Unit 3 Flashcards
(108 cards)
1
Q
What is the main function of gastrulation?
A
to define midline, dorsal-ventral and anterior-posterior axis
2
Q
What is the significance of the notochord? (hint: 2 things)
A
define midline and the neural ectoderm (neural precursor cells)
3
Q
What is the difference between the signals promoted by chordin/noggin and BMPs?
A
Chordin/noggin induce the default (neural fate) and inhibit BMPs. BMPs induce an ectodermal state. While chordin/noggin is produced by notochord, BMPs are produced by surrounding tissues
4
Q
An increase in FGF concentration would increase/decrease neural induction?
A
Increase
5
Q
What are the 5 types of cells in the PNS that arise from neural crest cells?
A
Cranial, trunk, vagal, sacral, and cardiac neural crest cells.
6
Q
Arrange the following neural tube closure defects from most common to least common: anencephaly, holoprocenchephaly, spina bifida
A
Spina Bifida, holoprocenchephaly, anencaphaly
7
Q
An increase in the TGF-beta dorsal signal would lead to an increase in the neural fate or the epidermal fate?
A
Epidermal fate because of the increase in BMPs
8
Q
What is the major function of Shh?
A
Formation of neural plate and neural groove
9
Q
What are two consequences of inhibitting Shh?
A
loss of cell differentiation regulation (cancers) and polarity (holoprocenchepaly/cyclopia)
10
Q
What divisions does A/P patterning create?
A
Divisions between rombencephalon, mesencephalon and prosencephalon + spinal cord
11
Q
Which directional patterning do HOX genes control?
A
A/P patterning of posterior CNS
12
Q
What defects arise in mice that lack OTX (hox genes) patterning?
A
Forebrain structures destroyed
13
Q
In early development, so neural stem cell divide symmetrically or asymmetricall?
A
symmetrically
14
Q
How to neurons and glia arise?
A
From neural progenitor cells
15
Q
What is the pattern of division for neural stems cells and neural progenitor cells?
A
NSCs: symmetrical, asymmetrical, symmetrical Neural progenitors: symmetrical and asymmetrical at any time
16
Q
How does delta keep the surrounding cells in their pluripotent NSC state while differentiating themselves?
A
The delta from the target cell causes the Nnearby cell to become too activated, shutting its own proneural bHLH
17
Q
What are the two significant morphological characteristics of growth cones?
A
Lamellapodium: actin filaments and microtubules Filopodia: extend from lamellopodia, actin filaments
18
Q
When a growth cone senses a repulsive stimuli, what happens to its F-actin?
A
F-actin binding proteins bind to it
19
Q
Which of the following are responsible for elongation vs. direction: microtubules and f-actin
A
Microtubules: elongation
20
Q
What is the structural difference between axon guidance and growth cone guidance?
A
actin vs. f-actin
21
Q
What is it more difficult for axons in the CNS to regenerate vs axons in the PNS?
A
The CNS ECM is mainly composed of such repulsive molecules as hyaluronan, tanascin and aggrecan, while PNS has collagen, laminin and fibronectin
22
Q
What are two similarities between CAMs and Cadherins?
A
CAMS and cadherins are both attractive molecules with homophilic binding
23
Q
What are two differences between CAMs and cadherins?
A
CAM: calcium independent, cytoplasmic kinase causing bundling of axons while they grow cadherins:calcium dependent, actin binding and organization
24
Q
Where in the optic tectum is the highest concentration of ephrins?
A
Posterior tectum
25
Where are netrins secreted?
Midline of embryo
26
If a mutation in a commisural axons causes it to express UNC5 before it has crossed the midline, what will happen?
It will be repelled by the midline and will not cross it
27
If there is a mutation on the commisural axon preventing it from producing Robo receptors, will it cross the midline?
The axon will cross back over to the original side because DCC will not be inhibited (attracted to the netrin at the midline) and slit will have no influence because Robo is missing
28
What are the relevant synaptogenic molecules at the NMJ and CNS?
NMJ: agrin--\> MuSK--\> rapsyn--\> AchR CNS: Neurexin (presynap), neuroligin (postsynap)
29
Name 2 differences between Trk and p75 receptors
Trk prefers cleaved neurotrophins while p75 prefers them unprocessed and is activated by ALL
30
What is the exchange facilitated by the Na/K ATPase pump?
3 Na+ ions out for 2 K+ ions in--\> maintaining the gradient
31
Interstitial hypokalemia is due to: 1. cell hyperpolarization 2. cell depolarization
1.
32
What limits the time course of Vm?
The membrane capacitance magnitude
33
What limits the membrane potential change?
The membrane conductance
34
If the Na/K ATPase malfunctions and becomes slower, causing the [Na+] outside the cell to decrease, how will the action potentials change?
They will become slower and smaller in peak
35
Where are the cell bodies of the olfactory neurons located?
Olfactory epithelium
36
Describe the olfactory pathway
Olfactory receptor--\> OE--\> cribiform plate--\>olfactory bulb--\> thalamus/hypothalamus/hippocampus
37
If an overwhelming assult on your nasal receptors occurs, what will happen to the regeneration of the olfactory neurons?
