Last Half Of Semester Flashcards
(217 cards)
1
Q
Corticospinal pathway function
A
Motor: controls fine movement of the face and extremities
2
Q
Rubrospinal Pathway function
A
Motor: controls voluntary coarse movements excluding mouth, toes and fingers
3
Q
Tectospinal Pathway Function
A
Motor: Controls orienting towards a stimuli
4
Q
Reticulospinal Pathway function
A
Motor: controls stabilization of movement on uneven surfaces
5
Q
Vestibulospinal Pathway Function
A
Motor: controls posture and balance maintenance during head movement
6
Q
Medial Lemniscus function
A
Sensory: measures fine touch, body position (proprioception) and vibration
7
Q
Corticospinal pathway originates where?
A
In the Motor Cortex
8
Q
Corticospinal pathway crosses the midline where?
A
In the Lower Medulla
9
Q
Rubrospinal Pathway originates where?
A
In the red nucleus of the midbrain
10
Q
Rubrospinal Pathway crosses the midline where?
A
It crosses immediately
11
Q
Tectospinal Pathway originates where?
A
Superior colliculus in the midbrain
12
Q
The tectospinal pathway crosses the midline where?
A
It crosses immediately
13
Q
The reticulospinal pathway originates where?
A
Reticular formation in the pons/ medulla
14
Q
The reticulospinal pathway crosses the midline where?
A
It mostly doesn’t cross the midline
15
Q
The vestibulospinal pathway originates where?
A
in the vestibular nuclei in the medulla
16
Q
The vestibulospinal pathway crosses the midline where?
A
Trick! It doesn’t cross the midline
17
Q
The medial lemniscus sensory pathway originates where?
A
In the dorsal root ganglia
18
Q
The medial lemniscus pathway crosses the midline where?
A
In the lower medulla
19
Q
The auditory pathway originates where?
A
In the cochlea
20
Q
The auditory pathway crosses the midline where?
A
In the pons
21
Q
The visual pathway originates where?
A
In the eyes, duh
22
Q
The visual pathway crosses the midline where?
A
In the Optic chiasm
23
Q
Which pathway travels through the LGN of the thalamus?
A
The visual pathway
24
Q
Which pathway travels through the LGN of the thalamus?
A
The auditory pathway
25
Tuning Curve
Example: A neuron in the motor cortex fires most when a monkey moves in a particular direction, and the firing get less and less as the arm’s direction moves farther from that “preferred” direction.
26
The primary motor cortex’s role in creating movement is:
Planning and execution of a particular movement
27
The premotor cortex ’s role in creating movement is:
The selection of appropriate motor plan to accomplish a task
28
The supplementary motor cortex ’s role in creating movement is:
Control of complex sequences and bilateral movements
29
The basal ganglia ’s role in creating movement is:
Gating of proper movement initiation
30
The cerebellum ’s role in creating movement is:
Balance and coordination of ongoing movement
31
The brainstem’s role in creating movement is:
Basic movements and postural control
32
What are the two consequences to a lesion to the pyramids of the medulla?
1) loss of fine motor control because the corticospinal tract is disrupted
2) Rubrospinal track takes over those movements but is less precise, as it is the evolutionary precursor to the corticospinal pathway.
33
EEG measures what?
Electrical activity recorded from the scalp
34
MEG measures what?
Changes in magnetic fields caused by neuronal firing
35
ECoG measures what?
Electrical activity recorded on the surface of the brain
36
PET measures what
Movement of radioactive tracers
37
FMRI measures what?
Changes in blood oxygenation over time
38
FcMRI measures what?
Functional connectivity of brain regions
39
What major artery supplies blood to areas of the frontal, parietal and temporal lobes?
Middle Cerebral artery
40
Broadmann divided up the cortex into 52 regions based on what?
Cytoarchitecture (the arrangement of cells in a tissue, especially in specific areas of the cerebral cortex characterized by the arrangement of their cells and each associated with particular functions
41
Disorders of speech “content” are called _______________ and are more associated with damage to which hemisphere of the brain?
