Exam 1 Deck 1 Flashcards
1
Q
How many specialized cell types are there in the brain?
A
Four. Five if you count ependymal cells.
Neurons
Astrocytes
Oligodendroglia
Microglia
(Ependymal Cells)
2
Q
What is the embryonic origin of neurons?
A
Ectoderm
3
Q
What are the functional unit of the CNS?
A
neurons
4
Q
Do neurons regenerate?
A
CNS neurons do not regenerate much (limited examples)
PNS neurons regenerate to a much greater degree.
5
Q
What is the function of glial cells?
A
They buffer and control the communication that comes into the neurons.
Maintain the microenvironment around the neuron.
Include:
Astrocytes
Oligodendroglia
Microglia
Ependymal Cells
6
Q
What are some functions of astrocytes?
A
Provide structure
Metabolic support
Maintain ion balance
Supply glutamate
Maintain BBB
7
Q
Which glial cells supply glutamate to neurons?
A
Astrocytes
8
Q
Which glial cells maintain the chemical mileu around neurons and provide support for the neuron?
A
Astrocytes
9
Q
Which glial cells provide the myelin sheath for axons in CNS?
A
Oligodendroglia (oligodendrocytes)
They provide the sheath of multiple CNS axons
(analagous to Schwann cells in PNS)
10
Q
What is the embryonic origin of astrocytes?
A
Ectoderm
11
Q
What is the embryologic origin of oligodendroglia
A
Ectoderm
12
Q
What is the embryological origin of microglia?
A
Mesoderm
13
Q
What is the main function of microglia?
A
Act as resident macrophages of brain and spinal cord
Activated in the case of damage and phagocytose foreign matter and apoptotic neurons
Make cytokines and neurotoxins
14
Q
Which glial cells are responsible for macrophage function in the spinal cord and brain?
A
microglia
15
Q
Which cells help maintain the blood-brain barrier (BBB)?
A
Endothelial cells lining the capillary wall (have TIGHT JUNCTIONS unlike other capillary endothelial cells)
Astrocytes with their foot processes
Basement membrane of capillaries
16
Q
What does the blood brai barrier do?
A
Prevents the passage of large molecules from blood into interstitial fluid of CNS
17
Q
What is the point of the blood-CSF barrier?
A
Prevents large molecules from passing from blood to CSF
18
Q
How is the blood-CSF barrier maintained?
A
By tight junctions between epithelial cells of the choroid plexus
19
Q
What does the choroid plexus do?
A
Lines the ventricles and produces CSF
Tight junctions between cells help maintain the blood-CSF barrier
20
Q
How long can a neuron last (on average) in an anoxic environment?
A
5-7 minutes
21
Q
Which cells are most sensitive to anoxia?
A
Neurons (specifically the cell body, or soma)
22
Q
Which cells are least sensitive to anoxia?
A
Blood vessels
23
Q
What is the order of sensitivity of anoxia (most to least)?
A
Nerve cells (soma then axon)
Myelin and oligodendroglial cells
Astrocytes
Microglia
Blood vessels
24
Q
What are two responses of brain neurons to injury?
A
Eosinophilic degeneration
Axonal reaction
25
What occurs durin eosinophilic degeneration?
Perikaryal cytoplasm becomes eosinophilic (pink) due to mitochondrial condensation
Nucleus becomes pyknotic (dark and shrunken)
Irreversible
4-6 hours after injury?
26
Which brain neuron response to injury is reversible?
Axonal Reaction
Eosinophilic degeneration is irreversible
27
Which brain neuron response to injury is irreversible?
Eosinophilic degeneration
Axonal reaction is reversible
28
What occurs during the axonal reaction of brain neuron injury?
Secondary nerve cell change, following damage ot axon
Swelling and rounding of cell body
Central fragmentation and the disappearance of Nissl substance (central chromatolysis)
Migration of nucleus to periphery.
Reversible if axonal integrity is restored.
29
What is unique about the brain in the response to injury that involves scarring?
NOT fibrous (no fibroblasts nor collagen deposition)
Instead, a glial scar forms comprised of reactive astrocytes.
30
What are the steps in the formation of a glial scar?
Astrocytosis - proliferation of astrocytes
Formation of reactive astrocytes - swelling of cytoplasm, fine processes are visible (star-like)
Gliosis - laying down of the scar (glial fibers coalesce made of glial fibrillary acidic protein, GFAP)
31
What occurs during astrocytosis?
Proliferation of astrocytes
Step 1 in the process of glial scar formation
32
What are reactive astrocytes?
Swollen, eosinophilic astrocytes with fine processes that contain glial fibers (looks star-like)
Step 2 in formation of glial scars
33
What occurs durin Gliosis?
Glial fibers coalesce and form the glial scar
Scar is made of glial fibrillary acidic protein (GFAP)
34
What is GFAP?
Glial fibrillary acidic protein
Makes up glial scars when coalesced
35
What makes up a glial scar?
Coalesced glial fibers made up of GFAP
36
What is the role of microglial cells in the brain response to injury?
Proliferate and accumulate within 5 days
Encircle degenerating neurons and form clusters around necrotic brain tissue (microglial nodules)
Activated microglial cells differentiate into macrophages (same function as in rest of body)
37
What are microglial nodules?
Clusters of microglia that encircle degenerating neurons and necrotic brain tissue
38
What is vasogenic edema?
Failure of tight junctions and astrocytic processes of BBB
Allows fluid and protein into cerebral parenchymal extracellular space
39
Which type of brain edema is responsive to steroids and osmotic therapy?
Vasogenic edema
Caused by failure of tight junctions and astrocytic processes of BBB
40
What is cytotoxic edema?
Derangement in cellular metabolism causes failure of ATP-dependent transport (Na, Ca)
Intracellular retention of Na, water follows
Astrocytes, capillary endothelial cells, neurons all SWELL
BBB in tact
41
Which type of brain edema is not responsive to steroids or osmotic agents?
Cytotoxic edema
BBB intact - caused by cellular metabolic failure (retention of Na, water follows)
42
When do you see vasogenic edema?
Tumors
Brain abscesses
Trauma
Inflammation
Hypertension
43
When do you see cytotoxic edema?
Ischemia
Hypoxia
Asphyxia
Intoxication
44
What is the Monroe-Kellie Doctrine?
Idea that the skull has a fixed volume and must accomodate variable volumes of brain, blood and CSF
Blood and CSF can be shunted to an extent, but beyond it, changes in either volume will result in increase in intracranial pressure
Cerebral Perfusion Pressure : CPP
Mean Arterial Pressure : MAP
Intracranial Pressure : ICP
CPP = MAP - ICP
45
What are symptoms of increased intracranial pressure?
Headache
Nausea
Vomiting
Bradychardia
Hypertension
Loss of consciousness
Papilledema
46
What is neuronal plasticity?