The basal cells will increase division and their might be some incorrect rewiring of the neurons
38
Which of the following ions is responsible for the depolarization due to an odorant interacting with an olfactory receptor? a. Cl- b. Na+ c. K+ d. Ca2+
d
39
How is one olfactory receptor able to recognize lots of different odorants?
It is broadly tuned and is able to focus on the one molecular component they all have in common
40
How does the olfactory epithelium help contribute to the diversity of odors that are recognized?
It has a spatial pattern on the epithelium depending on odorant response
41
How many olfactory receptor types does one neuron express?
just one
42
What is the fundamental unit of anatomical and physiological organization in the olfactory bulb?
The neuropils called glomeruli
43
What is the order of the layers around the olfactory bulb?
Glomerular, external plexiform, mitral and granule
44
If the periglomerular and granule cell are destroyed around the olfactory bulb, what will happen to odor integration? (306)
The inhibition on the mitral cells will be lost and relay to olfactory cortex will be continuous and unregulated.
45
How to glomeruli surround the olfactory bulb help distinguish odors?
All the neurons expressing a single Olfactory receptor type from a quadrant specific expression zone converge on one glomeruli thus distinguishing receptors and odor types
46
are OR low affinity or high affinity receptors?
low affinity (broadly tuned)
47
What is the change of transmission for taste?
cranial nerves VII, Ix, X--\> NTS--\>VMP/Hypothal/amygdala--\> insula/frontal cortex
48
What is the major difference between taste buds and olfactory cells?
Taste buds are not bonified neurons while olfactory cells are
49
In what histological layer are the taste buds embedded?
Squamous stratified epithelium
50
What is the difference between salt/sour and sweet/bitter receptors as related to their signal transduction?
Salt/sour rely on ionic transduction while sweet/bitter rely on G-protein coupled mechanism
51
Which artery supplies the inner retina?
52
When the lens thickness is increased by the contration of the ciliary muscles, what happens to the focal length of the object?
53
What is presbyopia?
54
How would you correct a case of hypermetropia (focal length too long)?
positive/convex lenses to decrease focal length
55
A 75 year old patient with diabetes, and exposure to sunlight comes into your office complaining of cloudy vision and glare. What is this likely and what is the treatment?
56
A patient with loss of peripheral vision comes into your office with high blood pressure and increased intraocular pressure. What is this likely and what is the treatment?
57
Your patient with sudden onset of glacouma seems to have an obstruction between the iris and the cornea. Is this an open/closed-angle and does the IOP increase?
this is closed-angle and IOP increases
58
What the two levels of synaptic interactions in the retina?
Inner and outer plexiform layers
59
In which cell layer in the retina is the photoreceptor cell body found?
60
What is the difference between the outer plexiform layer and the inner plexiform layer?
The outer plexiform has synapses for photoreceptor, bipolar and horizontal cells while the inner plexiform has synapses for bipolar, amacrine and ganglionic cells
61
What are the cell involved in vertical/horizontal information flow in the retina? and what neurotransmitters do they use?
vertical: photoreceptor, bipolar and ganglionic: glutamate
horizontal: amacrine and horizontal: GABA/glycine
62
What is the difference in the inner and outer segment of the photoreceptors? (rod/cones?)
Inner segment: housekeeping machinery
outer: phototransduction machinery
63
When faced with intense light, will rods and cones depolarize/hyperpolarize? Will then increase release of glutamate or decrease?
Hyperpolarize/decrease
64
In the case that the self-renewing capabilities of cis-retinal were halted, what would happen to the rhodopsin and to the levels of cMP and transducin?
rhodopsin would not be activated, cGMP levels would stay increased and transducin would not be activated. This would lead to no hyperpolarization and eventual blindness
65
Where is the free all-trans retinal re-converted to cis-retinal?
Pigment epithelium (this is the visual cycle)
66
Suppose the instead of the fovea being largely populated by cones, it was populated by rods and the periphery was populated by cones. How would this change the properties of the fovea?
The fovea would have lower resolution and higher sensitivity and spatial acuity would be low
67
Your patient presents with tunnel vision, night blindness. She has a family history of this situation. The ERG is negative. What is this likely?
Retinitis pigmentosa (loss of rods and eventually cones)
68
When we see our world in indoor lighting, are we using mostly cones or rods or both equally?
Mostly cones because of phototopic vision requiring color and in bright lights
69
As you look as a a black circle with a light spot in the middle, which ganglionic cell (on/off center) is depolarized?
The on-center
70
Your 75 year old patient complains of loss of central vision preventing him from doing everyday tasks. You suspect that this is macular degeneration and send the man for testing for drusen deposits. Is it preferable that the patient comes back with +/- drusen results?
Negative because that would likely make this a wet AMD which is treatable with laser coagulation of vessels and injections. Dry AMD can only be slowed with antioxidants
71
Your diabetic patient is asking you about possible complication that her conditions could present in the future. You want to explain to her some of the issues that she could have down the road with her vision. What should you say?