Aphasia, associated with left hemisphere damage
42
Disorders of speech “affect” (intonation and gestures) are called _________________ and are associated with damage to which hemisphere?
Aprosodias, associated with the right hemisphere
43
Speech production is most commonly associated with speech ___________________?
Production
44
Speech comprehension is most commonly associated with which part of the brain?
Wernicke’s area
45
Fluent speech, normal comprehension, but cannot repeat words after you- which type of aphasia and where is the damage located?
Conduction aphasia located in the accurate fasciculus (white matter tract connecting Broca’s and Wernicke’s area)
46
What are the three unique characteristics about Einsteins’s brain?
1) Overdeveloped parietal lobe
2) Sylvia’s fissure was pushed forward relative to the normal position
3) His brain was wider than normal in this region
47
What are the three types of plasticity?
Morphological/ developmental
Functional
Adult
48
What’s an example of morphological/ developmental plasticity?
Changes to the mouse barrel cortex after removing whiskers at birth -
OR Changes to ocular dominance columns in visual cortex after closing one eye at birth
49
What’s an example of functional plasticity
Learning a second language [and developing a new functional region for the second language distinct from the first language in Broca’s area]
50
What’s an example of adult plasticity
Visuomotor adaptation (like me in the prism goggles!)
51
The stripes in layer IV of the primary visual cortex are called _______________
Ocular dominance columns
52
What’s the significance of the ocular dominance columns?
The stripes show that information from each eye is kept separate through the LCN, into layer IV of the visual cortex (they are alter combined in other layers of the visual cortex).
These “stripes” were made visible by injecting dye into one of the animal’s eyes, so that it dyed only the parts of the cortex receiving inputs from the that eye.
53
Which two scientists performed the “closing one cat’s eye at birth” experiment?
Hubel and Wiesel
54
What’s the significance of monocular deprivation (Hubel and Wiesel experiment)
Ocular dominance columns corresponding to the closed eye became narrower, those corresponding to the open eye became wider. Basically, the brain adapted to make the best use of cortical space.
55
What molecular mechanism can cause Hebbian changes (that we learned about earlier in this course)?
Ocular dominance columns corresponding to the closed eye
became narrower, those corresponding to the open eye
became wider. Basically, the brain adapted to make the best
use of cortical space
56
True or false: The sodium current is equal and opposite to the potassium current at the peak of the action potential?
True
57
True or False: Saltatory propagation of action potentials takes place only in invertebrate animals like the giant squid
False
58
True or False: A neuron in the CNS may receive both EPSPs and IPSPs which may cancel each other out
True
59
True or False: Many channels involved in sensory perception, such as the TRPV1 channel which is activated by both heat and capsaicin, are cation selective channels permeable only to sodium ions and calcium ions
False
60
True or False: After a hydrated potassium ion enters the pore of a potassium channel, strategically placed
oxygen atoms of the channel selectively filter substitute for the oxygen atoms of the waters of
the hydration shell
True
61
True or False: Some leak potassium channels remain open at the peak of the action potential
True
62
True or False: The passive propagation of an electrical signal is necessary for active propagation, but active propagation is not necessary for passive propagation
True
63
True or False: In the action potential voltage cycle, the sodium and potassium currents are equal and opposite at rest, at the threshold voltage, at the peak of the action potential, and at the bottom of the undershoot
True
64
True or False: At the peak of the action potential the membrane potential is equal to the sodium ion equilibrium potential
False
65
True or False: The sodium current is equal and opposite to the potassium current in a resting cell
True
66
True or False: At the reversal potential of a channel, the net current through the channel is zero
True
67
True or False: Some ion channels have a reversal potential equal to the equilibrium potential of an ion
True
68
True or False: At the reversal potential of an ionotropic glutamate receptor, there is no net flow of either sodium or potassium ion through that open channel
False
69
True or False: At the reversal potential of an ionotropic glutamate receptor, there is no net flow of electrical current through that open channel
True
70
True or False: The mGluR1 and AMPA receptors both trigger a second messenger cascade that amplifies the signal
False
71
True or False: Small molecular weight neurotransmitters are used only for ionotropic neurotransmissions
False
72
True or False: Xanax is a serotonin uptake inhibitor and Prozac facilitates the activation of GABA receptors
False
73
What Experiment did Roger Sperry run and what were the phenomena/ chemicals that explain the results?