The change or adaptation of neuronal function and structure with activity/experience
The brain may not gain or lose many neurons, but as signals are transmitted, the neurons change over time. So the same stimulus is essentially acting on a 'different' neuron the second time.
47
Which type of signaling is portrayed in a "Classical" synapse?
Axo-dendritic synapse (Glutamatergic excitatory)
48
What type of synapse is glutamate involved in?
Axo-spinous (Axo-dendritic)
Classical
49
What type of synapse is GABA and the monoamines involved in?
Axo-dendritic
50
How are most signals between neurons transmitted?
Chemically via neurotransmitters and neuromodulators
Only a very small percentage are transmitted via electric signals where the two neurons share ion channels.
51
What are the seven steps of synaptic transmission?
1. Nerve impulse (action potential) invades presynaptic nerve terminal.
2. Activation of Ca2+ channels and entry of Ca2+ into nerve terminal.
3. Ca2+ triggers neurotransmitter release via exocytosis.
4. Released neurotransmitter activates pre- and postsynaptic receptors.
5. Receptor activation regulates channels to yield postsynaptic currents.
6. Released neurotransmitter is removed from synapse.
7. Vesicles involved in exocytosis are recaptured by endocytosis.
52
What are the steps in vesicular transport and recycling?
Docking to the active zone
Priming in an ATP-mediated manner
Fusion mediated by increased intracellular calcium levels
Clathrin-mediated endocytosis
Recycling and vesicular neurotransmitter transport (acidified on the inside to aid in travel towards synaptic cleft)
53
Why are vesicles acidified on the inside?
To aid in moving down the length of the axon of a neuron (charge)
54
What mediates vesicular endocytosis of vesicles in neurons?
Clathrin
55
What types of changes occur in the post-synaptic neuron that are responsible for plasticity?
Activation of second messengers causes transient adaptations, but the plasticity is introduced when these messengers affect transcription factors
This alters target gene expression which can alter the long-term function of neurons
56
What are the amino acid neurotransmitters?
Glutamate
GABA (gamma- aminobutyric acid)
Glycine
57
What are the monoamine neurotransmitters?
dopamine
norepinephrine (noradrenalin)
epinephrine (adrenalin)
serotonin
melatonin (only in pineal gland)
acetylcholine
histamine
58
What are the nucleoside neurotransmitters
adenosine
ATP
59
What are the lipid-derived neurotransmitters?
Anandamine
2-AG
60
What is a gas neurotransmitter?
Nitric Oxide (NO)
61
What type of neurotransmitter is Glutamate?
Amino Acid
62
What type of neurotransmitter is GABA?
Amino Acid
63
What type of neurotransmitter is Glycine?
Amino Acid
64
What type of neurotransmitter is dopamine?
monoamine
65
What type of neurotransmitter is norepinephrine?
monoamine
66
What type of neurotransmitter is epinephrine?
monoamine
67
What type of neurotransmitter is serotonin?
monoamine
68
What type of neurotransmitter is melatonin?
monoamine
69
What type of neurotransmitter is acetylcholine?
monoamine
70
What type of neurotransmitter is histamine?
monoamine
71
What type of neurotransmitter is adenosine?
nucleoside
72
What type of neurotransmitter is ATP?
nucleoside
73
What type of neurotransmitter is anandamide?
lipid-derived
74
What type of neurotransmitter is 2-AG?
lipid-derived
75
What type of neurotransmitter is Nitric Oxide?
gas
76
What types of receptors are referred to as ionotropic?
Ligand-gated channels
77
What kind of receptors are referred to as metabotropic?
G protein-coupled receptors (GPCRs)
78
Which neurotransmitter is the major excitatory neurotransmitter in the brain?
Glutamate
79
What does glutamate signal through?
Ligand gated Na (and sometimes Ca) channels - AMPA, NMDA, Kainate (rapid neurotransmission)
GPCRs - mGluR1-8 (autoreceptor, modulatory)
80
Where is glutamate found?
ubiquitous
Only a small fraction is packaged into vesicles to act as a neurotransmitter
(krebs cycle and metabolism use glutamate)
81
What role do astrocytes play in glutamatergic neurotransmission?
Regulatory, sequester glutamate and modify it to glutamine via glutamine synthetase
Help provide a glutamate-glutamine shunt to buffer glutamate levels, protecting neurons from excitotoxicity which can lead to death.
82
What are the catecholamines?
Dopamine
Norepinephrine
Epinephrine
83
What are the indolamines?
Serotonin
Melatonin
84
How do ionotropic receptors work?
Neurotransmitter binds to site on multi-subunit ion channel.
Binding opens the channel, allowing ion flow in or out of neuron.
This creates a rapid postsynaptic current.
Glutamate, ACh, serotonin, and nucleosides activate Na (and Ca) channels - excitatory
GABA, glycine activate Cl channels - inhibitory
85
How do metabotropic receptors work?
Neurotransmitter binds to site on single polypeptide protein.
Binding triggers conformational change in G proteins.
Released subunites then either directly or indirectly regulate ion channels
Gi -\> activate K channels or inhibit Ca channels.
Also have second messengers.
86
How do neurotrophic factors transmit signals?
Bind to plasma receptors that leads (directly or indirectly) to protein tyrosine kinase activation.
87
How do steroid hormones work in neurotransmission?
Hormones diffuse passively into cytoplasm, where they bind to the steroid receptor
This can translocate to nucleus and act on DNA as a transcription factor.
88
What are autoreceptors?
They are receptors expressed on nerve terminals that respond to the neurotransmitter released by those terminals.
They are linked to Gi, such that activation inhibits the nerve terminal, blocking further neurotransmitter release.
NEGATIVE FEEDBACK
89
How do neurons prevent a continual release of neurotransmitter from their axonic terminal?
Autoreceptors provide negative feedback that inhibits neurotransmitter release
90
What packages glutamate into vesicles?
Vesicular glutamate transporters (VGluT)
91
What is the major inhibitory neurotransmitter in the brain and spinal cord?
GABA
92
What big-picture role does GABA play in the body?
Regulates the level of consciousness
Too much : sleep, coma or dead
Too little: seizures, dead
93
What does GABA signal through?
ionotropic receptors (Cl): GABA-A =\> fast inhibitory signaling
metabotropic receptors: GABA-B, GABA-C =\> slower modulatory inhibiting signaling
autoreceptors (GABA-B)
94
What are the autoreceptors for glutamate?
metabotropic (mGluR)
95
What are the autoreceptors for GABA?
GABA-B (metabotropic)
96
How is GABA synthesized?
Glutamate to GABA in a single step via Glutamic Acid Decarboxylase (GAD)
Degraded by GABA transaminase
97
How is GABA degraded?
GABA transaminase
98
What sort of drugs act on glutamatergic synapses?
psychotomimetic (psychosis inducing) drugs
e.g. phencyclidine and ketamine act on NMDA as antagonists
99
What sorts of drugs act on GABAergic synapses?
anticonvulsant drugs and sedative-hypnotics
anticonvulsants promote GABAergic transmission (increase GABA synthesis or blocking reuptake)
sedative-hypnotics promote GABA-A receptor function (benzodiazepines, barbituates)
Drugs that block GABA-A receptors induce seizures
100
Where does glycine act primarily?
