pain relief by...
projecting to the dorsal horn of the spinal cord which then activates the inhibitory interneurons in the spinothalamaic tract. morphine works by binding to the opoid receptors in the PAG which lead to inhibitiion. natural endorphins also work this way
104
teh two slowest axons, c fibers and A delta, carry information about...
pain
105
the first pain detector is...
a delta , which causes a sharp pain
106
the second pain detect is...
the c fibers, causes dull, throbbing pains and burning sensations
107
both A delta and c fibers have ion channels that respond to...
a lot of mechanical stimulation: it takes a lot of pressure to actually feel pain instead of pressure in a given area. they also respond to temperature when its high enough to cause damage (ie: burns) and to chemicals if its something corrosive like lactic acid and histamine
108
A delta and c fibers have 6 different...
transient receptor channels (TRP)
109
the TRP of a delta and c fibers have...
different sensitivities to temperature: some detect cold and some detect heat th cold receptors can also be activated by menthol and heat receptors can also be activated by capsaicin
110
the pathway that the c fibers and A delta follow is...
the spinothalamic pathway
111
in the spinothalamic pathway, axons...
synapse as soon as they enter the spinal column. then the second order neurons cross over to the contralateral side and ascend to the thalamus. the 3rd order neurons then go from the thalamus to the primary somatosensory cortex
112
if someone has unilateral damage on the right side of their body on the spinal cord, what sensations would you expect to be lost?
the person would lose the ability to detect touch, vibration, 2 point discrimination and proprioception below the lesion on the right side/SAME SIDE of the body and they would lose the ability to detect pain and temperature on the left side/opposite side of the body below the lesion
113
pain is reduced by...
the simulataneous activation of mechanoreceptors (ie rubbing your skin where it hurts reduces the pain. this happens because A alpha and A beta axons activate inhibitory interneurons that reduce the activity of the spinothalamic tract
114
the descending pain control pathway controls...
how much pain goes into the brain
115
stimulation of PAG in the midbrain produces pain relief by...
projecting to the dorsal horn of the spinal cord which then activates the inhibitory interneurons in the spinothalamaic tract. morphine works by binding to the opoid receptors in the PAG which lead to inhibitiion. natural endorphins also work this way
116
lower motor neurons have their cell bodies in the...
ventral horn of the spinal cord. here they make synaptic contact with muscle fibers - Neuronmuscular junction! this is controlled by the upper motorneurons in the brain
117
proprioceptors are sensory receptors that...
tell the brain about body position. they are associated with muscles and tendons
118
proprioceptors are found in...
muscles spindles and golgi tendons
119
intrafusal muscles fibers function to...
monitor muscle length
120
intromuscle fibers are wrapped with ...
Ia sensory axons. the axons are activated when the muscle is stretched and the mechanoreceptors in the axon are activated.
121
the two different types of lower motorneurons are...
alpha motorneurons and gamma motor neurons
122
alpha motorneurons synapse on...
extrafusal fibers
123
gamma motorneurons synapse on...
intrafusal fibers within the muscle spindle
124
both alpha and gamma motorneurons are activated at the same time because...
otherwise there would be no tension generated in the muscles and the brain would recieve no information about it
125
both alpha and gamma motorneurons are located in...
the ventral horn of the spinal cord
126
when alpha and gamma motorneurons are activated (mechanosentivie) and there is tension in the muscles,...
Ia sensory axon is then activated and it sends information to the brain
127
the golgi tendon organ is located between the tendon and the muscle and it..
monitors muscle tension, associated with the IB sensory axon
128
the two descending spinal tracts for motorneurons are...
the lateral and ventromedial
129
the lateral descending spinal tract is composed of...
the corticospinal and rubrospinal tracts
130
the lateral descending spinal tract is responsible for...
voluntary control of distal muscles
131
the ventromedial pathway is composed of the...
tectospinal and vestibulospinal tracts
132
the ventromedial pathway is responsible for...
controlling posture - central muscles!
133
the rubrospinal tract is the one responsible for...
gross movements, no fine motor skills from this
134
the corticoprinal tract is responsible for...
fine motor skills. can still move if this is damaged but you would have gross movements only
135
teh basal ganglia does not...
send signals directly down the spinal cord
136
the basal ganglia functions to...
initiate wanted movements and inhibit unwanted movements
137
the diseases associated with the basal ganglia are...