1) cutting a frog’s optic nerve and rotating the eye 180º
| 2) Chemoaffinity and Ephrins
74
What is the effect of Alpha bungarotoxin and curare?
Blocks AcH ionotropic receptors
75
What’s the effect of muscarine toxin?
It activates metabotropic receptors
76
What’s the effect of scorpion toxin?
It retards sodium channel inactivation
77
What’s the effect of tetrodotoxin?
It blocks sodium channels
78
True or False: Active propagation is required for passive propagation
False
79
True or False: Passive propagation is required for active propagation
True
80
True or False: MePPs are small depolarizations of the muscle cell membrane due to the spontaneous release of neurotransmitter in the presences of a stimulus
False
81
True or False: a MePP is the result of the spontaneous release of a synaptic vesicle containing a neurotransmitter
True
82
Myelin Sheath __________ capacitance
Decreases
83
Myelin sheath ___________ resistance across the cell membrane
Increases
84
Myelin ___________ the speed of the action potential propagation down the axon
Increases
85
Propagation of an electrical potential along an axon would be impossible by passive propagation alone because:
Passively propagated signals decay with distance
86
A receptor potential decreases in amplitude with distance from its site of initiation because it is a ____________ potential
Passive
87
The process through which the action potential jumps from one node of Ranvier to the next is ? ___________
Saltatory conduction
88
Electrical potential:
The difference between two points in a circuit or between a point and the ground
89
The rate of change transfer, measured in coulombs
Current
90
The aggregate charge carried by one mole of monovalent ions
Faraday
91
The measure of difficulty that a current encounters in its flow through an object
Resistance
92
A charge storing device consisting of a pair of conducting surfaces separated by a non-conductor
Capacitor
93
Why is a potassium ion able to leave its hydration shell behind when passing through a potassium channel?
Oxygen atoms within the channel mimic the position of the oxygen atoms within the water of the inner K+ hydration shell.
94
Which has a larger crystal radius? Sodium or potassium?
Potassium
95
The use of hydration shells is essential in our understanding of the ________ of ion channels
Selectivity
96
Which ion moves into neurons via voltage gated ion channels and is an important
second messenger involved in neurotransmitter release into the synaptic cleft?
Ca2+
97
When an action potential occurs in the motor neuron at the neuromuscular junction, the amplitude of the excitatory postsynaptic potential (EPSP) depends on the concentration of extracellular Ca2+ because:
The higher the [Ca2+] the more Ca2+ enters the presynaptic terminal through voltage-gated Ca2+ channels and more synchronous release of the synaptic vesicles from the presynaptic terminal occurs if more Ca2+ enters
98
GAD is an enzyme that catalyzes the inter-conversion of?
Glutamate to GABA
99
In normal naming convention of the CNS pathways, you begin at the _______________ and end at the ______________
1) origin, 2) target
100
In a lateral view of the brain, the pathway responsible for facial movements is ________________ to the tract responsible for foot movement
Inferior
101
In a lateral view of the brain, the pathway responsible for facial movement is ______________ to the tract responsible for foot movement
Inferior
102
If stabbed in the back on the left side of the dorsal spinal column at C7 (cutting the dorsal root) what symptoms should you see?
Loss of sensation in the left hand
103
What makes up the diencephalon?