Spinal cord
101
What is the function of glycine?
Major inhibitory neurotransmitter in the spinal cord
Along with GABA
102
What effect do blockers of glycine receptors have?
Convulsants (induce seizures)
e.g. strychnine
103
What is the receptor for glycine signaling?
Trychnine-sensitive glycine receptor (ionotropic)
This gates Cl
104
What is the effect of strychnine?
Induces seizures.
Blocks the strychnine-sensitive glycine receptor (which would normally be inhibitory)
105
What is the secondary role of glycine in neurotransmission?
Acting as a co-agonist for the NMDA glutamate receptor.
Binds to a novel site on the receptor (not responsive to strychnine), and enhances the activity of glutamate on the receptor.
106
What are all catecholamines derived from?
Tyrosine
107
Tyrosine is an important precursor to which neurotransmitters?
Catecholamines
108
In general, what type of effect to monoamines exert ?
Modulatory - widespread projections and most neurons are responsive to them, even though few cells signal through them. They can be seen as increasing or decreasing the gain on the effect of other signals
In contrast, glutamate and GABA act in a more point-to-point fashion that exert more binary responses
109
Broadly speaking, what is the target of most drugs that act on the nervous system?
Monoamine neurotransmitter systems
110
What is the rate limiting **enzyme** in the series of reactions that produces catecholamines from tyrosine?
Tyrosine hydroxylase (TH)
111
What is the rate-limiting **substrate** in the series of reactions that produces catecholamines from tyrosine?
L-DOPA (Dihydroxyphenylalanine)
112
What is the reaction that directly generates dopamine?
DOPA decarboxylase (also known as aromatic amino acid decarboxylase) converts L-DOPA to dopamine.
113
What is the precursor to dopamine?
L-DOPA.
DOPA decarboxylase (also known as aromatic amino acid decarboxylase) converts L-DOPA to dopamine.
114
What is the reaction that produces norepinephrine?
Dopamine beta-hydroxylase (DBH) converts dopamine to norepinephrine
occurs in noradrenergic neurons
115
What is the precursor to norepinephrine?
dopamine
116
What is the reaction that produces epinephrine?
phenylethanolamine-N-methytransferase (PNMT) converts norepinephrine to epinephrine
117
what is the precursor to epinephrine?
norepinephrine
118
What enzymes degrade the catecholamines?
monoamine oxidases (MAOs) and catechol-O-methyltransferase (COMT)
119
What is the function of monoamine oxidases (MAOs) and catechol-O-methyltransferase (COMT)?
Degrade catecholamines.
120
What packages catecholamines into vesicles for transport?
VMAT (vesicular monoamine transporter)
Packages dopamine, norepinephrine, epinephrine
Also does serotonin
121
What are the three nuclei of dopaminergic neurons in the brain?
Substantia nigra (SN)
Ventral tegmental area (VTA)
Arcuate nucleus
SN and VTA are in the midbrain, arcuate nucleus is in the hypothalamus
122
Where is the ventral tegmental area located and what does it contain?
midbrain
dopaminergic neuron nucleus
123
Where is the substantia nigra located and what does it contain?
Midbrain
Dopaminergic neuron nucleus
124
Where is the arcuate nucleus located and what does it contain?
hypothalamus
Dopaminergic neuron nucleus
125
Where do the substantia nigra dopamine neurons innervate (project to)?
The neostriatum (caudate-putamen).
This forms the nigrostriatal dopamien pathway.
126
What is the nigrostriatal dopamine pathway?
Between substantia nigra and striatum
127
Where do the ventral tegmental area dopamine neurons innervate (project to)?
Many regions in the forebrain (including nucleus accumbens, hippocampus, amygdala, and prefrontal cortex)
Crucial for reward, motivation, emotional memory, and executive planning
128
What is the mesocorticolimbic dopaminergic neuron pathway?
Projections from the Ventral tegmental area to various areas in the forebrain
129
Where do the arcuate nucleus dopamine neurons innervate (project to)?
Anterior pituitary
Inhibits prolactin secretion
130
What is the tuberoinfundibular dopaminergic neuron pathway?
From the arcuate nucleus to anterior pituitary
Dopamine inhibits prolactin secretion at the anterior pituitary
131
What type of receptors are dopamine receptors?
GPCRs
132
Which dopamine receptors are coupled to Gs?
D1 and D5 (D1 class)
133
Which dopamine receptors are coupled to Gi?
D2, D3, D4 (D2 class)
134
Which dopamine receptors serve as autoreceptors?
D2 class (D2, D3, D4)
135
Which neurons are lost in Parkinson's Disease?
subsgtantia nigra dopamine neurons
136
What is a mainstay of treatment for Parkinsons and why?
L-DOPA (dopamine precursor), since it promotes dopamine synthesis
D-2 dopamine receptor agonists (D-2 also found post-synaptically)
Parkinson's is caused by a selective loss of substantia nigra dopamine neurons
Muscarinic cholinergic antagonists are used to treat Parkinson’s disease, based on the role of cholinergic interneurons in regulating striatal function
137
Where to psychostimulant drugs work?
Dopaminergic synapses by maintaining high levels of dopamine in the synapse
Cocaine inhibits the dopamine transport (blocks reuptake)
Amphetamine 'reverses' it (causing release of dopamine from the transporter)
138
Where do most antipsychotic drugs work?
At dopaminergic synapses, blocking the D2 Receptors (either antagonists or partial agonists)
139
Which types of drugs block D2 receptors (antagonists or partial agonists)?
Antipsychotics
140
What is the main nucleus of noradrenergic (norepinephrine) neurons in the brain?
Locus Ceruleus in the pons
141
Where is the locus ceruleus located?
the pons
142
What is the locus ceruleus?
The main noradrenergic (norepinephrine) nucleus in the brain
143
Where do the noradrenergic neurons from the locus ceruleus project to?
Most of the forebrain
Therefore, most neurons in the forebrain are responsive to noradrenergic signals, even though only very few neurons produce norepinephrine (noradrenaline)
144
How does norepinephrine (noradrenergic) signaling occur?
Atypical
Released and travels long distances to exert its effect on many neurons
145
What does noradrenergic signaling control?
Vigilance and attention
Cenral control over ANS
Responses to stress and emotional behavior
Post-ganglionic sympathetic signaling
146
What type of receptors are noradrenergic receptors?
All are GPCRs
Beta (Gs)
Alpha-1 (Gq)
Alpha-2 (Gi) : autoreceptor
147
What type of drugs act on norepinephrine receptors?
Many drugs for cardiovascular disease and upper respiratory function
148
What type of receptors do many cardiovascular disease and upper respiratory funciton drugs target?