PD, huntington's and tourettes
138
the frontal and sensory cortexes come together to provide...
info to the basal ganglion where the signals then go to the thalamus and then out to the motor cortex
139
the globus pallidus of the basal ganglia has neurons that are...
spontaneously active which inhibits the thalamus
140
to allow movement to take place, the globus pallidus must...
be turned off
141
the glous palladius is turned off by activating...
the putaman
142
the putaman is activated by...
the frontal cortex and teh substantial nigra
143
in PD, neurons in the _____ dies which leads to less activation of the putaman and therefore less deactivation of teh basal ganglion so movement cannot happen
substantial nigra
144
teh cerebellum functions in...
coordination of sequences of movements, storing motor memories, and in two way communication between the cerebellum and the motor cortex. also recieves sensory info and detects motor error (difference between intended motion and actual motion) reduces motor error since it can observe it
145
the photoreceptors of the retina develop from...
the optic cups
146
axons of ganglion cells make up the...
optic nerve
147
the ganglion cells of the optic nerve...
fire action potential
148
the bipolar cells and photoreceptors of the retina/eye...
have graded electrical responses
149
the fovea is located at...
the very center of the retina
150
bipolar cells and ganglion cells are bent away from the fovea so...
light has direct access to photorecptors which is why we can see most clearly at the fovea
151
rods are ____ light sensitive than cones
more
152
rods and cones differ from other nerve cells because...
they have outer segments composed of disks where the photopigments are stored
153
the outer segment on rods is larger than the one on cones which means...
there is more photopigment and therefore are ~1000s times more light sensitive than cones
154
rods are used for _____ vision
night
155
since rods only have one type of photopigment...
at night time we cant see in color
156
there are 3 different types of cones that differ in...
the type of photopigment that they have
157
cones are in the ____ and rods are in the ___
fovea; periphery
158
in the peripheral retina...
many rods converge onto one ganglion cell which is good for low light conditions but not for seeing details
159
there is a 1:1 ration of cones to ganglion cells whcih is good for...
seeing details
160
the process of converting light into an electrical signal is called...
phototransduction
161
photoreceptors depolarize in dark conditions (become less negative) which causes...
neurotransmitters to be released in the dark, there is a Na+ current through the sodium channels
162
photoreceptors polarize in the light (become more negative) which causes...
neurotransmitter to no longer be released
163
the photopigment in rods is...
rhodopsin
164
rhodopsin is composed of...
the protein opsin and retinal (a small molecule within opsin)
165
retinal is made by...
vitamin A (poorer night vision when vit. A deficient)
166
when light is detect in dark conditions, the photon energy is absorbed by the retina and then...
retinal chnages in conformation which then activates opsin
167
when rhodopsin is activated by light, a G protein (transductin) is activated. this then...
activates phosphodiesterase which converts cGMP to GMP. GMP does not hold the Na+ channels open so they close and the cells become more negative since theres no influx of Na+
168
there are three different opsins in cones:
red blue and green, they all absorb different wavelengths
169
the two classes of bipolar cells are...
on and off
170
off bipolar cells depolarize when...
light is off.
171
on bipolar cells depolarize when...
light is on
172
photoreceptors release the neurotransmitter glutamate and...
on/off bipolar cells both have different glutamate receptors which allows them to respond to light on and light off
173
off bipolar cells have "normal" or AMPA glutamate receptors that...
bind when the light is off, causing the off bipolar cell to depolarize
174
on bipolar cells have a G-protein cpupled glutamate receptor (mGluR6) and when....
glutamate binds here the cells hyperpolarize
175
when on bipolar cells depolarize, on ganglion cells...
fire action potentials, same happens for off ones
176
when the center of vision is dark, there is an...
increase in the rate of firing action potentials
177
when both the center and the surroundings are dark,
there is an antagonistic response because one makes action potentials increase and the other makes them decrease
178
there are also m and p types of...
on/off ganglion cells
179
m type on/off ganglion cells...
cover a larger area of the retina and have a transient burst of action potentails they also detect motion
180
p type on/off ganglion cells have a...
smaller receptive field, sustained action firing potential and detect shapes of objects