The hypothalamus, the epithalamus and the thalamus
104
Cauda equina
Horse’s tail
105
Dorsal horn
Sensory
106
Ventral horn
Motor
107
Ganglion
Groups of somas
108
Decussation
Crossing the midline
109
Pons
Bridge
110
Pulvinar
Pillow
111
Geniculate
Knee
112
True or false: sensory nerves are afferent while motor nerves are efferent
True
113
In the visual pathway, information from the retina passes through cranial nerve # _____________ “the ___________ nerve” before entering the _______________ of the thalamus
2, Optic, lateral geniculate nucleus
114
In the auditory pathway, info from the cochlea passes through cranial nerve # _____________ , “the ______________ nerve”, and is eventually transmitted indirectly to the ________________ of the thalamus
VIII, vestibulocochlear, medial geniculate nucleus
115
Cells that sense color
Cones
116
Cells sensitive to low levels of light
Rods
117
Cells necessary for vision
Photoreceptors
118
Auditory sensory receptors
Hair cells
119
Sensitive to movement, vibration, light pressure, pain and temperature
Skin touch receptors
120
Define: adequate stimulus
The form of energy a sensory neuron is most sensitive to
121
Define: threshold sensitivity
Amount of stimulus needed to activate a sensory neuron
122
Define: adaptation
The process by which a receptor stops responding to a repeated stimulus
123
Define: receptive field
The area in which a stimulus will activate a particular receptor
124
True or false, The threshold to pressure differs over the body, which reflects different innervation densities. For example, there is lower innervation density in the fingers and lips
False, there is greater inner action density in the fingers and lips
125
What organization principle fo the Nervous system did the mouse’s whiskers experiment results indicate?
The peripheral body maps to the somatosensory cortex
126
Biogenic amines are responsible for
Addiction
127
An example of a snare protein
Syntaxin
128
What cleaves synaptobrevin at inhibitory synapses
Tetanus
129
Conus is...
A soup of peptide neurotoxins
130
What toxin depolarizers sensory neurons which carry pain?
Apamin
131
Which alkaloid stimulates ACH receptors?
Nicotine
132
What is required for the final phase of LTP
Protein synthesis
133
How does Prozac function?
It inhibits the re-uptake of a small molecular weight matabotropic neurotransmitter
134
What is oxytocin?
A peptide metabotropic neurotransmitter/hormone that makes you feel good about babies/ cuddling
135
Normal human genetic variation shows that two individuals are likely, on average, to have a difference (SNP) in their DNA every ________________ nucleotides
500
136
What specific property of voltage-gated sodium channels permits the sequential release of energy in the adjacent axon membrane to propagate the action potential?
Voltage-gating (duh)
137
What type of mutation is likely to be recessive except in rare cases of haplo-insufficiency?
Loss-of-function mutations in a single gene
138
What’s an example of a genetic syndrome caused by a dominant (gain of function) mutation?
Epilepsy, HKPP and NaV1.7 pain responses
139
What’s an example of an autoimmune disease that affects the nervous system?
MS, Myasthenia gravis, LEMS
140
What’s one type of ligand-gated ion channel that has a reversal potential approximately halfway between the equilibrium potential of sodium and potassium ions?
ACH receptor OR GLU receptor (NMDA, Kainate, AMPA)
141
What’s a neurotransmitter that can activate both metabotropic and ionotropic receptors in different brain areas?
ACH or GLU
142
Name a low molecular weight neurotransmitter whose action is stopped by being broken down into two components by acetylcholine esterase.
Acetylcholine... duh (ACH)
143
The enzyme glutamate decarboxylase (GAD) converts glutamate into what inhibitory
neurotransmitter?
GABA
144
Spatial summation
An IPSP and an EPSP are produced on different dendrites of the same neuron, and when they arrive at the cell body, they cancel each other out, producing neither a depolarization nor a hyperpolarization
145
Temporal summation
A subthreshold EPSP in the postsynaptic terminal of an interneuron produces no action potential at the spike initiation zone, but when the presynaptic neuron is fired very rapidly, the EPSPs ride on top of one another and finally reach threshold.
146
Mono synaptic facilitation
Action potentials arriving at the presynaptic terminal leave an accumulation of Ca2+ eventually resulting in increased neurotransmitter release.
147
Synaptic depression
A succession of action potentials arriving in a presynaptic terminal produces successive IPSPs in the postsynaptic cell that decline in amplitude.