Noradrenergic receptors
149
What type of drugs inhibit norepinephrine reuptake?
Antidepressants
Used to treat chronic pain and ADHD
150
How are MAO inhibitors used?
Antidepressants
Block the breakdown of monoamines (norepinephrine)
151
What amino acid are serotonin and melatonin derived from?
Tryptophan
152
What is 5HT?
5-hydroxytryptamine
Serotonin
153
What is the other name for serotonin?
5HT (5-hydroxytryptamine)
154
What is the rate-limiting enzyme in the production of serotonin?
Tryptophan hydroxylase (TPH)
155
What is the rate-limiting substrate in the production of serotonin?
5-hydroxytryptophan
156
What enzyme converts 5-hydroxytryptophan to 5-hydroxytryptamine (serotonin)
aromatic amino acid decarboxylase (AADC)
157
How is melatonin synthesized?
From Tryptophan, through Serotonin, via an intermediate
158
How are serotonin and melatonin degraded?
monoamine oxidase (MAO)
159
What enzyme packages serotonin and melatonin into synaptic vesicles?
VMAT (Vesicular monoamine transporter)
160
Where are the serotinergic neuron nuclei located?
Brainstem
Most important is the dorsal raphe nucleus
161
Which is the most important serotonergic nucleus in the brain?
The dorsal raphe nucleus
162
What is the dorsal raphe nucleus?
Most important serotonergic nucleus in the brain
163
Where does the dorsal raphe nucleus project to?
All over the brain and spinal cord
Exert broad modulatory effects
164
What responses do serotonergic neurons regulate?
Stress responses and emotional behavior
Eating and weight control
Cicadian rhythms and sleep-wake cycles
165
How many serotonin receptors are there?
14
5HT-3 is the only ionotropic (Ligand-gated)
The rest (5HT-1, 5HT-2, 5HT-4-7) are metabotropic (GPCR)
166
Which serotonin receptors are metabotropic?
5HT-1 (Gi)
5HT-2 (Gq)
5HT-4-7(Gs)
167
Which serotonin receptors are ionotropic (ligand gated)?
5HT-3
168
Which serotonin receptors function as autoreceptors?
5HT-1 (coupled to Gi)
169
How do most antidepressant drugs work?
Inhibit serotonin reuptake (SSRIs and SNRIs)
Also MAO inhibitors
170
What function do drugs that inhibit serotonin reuptake have?
Antidepressants
171
Where do new antipsychotic drugs and hallucinogenic drugs act?
5HT-2A receptors
antipsychotics block (they also act on D2 receptors)
hallucinogens are partial agonists
172
What drugs act on the 5HT-2A receptors?
New antipsychotics (which also act on D2 receptors) act as antagonists (block)
Hallucinogens act as partial agonists
173
What are 5HT-2C receptors involved in?
Feeding responses
Agonists decrease feeding
Antagonists promote feeding and can result in obesity
(at hypothalamus)
174
Where do new anti-migrane drugs (triptans) work?
5HT-1D as agonists
175
What are triptans?
New anti-migrane drugs that act as 5HT-1D agonists
176
How is acetylcholine synthesized?
From choline in a single step via choline acetyltransferase
177
What enzyme makes acetylcholine from choline + Acetyl CoA?
Choline acetyltransferase
178
What enzyme breaks down acetylcholine?
Acetylcholinesterase
179
What enzyme packages acetylcholine into vesicles?
Vesicular acetylcholine transporter
180
Where is acetylcholinesterase located?
In the synapse
Breakes down ACh into Choline, which can be transported into neurons for recycling
181
Where are cholinergic neurons located in the brain?
Forebrain nuclei - medial septal nuclei + Nucleus basalis of Meynert
Brainstem nuclei - dorsolateral tegmentum in the pons
182
What is the medial septal nucleus?
One of the two forebrain cholinergic neuron nuclei
Also the nucleus basalis of Meynert
183
What is the nucleus basalis of Meynert?
Forebrain cholinergic neuron nucleus
Along with the medial septal nucleus
184
What is the dorsolateral tegmentum?
Brainstem cholinergic neuron nucleus, located in the pons
185
Where do the forebrain cholinergic neuron nuclei project to?
Hippocampus and other forebrain structures
Important for learning, memory and cognition
186
Where do the brainstem cholinergic neuron nuclei project to?
Widely - important for sleep-wake cycles
(this is the dorsolateral tegmentum)
187
Where are cholinergic interneurons located?
Striatum
Important role in modulating striatal-dependent motor function
188
Which type of neurons modulate striatal-dependent motor function?
cholinergic interneurons
189
What is the role of acetylcholine outside of the brain?
ANS: All preganglionic sympathetic and parasympathetic, and most postganglionic parasympathetic
Somatic motor system: NMJ is cholinergic (with nicotinic receptors)
190
What receptors does acetylcholine act on?
Nicotinic (ligand-gated; ionotropic)
Muscarinic (GPCR; metabotropic) : autoreceptors
191
What are nicotinic receptors?
ligand-gated (ionotropic) acetylcholine receptors
Nicotinic receptors flux Na+ and Ca2+, thereby mediating excitatory postsynaptic currents
192
What type of currents do nicotinic receptors mediate?
Nicotinic receptors flux Na+ and Ca2+, thereby mediating excitatory postsynaptic currents
193
What does nicotine do?
Strong partial agonist at central cholinergic receptors
Actiavtes VTA (ventral tegmental area) dopamine neurons to promote reward
194
Why are muscarinic cholinergic antagonists are used to treat Parkinson’s disease?
Because cholinergic interneurons in regulating striatal function
195
What are acetylcholinesterase inhibitors used to treat?
Dementia due to their role in hippocampal circuits
196
What is the mechanism of the cardiovascular and related side effects (constipation, dry mouth, blurred vision) of many drugs?
Muscarinic receptor antagonism
197
How does botulinum toxin (botox) work?
Blocks ACh release
198
How does curare work?
blocks neuromuscular junctions NMJs
nicotinic receptor antagonist - causes paralysis
199
How is histamine synthesized?
In a single step from histidine, via histidine decarboxylase
200
Where are histaminergic neurons located?
In the tuberomammillary nucleus in the hypothalamus
201
Where is the tuberomammillary nucleus located?
Hypothalamus
202
What is the tuberomammillary nucleus?
Nucleus of histaminergic neurons in the hypothalamus
203
Where does the tuberomammillary nucleus project to?
Widespread throughout the brain
204
What is the primary effect of histamine in the brain?
To regulate alertness and sleep-wake cycles (sedation)
205
What type of receptors does histamine act on?
Metabotropic (GPCRS)
H1 is the most important in the brain (antihistamines)
H2 inhibits stomach acid
H3 is an autoreceptor
206
What is the H1 receptor involved in?
Histaminergic neurotransmission in the brain (and elsewhere)
Major player in the brain
207
What is the H2 receptor involved in?