Diabetic retinopathy is a complication and occurs in 80% of diabetics of over 10 years. It leads to blocked vision due to incompetent blood vessels and can be treated with laser surgery
72
Where does the first synapse in the visual system occurs?
The outer plexiform layer, where the bipolar, horizontal and photoreceptors synapse
73
True or false? Both photoreceptors and bipolar cells have graded potentials?
True
74
As a flash of light hits a cone, what are the changes that take place in the cone and in off-center bipolar and ganglionic cell? also glutamate release
The cone will hyperpolarize, their will be a decrease in glutamate and the off-center bipolar cell will hyperpolarize, and the off-center ganglionic cell will not fire
75
Match the following colors to the cone type:
1. green 2. red 3. Blue
a. Short b. medium c. long
Long- red
Medium: green
short: blue
76
Protanopes and deuteranopes have difficulty distinguishing between:
1. red and green
2. reds and blue
3. blue and green
1.
77
How is the parvocellular pathway similar to cones in functionality?
Both are color sensitive with high acuity that recieve input from a single cell unlike rods with integrate information from many cells
78
In Traquair's island of vision, which point would have the highest peak?
The fovea because it is the most sensitive point of the island
79
Which of the following characteristic of the eye does not affect visual sensitivity?
1. age
2. attention
3. pupils size
4. ciliary muscle strenght
5. refractive status
6. media opacities
4.
80
What is the cardinal difference in the kinetic and statis perimetry?
While in kinetic perimetry, the object is moved and the sensitivity is determined as it is moving, in statis perimetry, the brightness/intensity of stimuli is varied
81
Your patient is missing a block of her visual field. What type of visual field defect is this?
1. Quadrantonopia
2. Scotoma
3. Hemianopia
4. Arcute
2
82
Where do the retinal ganglionic fibers traveling from the retina synapse?
Lateral geniculate nucleus
83
Retinal and optic nerve lesions can both display this type of visual defect:\_\_\_
Scotomas
84
A lesion in the body of the optic chiasm will probably yield what type of visual defect?
A bitemporal hemianopsia
85
The most posterior to the chiasm a lesion occurs on the pathway, the most (congruous/incongruous) the defect will be
Incongruous
86
A patient in your office comes in with incongruous homonymous hemianopia with normal pupillary reflexes. Where is the lesion?
In the lateral geniculate nucleus
87
What kind of trauma is macular sparing usually a result of?
Infarcts
88
Your patient shows signs of right incongruous homonymous superior quadrantanopia (pie in the sky). Where is the lesion likely?
Temporal Optic radiations
89
How is a visual cortical area and its boundaries determined and defined?
According to photoreceptor densities
90
What are the four major destinations of the retinal ganglionic axons?
91
name the point in space where both eyes and their foveas converge
The single fixation point
92
What is the pattern of layering in the LGN laminae, ventral to dorsal? Which of them are the parvocellular layers?
Contra, ipsi, ipsi, contra, ipsi, contra. The last four are parvocellular
93
Where in the visual pathway do single neurons first receive binocular input?
The visual cortex, NOT LGN
94
What is another name for the optic radiations running through the temporal lobe?
Meyer's loop
95
How does the parvocellular pathway maintain the high acuity system from a small receptive field?
It has the midget system where one cone connects with a midget bipolar cell and a midget ganglionic cell.
96
Why do red and green/blue and yellow appear on opposite sides of the color wheel?
97
What property of visual cortical neurons, discovered by hubel and wiesel, was essential in establishing the higher order computing abilities of the visual system?
The orientation tuning: neurons prefer certain ANGLES of light
98
What are the four main properties of the architecture of the V1?
Orientation tuning, ocular dominance, retinotopy, and cytochrome oxidase
99
How does a 1mm x 1mm hypercolumn perform to analyze all possible values of orientation and OD for the V1?
it contains values from the R and L alternating OD, including the CO blobs as well as the orientation colums running orthagonal to it.
100
Where does the thick stripe of the V2 extrastriate cortex usually project to?
101
A lesion in the Medial-temporal area (V5) of the cortex would lead to what defect?
A defect in motion sensing abilities
102
A lesion in the dorsal/parietal stream in the visual pathway would lead to what defect?
A defect in the ability to know the WHERE of an object
103
Your patient seems to have little awareness of the left side of her body or her environment. What kind/where is this defect?
This is a right sided parietal lobe defect resulting in a loss of the WHERE sensation
104
Prosopagnosia, the inability to recognize faces, results from a defect in which lobe?
Temporal lobe since this is a WHAT problem
105
Describe the experiment that Simon LeVay performed to find that ODC are not developed in fetal animals.
106
Why do children who developed cataracts and get treated later develop amyblopia (lazy eye)?
They missed the critical period where the cortical connections needed to be developed. Otherwise the good eyes takes over the territory of the 'bad' eye
107
Your infant patient with cataracts just had surgery to replace the lens. You are still concerned about amblyopia, what type of therapy is not required?
108
Through which mechanism is the non-deprived eye able to encroach on the territory of the deprived eye?
Hebbian mechanism (cells that fire together wire together)