148
Long-Term Potentiation (LTP)
Involves the insertion of AMPA receptors in the postsynaptic membrane which results from intense synaptic activity. It also involved the entry of Ca2+ into the postsynaptic cell after sufficient activation and de- blocking of NMDA receptors
149
In cells with an internal [Cl-] higher than the external [Cl-], activating the GABA receptor channels when the cell is at rest will cause the cell to _______________
Depolarize
150
In cells with an internal [Cl-] higher than the external [Cl-], the equilibrium potential is (positive? Negative? Equal to zero?)
Positive
151
In cells with an internal [Cl-] higher than the external [Cl-], activation of the GABA receptor will result in _______________
Cl- flowing out of the cell
152
True or false: driving force of an ion is the difference between the membrane potential and the equilibrium potential of an ion (measured in voltage)
True
153
True or false: gamma frequency waves (~40 Hz) in the cortex are associated with consciousness attentiveness
True
154
True or false: the potent sodium channel blocker tetrodotoxin can be ingested without dire consequences because it is rapidly broken down by digestion
False
155
True or false: the action potential refractory period is a major factor determining the unidirectional travel of action potentials
True
156
True or false: in voltage clamp experiments, the voltage is controlled while the current varies over time
True
157
True or false: passive propagation is necessary for active propagation, but not the other way around
True
158
True or false: the mechanism of ion selectivity in voltage-dependent ion channels limits the movement of water into and out of cells
True
159
True or false: when the NA/K ATPase is positioned, a cell’s resting potential immediately goes to 0
False
160
True or false: scorpion toxin prevents inactivation of voltage-sensitive NMDA receptors
False
161
True or false: In voltage (patch) clamp experiments, single channel currents may be analyzed with respect to their single channel conductance, selectivity, gating characteristics and channel mean open time.
True
162
True or false: Myelin serves two major roles: 1. Lowering membrane resistance to increase the length constant, and; 2. Raising membrane capacitance to conserve energy.
False
163
True or false: spatial summation applies only to EPSP’s and not IPSP’s
False
164
True or false: each element fo circuitry in the brain can be thought of as a computer AND as a batter
True
165
True or false; Each synapse in the CNS closely resembles the NMJ with regard to the number of vesicles released.
False
166
True or false: The bulk concentration of calcium ion always remains constant in the presynaptic terminal, even during intense synaptic activity.
False
167
True or false: Even without the Na+/K+ ATPase most cells would have a negative intracellular potential.
True
168
True or false: Saltatory conduction refers to active propagation jumping from internode to internode at the speed of light.
False
169
True or false: Gain-of-function mutations are mostly recessive while loss-of-function mutations are mostly dominant.
False
170
True or false: The only output of a digital computer is a series of voltage blips corresponding to one’s and zero’s.
True
171
True or false: Coding of information in the brain has a striking similarity to the coding of information in digital computers
False
172
Define: Law of specific nerve energies
Depolarization of neurons in a pathway is interpreted as a particular form of stimulation
173
What is the location factor of thresholds?
Threshold to pressure differs along the body, reflecting different innervation densities (ie lips and ends of fingers are the most sensitive)
174
What’s the fiber type factor for thresholds?
Thresholds to mechanics force (pressure) differ for endings associated with different fiber sizes- smaller forces activated myelinated faster conducting fibers (Aß) Greater forces are required to activated unmyelintaed/ thin myelinated slower conducting fibers (A∂, and C)
175
What is neuromorphological developmental plasticity?
Changes in brain structure deterred by inputs available during development. It has a limited time window (critical period) and is structural plasticity
176
What 3 major features control the “gate” (tonic glues pallidus internal segment inhibition of the thalamus)
1) direct de-inhibition pathways from the cerebral cortex
2) Direct de-inhibition pathways from the substantia nigra (dopamingergic D1- “gas”)
3) Indirect de-de-de-inhibition from substantia nigra (dopaminergic D2, “brake”)
177
What are the 10 steps (in order) of Nervous Embryology?