Stomach acid secretion in the stomach
208
What is the H3 receptor involved in?
Autoreceptor for histamine in the brain.
209
What is a major difference between peptide neurotransmitters and small molecule neurotransmitters?
Peptides must be synthesized in the cell body and transported to terminals.
They are also degraded enzymatically once released, which is irreversible
As a result, they represent an energetically expensive process
210
What types of receptors do peptide neurotransmitters act on?
GPCRs - metabotropic
211
What is the general scheme of peptide neurotransmitter synthesis?
Prepropeptide gene - encodes prepropeptide mRNA - produces prepropeptide in the ER - proteolytically processed into propetide - further processed into mature peptide
212
What is POMC
Proopiomelanocortin - a small peptide that can be proteolytically cleaved into a variety of different neurotransmitter signals
213
What are some functions of peptide neurotransmitters?
Hypothalamic releasing and inhibitory factors (CRH, TRH, GnRH, GHRH, somatostatin)
Feedign and gut-brain peptides (Neuropeptide Y, alpha-MSH, cholecystokinin, glucagon-related peptide, vasoactive intestinal polypeptide)
Tachykinins (e.g. substance P) - involved in nociception (pain control)
214
What is meant by co-transmission?
The notion that neurons that signal through peptides also signal through small molecules such as glutamate or monoamines
215
What is another name for orexin?
hypocretin
216
What is hypocretin?
orexin
217
What type of neurotransmitter is orexin?
Peptide
218
Where are orexinergic neurons located?
In the lateral hypothalamus
219
Where do orexinergic neurons from the lateral hypothalamus project to?
Widespread in the brain
220
What type of receptors are orexin receptors?
GPCR - metabotropic
221
What are the orexin receptors?
OX1 and OX2 (metabotropic GPCR)
222
What is the role of orexin?
Promotes wakefulness
Orexinergic neurons project strongly to the histaminergic tuberomammillary nucleus and to the brainstem cholinergic nuclei, both critical for control over sleep vs. wakefulness
223
Where do orexonergic neurons project strongly?
Orexinergic neurons project strongly to the **histaminergic tuberomammillary** **nucleus** and to the **brainstem cholinergic nuclei**, both critical for control over sleep vs. wakefulness
224
What occurs in human narcolepsy?
Death of orexinergic neurons (autoimmune?)
Characterized by intrusive REM sleep during wakefulness
225
What occurs when there is death of orexinergic neurons?
One thing that may occur is narcolepsy
226
Apart from wakefulness, what are other functions that orexin modulates?
alertness
mood
reward
motivation
likely via strong projections to monoaminergic nuclei
227
What are the three main types of opioid peptides?
Enkephalines (preproenkephalin)
Endorphins (prePOMC: preproopiomelanocortin)
Dynorphin (preprodynorphin)
228
What type of neurotransmitter are the enkephalins?
opioid peptide
229
What type of neurotransmitter are the endorphins?
opioid peptide
230
What type of neurotransmitter is dynorphin?
opioid peptide
231
Where is enkephalin synthesized?
Brain and spinal cord
232
Where is dynorphins synthesized?
brain and spinal cord
233
Where are endorphins synthesized?
hypothalamus
234
Where do enkephalins act on?
mu and delta opioid receptors
Promote reward, positive mood, analgesia, sedation
235
Where do endorphins act on?
mu and delta opioid receptors
promote reward, positive mood, analgesia, sedation
236
Where do dynorphins act on?
kappa opioid receptors
promote analgesia and sedation,
Induce negative mood state
237
Which opioid peptides induce a negative mood state?
Dynorphins
238
Which opioid receptors induce a positive mood state?
Enkephalins and endorphins
239
What receptors do opiate drugs generally act on?
mu opioid receptors as agonists
No difference between prescribed and illicit opiates, just pharmacokinetics
240
What role do nucleosides play as neurotransmitters?
Modulatory
Likely to be ubiquitous
241
Which nucleoside neurotransmitter is packaged in most vesicles?
ATP
242
What type of receptors do nucleosides signal through?
Both ligand-gated (ionotropic) and GPCRs (metabotropic)
243
What is the role of adenosine?
Regulation of sleep
Adenosine accumulates during wakefulness to promote sleep
Sleep redues adenosine levels
244
What is the effect of sleep on adenosine levels?
Reduces them
Adenosine accumulates during wakefulness and promotes sleep
245
What is an example of an adenosine receptor antagonist?
Caffeine
Promotes wakefulness
246
What type of drug is caffeine?
Adenosine receptor antagonist
Promotes wakefulness
247
What are lipid-derived neurotransmitters derived from?
arachidonic acid
Anandamide and 2-arachidonoylglycerol (2-AG)
known as endocannabinoids
248
What are the endocannabinoids?
anandamide and 2-AG
249
What are the receptors for the endocannabinoids?
Cannabinoid receptors CB1 and CB2 (GPCRs)
250
What are the effects of cannabinoid drugs mediated through?
Activation of CB1 receptors
251
What is marijuana?
Cannabinoid drug that activates CB1 receptors
252
What is the effect of endocannabinoids?
Regulate perception, appetite, nociception, reward, and level of consciousness
253
How do endocannabinoids transmit signal?
Endocannabinoids are synthesized postsynaptically in response to Ca2+ influx, and are then released (presumably by passive diffusion) into the synapse where they act on CB1 receptors located on nearby nerve terminals to regulate neurotransmitter release
Retrograde
254
Which neurotransmitters function in a retrograde manner?
Endocannabinoids
Nitric Oxide
Endocannabinoids are synthesized postsynaptically in response to Ca2+ influx, and are then released (presumably by passive diffusion) into the synapse where they act on CB1 receptors located on nearby nerve terminals to regulate neurotransmitter release
NO is synthesized by nitric oxide synthase (activated by Ca2+)
255
What triggers endocannabinoid synthesis and release?
Endocannabinoids are synthesized postsynaptically in response to Ca2+ influx, and are then released (presumably by passive diffusion) into the synapse where they act on CB1 receptors located on nearby nerve terminals to regulate neurotransmitter release
256
What triggers Nitric Oxide synthesis and release?
Synthesized post-synaptically in response to Ca2+ influx by nitric oxide synthase, a Ca2+ activated enzyme
Then it diffuses into the synapse, where it enters nerve terminals passively
257
What is the effect of Nitric Oxide?
Once diffused into nerve cells (retrograde), it activates many enzymes, such as guanylyl cyclase, which synthesizes cyclic GMP (cGMP), modulating the release of neurotransmitters by these neurons
258
What is the main role of Nitric Oxide?
Neuromodulatory in the brain like endocannabinoids
Excitatory feedback
259
What is the resting potential of a neuron?
-70mV
260
What ion mostly determines a neuron's membrane potential?
K+
261
What ions contribute to the resting potential of a neuron?
K+ (most important) E = -75mV
Na: E = +40mV
Cl: E = -80mV
262
At rest, which ion channels are mostly open and closed?
Open: K+ channels
Closed: Na+ and Cl- channels
263
What is the ionic basis of an action potential?
Depolarization induces the opening of Na+ channels (faster) and K+ channels (slower)
This induces further depolarization until the Na+ channels close and inactivate (refractory period)
K+ channels then bring the potential back down again
264
Where do local analgesics act?
Block voltage-gated Na+ channels
265
How is tonic (pacemaker) action potential firing mediated?
Often mediated by the presence of HCN channels, which are activated (gated) by cyclic AMP
266
What is the axon hillock?
Triggering point of an action potential (base of the axon)
267
Why do action potentials only travel in one direction?
Refractory period prevents activation again
268
What types of ion channels are located at the nerve terminals?
Voltage-gated Ca2+ channels
Open when nerve terminal is depolarized, which allows entry of calcium, and the release of neurotransmitters
269
Why do muscle units reliably contract in response to every presynaptic action potential?
1) there is a very high probability of acetylcholine release in response to each action potential
2) the muscle endplate—through extensive folding—provides a large surface area of nicotinic acetylcholine receptors.
270
What is Myasthenia Gravis?
autoimmune disorder caused by auto-antibodies directed against the nicotinic cholinergic receptor or another postsynaptic protein
Characterized by muscle weakness, often around the eye (ptosis, blurred vision)
Test by treating with cholinesterase inhibitor to releive symptoms
271
How can you diagnose Myasthenia Gravis?
Treatment with cholinesterase inhibitor - instant releif of symptoms
272
What is Eaton-Lambert syndrome?
Condition similar to Myasthenia Gravis caused by autoantibodies to presynaptic terminal (often voltage-gated Ca2+ channels)
Muscle weakness of limbs
273
What is the difference between Myasthenia Gravis and Eaton-Lambert syndrome?
MG affects postsynaptic terminal (autoantibodies to nAChR) while EL affects the pre-synaptic terminal
274
What is the activity of the Na+/K+ ATPase (Na+/K+ Pump)?
Pumps 3 Na+ out of the cell and 2 K+ into the cell
restores the ionic gradient and the resting potential in the neuron
Electrogenic
275
What is the action of cardiac glycosides?
Inhibit the Na+/K+ pump and increase strength of cardiac muscle contraction
e.g. ouabain, digitalis
276
What are some cardiac glycosides?
ouabain
digitalis
Inhibit the Na+/K+pump and increase strength of cardiac muscle contraction
277
What is the action of ouabain, digitalis?
Inhibit Na+/K+ pump and increase strength of cardiac muscle contraction
278
What is the relationship between speed of electrical conduction (speed of action potential propagation) and axon caliber?
Directly proportional - myelination makes it so that you don't need HUGE axons for fast transmission
279
What is the difference in conductance between myelinated and non-myelinated axons?
Myelinated axons are wrapped in myelin sheath which greatly increases speed of action potential propagation
Non-myelinated are slow, since the propagation is continuous and every segment must be depolarized to threshold
280
What is present at Nodes of Ranvier?
NO myelin
Nodes are enriched in voltage-gated Na+ channels bordered by regions rich in K+ channels.
281
Which cell types form myelin sheaths?
Oligodendrocytes
282
What type of conduction is enabled by myelin?
saltatory - jumping from one node of Ranvier to the next
283
Which disease is caused by autoimmune destruction of myelin sheaths?
Multiple Sclerosis (MS)
Any part of the CNS can be affected - highly variable symptoms
Can lead to the destruction of underlying axon (excitotoxicity)
284
What is MS?
Multiple Sclerosis
Autoimmune destruction of myelin sheaths
Affects any part of the CNS - highly variable symptoms
Can lead to the destruction of underlying axon - excitotoxicity
285
How is pain perceived?
In two waves:
Aδ fibers are larger and heavily myelinated - conduct quickly
C fibers are smaller and not myelinated - conduct slower
286
What are Aδ fibers?
Pain sensation (nociception) fibers that transmit quickly - thick and heavily myelinated
287
What are C fibers
Pain sensation (nociception) fibers that transmit signals slowly - thin and non-myelinated
288
Can a single synaptic potential initiate an action potential?
No
an action potential might require dozens or hundreds of synaptic potentials that summate in time or space
289
What is an EPSP or EPSC?
Excitatory postsynaptic potential or excitatory postsynaptic current
Need to be summed in space or time in order to trigger an action potential
290
What are large EPSP (EPSC)'s mediated by?
glutamate
more specifically, by glutamate acting on ionotropic glutamate receptors (mostly AMPA receptors)
291
What are large, fast IPSP (IPSC)'s mediated by?
GABA (and glycine in spinal cord)
mainly by acting on ionotropic GABA receptors (GABA-A receptors) (glycine acts on ionotropic glycine receptors)
292
What determines whether or not a neuron will display an action potential?
Dozens (hundreds) of EPSPs and IPSPs summate at a single neuron to determine whether that neuron will display an action potential
293
What is the difference between metabotropic and ionotropic (GPCR and ligand-gated) channel signaling with respect to EPSP's and IPSPs?
Most G protein-coupled receptors give rise to smaller and slower EPSPs or IPSPs. This is why the neurotransmitters that mediate these responses are sometimes referred to as neuromodulators. These neuromodulatory actions modulate the ability of ionotropic receptors to trigger an action potential
294
What is an EEG?
Electroencephalogram
Surface electrodes detect potentials from surface areas of brain
Can show potentials that originate from synchronous activity at populations of synapses
Big oscillations are not normal - show seizure activity
295
What is post-tetanic potentiation (PTP)?
An example of short-term plasticity
Response to a signle stimulus is enhanced after a tetanus (period of high frequency stimulation)
296
What is tetanus?
A period of high frequency stimulation
297
What is paired-pulse facilitation (PPF)?
When a single stimulus occurs soon after an earlier one, a larger postsynaptic potential is produced (Excess Ca2+ is still in the terminal)
298
What are two short-term forms of neural plasticity
Post-tetanic potentiation (PTP)
Paired-pulse facilitation (PPF)
299
How is short-term potentiation acheived?
By the buildup of Ca2+ in a pre-synaptic terminal or the depletion of vesicles
300
What is NMDAR-dependent LTP?
NMDA receptor dependent long-term potentiation
Can be brought about by tetanus which induces high levels of Ca2+ into post-synaptic spines. This activates CaMKII, which phosphorylates AMPA receptors and drives their insertion to the synapse
Also accompanied by changes in gene expression
Other non NMDAR-dependent mechanisms also present
301
What is NMDAR dependent LTD?
NMDA receptor dependent long-term depression
Can be brought about by low-frequency stimulation which induces low Ca2+ entry, and activates Calcineurin, which removes AMPA receptors from the synaptic terminal.
Also accompanied by changes in gene expression
Other forms exist too
302
What changes occur in plasticity?
Both in function and in morphology
E.g. neuronal spine morphology changes over time.