1. First positional axis is set (animal vs vegetal)
2) Fertilization (defined by sperm entry)
3. Cortical rotation (creates dorsal/ventral axis)
4. Second positional axis set (dorsal/ventral
5. 3rd positional axis set relative to Spemann organizer (anterior/posterior)
6. Blastulaton
7. Principle germ layers formed (ecto, meso, endo)
8. Gastrulation (endo/meso involuted through blastopore)
9. Neurulation (formation of neural tube/ neural crest cells)
10. Cephalization then segmentation (anterior enlargement and segmentation for spinal specialization)
178
What experiment studied neuron fate depending on axon targets (Victor Hamburger)
Chick limb buds were removed from growing embryo, and loss of atonal targets results in the stunting of neuronal development in that area (target innervation determines which neurons survive)
179
What experiment (by Hamburger, Levi-Monalcini and Cohen) discovered nerve growth factor?
They transplanted a mouse tumor next to a developing chick spinal cord, and found that the presence of the sarcoma caused axon sprouting due to a “diffusible factor “ secreted by the tumor called NGF
180
Define Equilibrium potential
Membrane voltage at which there is no net flow of an ion through a channel
181
Define Reversal potential
Pertains to channels; membrane voltage at which there is no net flow of CHARGE through a channel
182
What is whole-cell patch clamping?
A recording pipet creates tight contact between the tip and the plasma membrane, then through strong suction the membrane breaks while maintaining contact, allowing the pipette to have direct access to the cytoplasm
183
What is “outside-out” patch-clamp recording
Like whole-cell configuration, first the pipette has direct access to the cytoplasm, the the pipette is retracted from the cell and the broken ends of the membrane anneal, allowing access to the extra cellular domains of the ion channel
184
What is inside-out patch clamp recording?
The recording pipette uses mild suction so as to not break the membrane and expose the cytosol, but the pulled membrane breaks away from the cell and allows access to the cytoplasmic domain of the ion channel
185
What are the two forms of short-term plasticity?
Monosynaptic facilitation and monosynaptic depression?
186
Define monosynaptic facilitation
Multiple stimulation’s in the pre-synaptic neuron causing larger PSPs in the post-synaptic neuron. This is caused by calcium building up in the presynaptic terminal after each simulation. (It’s a method of learning at the cellular level)
187
Define monosynaptic depression
The PSPs get smaller and smaller with each stimulation because the readily releasable pool of vesicles gets depleted
188
What are two forms of synaptic integration?
Temporal summation and spatial summation
189
Define temporal summation
The EPSPs do not have time to return to baseline because the action potentials of the presynaptic neuron are firing too quickly, so the EPSPs build one on top of the other like steps, which may eventually lead to an action potential
190
Define spatial summation
Summation over distance, where multiple neurons are sending signals to a single postsynaptic neuron causes the postsynaptic potentials to build one on top of the other
191
What are the three different type of metabotropic signaling?
Gs: increases cAMP —> stimulated PKA
Gi: decreases cAMP—>inhibites PKA
Gq: increases Ca2+—> activated PKC
192
What type of receptors are metabotropic? (General)
G-Protein coupled receptors (GPCRs)
| ~The largest gene family of receptors~ sends signals through second messengers to affect cellular processes
193
What are the three small MW ionotropic neurotransmitters? (And what receptors do they activate?
1. Acetylcholine (ACH) —> nicotinic ionotropic receptors
2. Glutamate—> AMPA, Kainate and NMDA receptors
3. GABA —> GABAA receptors
194
What are the four types of small molecular weight metabotropic neurotransmitters? (And what receptors do they activate?)
1. ACh—> muscarinic
2. Glutamate—> mGlu
3. GABA—> GABA B
4. Dopamine and related biogenic amines (lots)
195
What are 5 examples of the high molecular weight metabotropic neurotransmitters?
```
1. Neuropeptides
A. Substance P
B. Oxytocin
C. Vasopressin
D. Angiotensin II
```
196
What is nicotine toxins’s 1. Origin, 2. Target, and 3. Symptoms?
Origin: tobacco plant
Target: activates ACh receptors
Symptoms: nausea, vomiting, mental convulsions
197
What is muscarine toxin’s 1. Origin, 2. Target, 3. Symptoms?
Origin: red mushroom
Target: activated ACh receptors
Symptoms: Nausea, vomiting, mental confusion
198
What is curare toxin’s 1. Origin, 2. Target, 3. Symptoms?