303
How can you distinguish between an axon and a dendrite?
Axons keep their diameter throughout their length
Dendrites thin out as you get further away from the soma
304
How do axons and dendrites differ in their microtubule arrangement?
In axons, MTs are aligned
In dendrites, MTs are not
305
Bipolar neurons are important in what functions?
Sensory
Vision, audition, balance
306
Where are unipolar neurons important?
Dorsal Root Ganglia
307
What is a bouton?
The swelling at an axon terminal
308
What is a telodendron?
The entire array of terminals for one axonal process
309
What are multipolar neurons?
Prototypical neurons
They have 3-5 primary dendrites emanating from the cell body, and an axon emerging from the axon hillock. They are found throughout the CNS.
310
What are bipolar neurons?
Have a single process, with the cell body located directly along the course of that process. The distal extension is the dendrite, and the proximal part of the process (directed toward the CNS) is the axon.
Primarily involved in sensation
311
What are unipolar neurons?
Have a single process that extends proximally and distally from a short segment of the process that connects it to the cell body.
Although both parts of the process of a unipolar neurons are properly called "neurites", the distal and proximal parts of the process are often referred to as the dendrite and the axon, respectively.
312
What are pyramidal cells?
Pyramidal cells vary in size, but have a stereotypical shape: a pear- shaped soma, several dendrites (called basal dendrites) emerging from the base of the soma, a large and highly branched dendrite emerging from the apex of the soma (called the apical dendrite), and an axon that issues from the base of the cell body.
Most have spiny dendrites
Involved in signal processing and integration
313
What are granule cells?
Granule cells are smaller, and are often star-shaped (stellate) because the dendritic tree radiates out in all directions from the soma.
Granule cells provide much of the local (regional) information processing.
314
What are projection cells?
Neurons with long axons are projection cells
315
What are interneurons?
Neurons with short axons are called interneurons or local circuit neurons
Many are inhibitory
316
What are amacrine cells?
Axon-less neurons are called amacrine cells
Found mostly in the retina and olfactory bulb (rare)
317
What is special about en passant synpases?
They occur partway along the axon as it extends
318
Describe a motor end plate (neuromuscular junction, NMJ).
Consists of enlarged terminal containing synaptic vesicles, junctional folds, an enlarged synaptic cleft, and the muscle sole plate. It is covered by oligodendrocyte cytoplasm and basal lamina.
319
Where are fibrous astrocytes found?
White matter
320
What type of astrocytes are found in white matter?
Fibrous
321
Where are protoplasmic astrocytes found?
Gray matter
322
What type of astrocytes are found in gray matter?
Protoplasmic
323
What are the two components of the brain?
Cerebrum
Brainstem
324
What are the three components of the brainstem?
Medulla oblongata
Midbrain
Pons/Cerebellum
325
Where do the rostral-caudal, anterior-posterior, dorsal-ventral, superior-inferior axes refer to?
326
What is the axial/horizontal plane?
327
What is the coronal/frontal plane?
328
What is the (para/mid)saggital plane?
329
What are the eight bones of the cranium?
Frontal
Parietal (2)
Occipital
Temporal (2)
Sphenoid
Ethmoid
330
What are the four sutures of the cranium?
Coronal
Lamboid
Saggital
Temporal/parietal (squamosal)
331
What are the three main compartments in the base of the skull?
Anterior Fossa
Middle Fossa
Posterior Fossa
332
Which bones does the coronal suture join?
Frontal + 2 parietal
333
What bones does the lamboid suture join?
2 Parietal + occipital
334
What bones does the sagittal suture join?
The two parietal bones
335
What bones does the temporal/parietal (squamosal) suture join?
The temporal and parietal bones
336
Where does the spinal cord pass through the skull?
Foramen magnum
337
How many vertebrae are there?
~30
7 Cervical
12 Thoracic
5 Lumbar
5 Sacral
1 Fused coccygeal (or 4 independent - giving you 33 total)
338
How many pairs of spinal nerves are there?
31
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
339
Where does the cauda equina start?
L1/L2 - important for lumbar punctures
340
What are the three layers of the meninges?
Pia mater
Arachnoid mater
Dura mater
(From closest to outermost)
341
What are the four dural folds (reflections)?
falx cerebri (between the two cerebral hemispheres)
tentorium cerebelli (overlying the cerebellum)
falx cerebelli (between the two cerebellar hemispheres)
diaphragma sellae (forming a roof over the pituitary fossa, perforated by the pituitary stalk)
342
What is the falx cerebri?
A dural fold that seperates the two hemispheres of the brain
343
What is the tentorium cerebelli
Dural fold that overlies the cerebellum
344
What is the diaphragma sellae?
Dural fold that overlies the pituitary
345
What is the falx cerebelli?
A dural fold that separates the hemispheres of the cerebellum
346
How many layers of dura are there in the cerebrum?
2
outer lines the skull and serves as the periosteum (rich in vasculature)
inner follows the arachnoid in most places except in the sinuses
347
What is a dural sinus?
Area where the outer and inner layer of the dura are not connected (allows for venous blood and other structures to course through (particularly in the cavernous sinus
348
What is the superior longitudinal sinus?
Prominent dural sinus present at the sagittal midline, at the junction of the dural cap and the falx cerebri
349
What is the coccygeal ligament comprised of?
Dura
Runs from the end of the spinal cord and attaches at the coccyx
350
What are subarachnoid cisterns?
Areas in the brainstem, spinal cord and brain where the space between the pia mater and the arachnoid mater is particularly large and is filled with CSF
Quadrigeminal cistern
Interpeduncular cistern
Pontine cistern
Cisterna Magna
Lumbar cistern
351
What is significant about the lumbar cistern?
It is a great place to extract CSF since the conus medullaris terminates rostral to it
352
Where are arachnoid villi (granulations) most common?
along the interhemispheric fissure, associated with the superior longitudinal sinus
353
What are arachnoid trabecula?
Parts of the arachnoid mater that extend down and connect to the pia mater - forming columns that give the subarachnoid space it's shape
354
How many layers does the pia have?
2
The inner one, the intima pia, adheres to the underlying nervous tissue and forms the outer wall of perivascular spaces where blood vessels enter and exit the CNS. It is avascular.
The more superficial layer, the epipia, is continuous with the arachnoid trabeculae. It is well developed in the spinal cord, but not in brain. It anchors the spinal cord to the vertebrae
355
What is the intima pia?
The inner layer of the pia mater, that reliably follows the spinal cord
356
What is the epipia?
The outer layer of the pia mater that anchors the spinal cord to the vertebrae via dentate ligaments
357
What is a dentate ligament?
Outer layer of pia mater (epipia) that extends out and anchors the spinal cord laterally to the vertebrae
358
What is the filum terminale compsed of?
Epipia
359
What are differences in the meninges between the cerebrum and the spinal cord?