Origin: arrowhead poison from a plant
Target: block nicotinic ACh receptors
Symptoms: paralysis
199
What is picrotoxin’s 1. Origin, 2. Target, 3. Symptoms?
Origin: fish berries
Target: blocks GABA A receptors
Symptoms: seizures
200
What is tetrodotoxin’s 1. Origin, 2. Target, 3. Symptoms?
Origin: puffer fish and salamanders
Target: Blocks NA+ channels (except for in California garter snake who have mutations that the toxins can’t fit in the receptor)
Symptoms: paralysis
201
What are the 5 alkaloid toxins
Nicotine, muscarine, curare, picrotoxin and tetrodotoxin
202
What are the four peptide toxins?
Neurotoxin (scorpions), apamin (bees), alpha-bungarotoxin (snakes), conotoxin cocktail (conus)
203
What is the neurotoxin’s 1. Origin, 2. Target, 3. Symptoms?
Origin: scorpions
Target: Na+ channels (remain in the active state and can’t inactivate)
Symptoms: pain and decreased coordination
204
What is apamin toxin’s 1. Origin, 2. Target, 3. Symptoms?
Origin: Bees
Target: block leak K+ channels (SK Channels)
Causes the sensory neuron to approach threshold at rest
Symptoms: Pain
205
What is alpha-bungarotoxin’s 1. Origin, 2. Target, 3. Symptoms?
Origin: snakes
Target: blocks nicotinic ACh receptors- prevents ACh from opening post-synaptic ion channels
Symptoms: paralysis
206
What is conotoxin’s 1. Origin, 2. Target, 3. Symptoms?
Origins: cocktail of chemicals from conus
Target: Blocks Ca2+ channels, Na+ channels, K+ channels, ACh receptors and there is NO antidote
Symptoms: paralysis or immediate death
207
What are the two types of enzyme toxins?
Botulinum (Botox) and tetanus (responsible for lock jaw)
208
How does botulinum (Botox) function?
It cleaves presynaptic vesicle SNARE proteins, inhibits ACh release and causes paralysis
209
How does tetanus function to give you lock jaw?
It cleaves synaptobrevin, inhibits release of glycine and GABA, and causes continuous muscle contraction because there’s no inhibition of motor neurons
210
What are loss-of-function mutations?
Mutations that inactivates a gene or prevents/destroys protein from being produced. They’re generally recessive (you can get by with one copy) but lethal if homozygous
211
What are gain-of-function mutations?
A mutation that results in a new functional ability of a protein, and is normally dominant. Examples are epilepsy and HKPP (or 1,000 genes that when mutated with a GOF mutation will cause autism)
212
What receptor does Xanax and other benzodiazepines activated and what is its function?
It targets GABA receptors, and it facilitates the opening of GABAA channels—> used to treat anxiety, seizures and muscle spasms.
213
What does Prozac target and what is its function?
It targets serotonin (by being derived from tryptophan)—> used to treat depression and create feelings of wellbeing. It’s a reuptake inhibitor, allowing more serotonin to remain in the cleft
214
What do monoamine oxidase (MAO) inhibitors target and what is their function?
Targets dopamine, which comes from the amino acid tyrosine. Prevents the breakdown of dopamine and is used to treat depression
215
What is NaV1.1’s function and what is its mutation?
General Na+ channel in the CNS- a loss-of-function mutation leads to epilepsy by inhibiting transition from open to closed, and delaying repolarization.
216
What is NaV1.4 and what is its mutation?
It’s a skeletal muscle Na+ channel.
1. Causes Hyperkalemia (too much potassium outside the cell leading to depolarization
2. A Gain of function mutation causes Hyperkalemic Periodic Paralysis (HKPP), Which causes sodium channels to leak open, raising the resting potential of the cell
217
What is a potassium channel mutation?
Benign Familial Neonatal Convulsions (BFNC)
One subunit of the K+ channel mutated and whole channel struggles—> epilepsy disorder in young adulthood that children grow out of as they get older
Some K+ channels function as homotetramers, others as heterotetramers