1. In the cerebrum, there are two distinct layers of dura. In the spinal cord, while there are trace cellular elements of a periosteal (outer) dura, for all intents and functional purposes there is only one dural layer.
2. The cerebrum has essentially a single pial layer whereas the spinal cord has two distinct pial layers.
3. The blood vessels of the spinal cord are in the epipial layer. Cerebral blood vessels lie on the surface of the intima pia, within the subarachnoid space.
4. Although arachnoid villi have been described in the spinal region, they are far less common than in the cerebrum.
360
Identify the central sulcus
361
Identify the lateral sulcus (Sylvian fissure) 
362
Identify the frontal lobe 
363
Identify the temporal lobe 
364
Identify the parietal lobe.
365
Identify the occipital lobe
366
Identify the precental sulcus
367
Identify the precental gyrus. What does it control? 
Primary MOTOR cortex
368
Identify the superior frontal sulcus
369
Identify the inferior frontal sulcus 
370
Identify the 1st (superior) frontal gyrus
371
Identify the 2nd (middle) frontal gyrus.
372
Identify the 3rd (inferior) frontal gyrus.
373
Identify Broca's Area. What is it's function?
Speech production
Of note - it is asymmetric; stronger on left (in most people)
374
Identify the frontal pole
375
Identify the postcentral gyrus. What is its function?
Primary SOMATOSENSORY cortex
376
Identify the postcentral sulcus
377
Identify the intraparietal sulcus
378
Identify the superior parietal lobule
379
Identify the inferior parietal lobule. What is its function? 
Primary vestibular cortex (synthesis of information, conscious perception of balance)
380
Identify the occipital pole. What function is associated with it?
Vision
381
Where is the interhemispheric fissure?
Between the two hemispheres of the brian.
382
Identify the superior temporal sulcus
383
Identify the superior temporal gyrus
384
Identify Heschl's Gyri. What is its function?
Primary auditory cortex
385
Identify Wernicke's Area. What is it's function?
Speech recognition/comprehension
386
Identify the temporal pole
387
Identify the middle temporal sulcus/gyrus
388
Identify the inferior temporal sulcus/gyrus
389
Where is the insular lobe? What is it's function? 
Primary GUSTATORY cortex
390
Identify the frontal pole (and occipital pole).
391
Identify the central sulcus
392
Identify the olfactory bulb
393
Identify the olfactory tract
394
Identify the olfactory stria
395
Identify the anterior perforated space (substance).
396
Identify the olfactory fissure.
397
Identify the gyrus rectus.
398
Identify the orbital gyrus.
399
Identify the primary olfactory cortex.
400
Identify the optic nerve, chiasm, tract.
401
Identify the pituitary (infundibulum) and its stalk.
402
Identify the median eminence
403
Identify the tuber cinereum.
404
Identify the mammillary bodies
405
Identify the uncus
406
Identify the parahippocampal gyrus
407
Identify the collateral sulcus
408
Identify the rhinal fissure
409
Identify the corpus callosum.
410
Identify the rostrum of the corpus callosum.
411
Identify the genu of the corpus callosum
412
Identify the body of the corpus callosum
413
Identify the splenium of the corpus callosum
414
Identify the callosal sulcus
415
Identify the cingulate gyrus.
416
Identify the cingulate sulcus
417
Identify the paracentral lobule.
418
Identify the parieto-occipital sulcus.
419
Identify the calcarine fissure.
420
Identify where the primary visual cortex is.
421
Identify the limbic lobe.
422
Identify the isthmus (retrosplenial cortex)
423
Identify the subcallosal gyri of the limbic lobe 
424
Identify the thalamus.
425
Identify the epithalamus
426
Identify the subthalamus.
427
Identify the hypothalamus.
428
Identify the midbrain
429
Identify the Pons/cerebellum.
430
Identify the medulla.
431
Identify the cerebral peduncle.
432
Identify the pyramid
433
Identify the olfactory nerve. 
Cranial Nerve I
434
Identify the optic nerve.
Cranial Nerve II
435
Identify the oculomotor nerve.
Cranial Nerve III
436
Identify the trochlear nerve.
Cranial Nerve IV
437
Identify the Trigeminal Nerve
Cranial Nerve V
438
Identify the Abducens Nerve
439
Identify the Facial Nerve.
Cranial Nerve VII
440
Identify the vestibulo-cochlear nerve.
Cranial Nerve VIII
441
Identify the glossopharyngeal nerve
Cranial Nerve IX
442
Identify the Vagus Nerve.
Cranial Nerve X
443
Identify the Spinal Accessory Nerve.
Cranial Nerve XI
444
Identify the Hypoglossal nerve.
Cranial Nerve XII
445
Identify the superior cerebellar peduncle
446
Identify the middle cerebellar peduncle
447
Identify the inferior cerebellar peduncle
448
Identify the pyramidal decussation. Why is it important?
It marks the transition from the brainstem to the spinal cord
449
Identify the posteromedian fissure
#1 in the diagram
450
Identify the posterolateral fissure.
2 in the diagram
451
Identify the sensory fibers.
#3 in the diagram
452
Identify the DRGs.
#8 in the diagram
453
Identify the sensory tracts.
#5 in the diagram
454
Identify the anterolateral fissure.
1 in the diagram
455
Identify the motor fibers.
#2 in the figure
456
Identify the DRGs
#3 in the figure
457
Identify the sensory fibers
4 in the figure
458
What is a ventricle?
A continuous fluid-filled sac (of CSF)
459
Identify the lateral ventricle
460
Identify the anterior horn of the left ventricle
#2
461
Identify the body of the lateral ventricle
#1
462
Identify the inferior (temporal) horn of the lateral ventricle 
#8
463
Identify the posterior (occiptal) horn of the lateral ventricles 
#11
464
Identify the atrium of the lateral ventricle
465
Identifyt he interventricular foramen of Monro
#4
466
Identify the third ventricle
#5
467
Identify the optic recess 
#6
468
Identify the infundibular recess
#7
469
Identify the habenular recess 
#9
470
Identify the pineal recess
#10
471
Identify the interthalamic adhesion
#3
472
Identify the cerebral aqueduct of Sylvius (the aqueduct)
#12
473
Identify the fourth ventricle
#14
474
Identify the foramen of Magendie
#13 (**M**idline **M**agendie)
475
Identify the foramina of Luschka
#15 (**L**ateral **L**uschka)
476
Identify the central canal
#16
477
Identify the obex
478
Identify the lateral ventricle
479
Identify the interventricular foramina of Monro 
480
Identify the third ventricle
481
Identify the optic recess
482
Identify the infundibular recess
483
Identify the habendular recess
484
Identify the pineal recess
485
Identify the cerebral aqueduct of Sylvius
486
Identify the fourth ventricle
487
Identify the central canal
488
Identify the lateral ventricle
489
Identify the Third Ventricle
490
Identify the foramen of Monro 
491
Identify the aqueduct
492
Identify the fouth ventricle
