Exam 1 Deck 1 Flashcards
How many specialized cell types are there in the brain?
Four. Five if you count ependymal cells.
Neurons
Astrocytes
Oligodendroglia
Microglia
(Ependymal Cells)
What is the embryonic origin of neurons?
Ectoderm
What are the functional unit of the CNS?
neurons
Do neurons regenerate?
CNS neurons do not regenerate much (limited examples)
PNS neurons regenerate to a much greater degree.
What is the function of glial cells?
They buffer and control the communication that comes into the neurons.
Maintain the microenvironment around the neuron.
Include:
Astrocytes
Oligodendroglia
Microglia
Ependymal Cells
What are some functions of astrocytes?
Provide structure
Metabolic support
Maintain ion balance
Supply glutamate
Maintain BBB
Which glial cells supply glutamate to neurons?
Astrocytes
Which glial cells maintain the chemical mileu around neurons and provide support for the neuron?
Astrocytes
Which glial cells provide the myelin sheath for axons in CNS?
Oligodendroglia (oligodendrocytes)
They provide the sheath of multiple CNS axons
(analagous to Schwann cells in PNS)
What is the embryonic origin of astrocytes?
Ectoderm
What is the embryologic origin of oligodendroglia
Ectoderm
What is the embryological origin of microglia?
Mesoderm
What is the main function of microglia?
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
Which glial cells are responsible for macrophage function in the spinal cord and brain?
microglia
Which cells help maintain the blood-brain barrier (BBB)?
Endothelial cells lining the capillary wall (have TIGHT JUNCTIONS unlike other capillary endothelial cells)
Astrocytes with their foot processes
Basement membrane of capillaries
What does the blood brai barrier do?
Prevents the passage of large molecules from blood into interstitial fluid of CNS
What is the point of the blood-CSF barrier?
Prevents large molecules from passing from blood to CSF
How is the blood-CSF barrier maintained?
By tight junctions between epithelial cells of the choroid plexus
What does the choroid plexus do?
Lines the ventricles and produces CSF
Tight junctions between cells help maintain the blood-CSF barrier
How long can a neuron last (on average) in an anoxic environment?
5-7 minutes
Which cells are most sensitive to anoxia?
Neurons (specifically the cell body, or soma)
Which cells are least sensitive to anoxia?
Blood vessels
What is the order of sensitivity of anoxia (most to least)?
Nerve cells (soma then axon)
Myelin and oligodendroglial cells
Astrocytes
Microglia
Blood vessels
What are two responses of brain neurons to injury?
Eosinophilic degeneration
Axonal reaction
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?
Which brain neuron response to injury is reversible?
Axonal Reaction
Eosinophilic degeneration is irreversible
Which brain neuron response to injury is irreversible?
Eosinophilic degeneration
Axonal reaction is reversible
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.
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.
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)
What occurs during astrocytosis?
Proliferation of astrocytes
Step 1 in the process of glial scar formation
What are reactive astrocytes?
Swollen, eosinophilic astrocytes with fine processes that contain glial fibers (looks star-like)
Step 2 in formation of glial scars
What occurs durin Gliosis?
Glial fibers coalesce and form the glial scar
Scar is made of glial fibrillary acidic protein (GFAP)
What is GFAP?
Glial fibrillary acidic protein
Makes up glial scars when coalesced
What makes up a glial scar?
Coalesced glial fibers made up of GFAP
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)
What are microglial nodules?
Clusters of microglia that encircle degenerating neurons and necrotic brain tissue
What is vasogenic edema?
Failure of tight junctions and astrocytic processes of BBB
Allows fluid and protein into cerebral parenchymal extracellular space
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
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
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)
When do you see vasogenic edema?
Tumors
Brain abscesses
Trauma
Inflammation
Hypertension
When do you see cytotoxic edema?
Ischemia
Hypoxia
Asphyxia
Intoxication
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
What are symptoms of increased intracranial pressure?
Headache
Nausea
Vomiting
Bradychardia
Hypertension
Loss of consciousness
Papilledema
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.
Which type of signaling is portrayed in a “Classical” synapse?
Axo-dendritic synapse (Glutamatergic excitatory)
What type of synapse is glutamate involved in?
Axo-spinous (Axo-dendritic)
Classical
What type of synapse is GABA and the monoamines involved in?
Axo-dendritic
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.
What are the seven steps of synaptic transmission?
- Nerve impulse (action potential) invades presynaptic nerve terminal.
- Activation of Ca2+ channels and entry of Ca2+ into nerve terminal.
- Ca2+ triggers neurotransmitter release via exocytosis.
- Released neurotransmitter activates pre- and postsynaptic receptors.
- Receptor activation regulates channels to yield postsynaptic currents.
- Released neurotransmitter is removed from synapse.
- Vesicles involved in exocytosis are recaptured by endocytosis.
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)
Why are vesicles acidified on the inside?
To aid in moving down the length of the axon of a neuron (charge)
What mediates vesicular endocytosis of vesicles in neurons?
Clathrin
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
What are the amino acid neurotransmitters?
Glutamate
GABA (gamma- aminobutyric acid)
Glycine
What are the monoamine neurotransmitters?
dopamine
norepinephrine (noradrenalin)
epinephrine (adrenalin)
serotonin
melatonin (only in pineal gland)
acetylcholine
histamine
What are the nucleoside neurotransmitters
adenosine
ATP
What are the lipid-derived neurotransmitters?
Anandamine
2-AG
What is a gas neurotransmitter?
Nitric Oxide (NO)
What type of neurotransmitter is Glutamate?
Amino Acid
What type of neurotransmitter is GABA?
Amino Acid
What type of neurotransmitter is Glycine?
Amino Acid
What type of neurotransmitter is dopamine?
monoamine
What type of neurotransmitter is norepinephrine?
monoamine
What type of neurotransmitter is epinephrine?
monoamine
What type of neurotransmitter is serotonin?
monoamine
What type of neurotransmitter is melatonin?
monoamine
What type of neurotransmitter is acetylcholine?
monoamine
What type of neurotransmitter is histamine?
monoamine
What type of neurotransmitter is adenosine?
nucleoside
What type of neurotransmitter is ATP?
nucleoside
What type of neurotransmitter is anandamide?
lipid-derived
What type of neurotransmitter is 2-AG?
lipid-derived
What type of neurotransmitter is Nitric Oxide?
gas
What types of receptors are referred to as ionotropic?
Ligand-gated channels
What kind of receptors are referred to as metabotropic?
G protein-coupled receptors (GPCRs)
Which neurotransmitter is the major excitatory neurotransmitter in the brain?
Glutamate
What does glutamate signal through?
Ligand gated Na (and sometimes Ca) channels - AMPA, NMDA, Kainate (rapid neurotransmission)
GPCRs - mGluR1-8 (autoreceptor, modulatory)
Where is glutamate found?
ubiquitous
Only a small fraction is packaged into vesicles to act as a neurotransmitter
(krebs cycle and metabolism use glutamate)
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.
What are the catecholamines?
Dopamine
Norepinephrine
Epinephrine
What are the indolamines?
Serotonin
Melatonin
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
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.
How do neurotrophic factors transmit signals?
Bind to plasma receptors that leads (directly or indirectly) to protein tyrosine kinase activation.
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.
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
How do neurons prevent a continual release of neurotransmitter from their axonic terminal?
Autoreceptors provide negative feedback that inhibits neurotransmitter release
What packages glutamate into vesicles?
Vesicular glutamate transporters (VGluT)
What is the major inhibitory neurotransmitter in the brain and spinal cord?
GABA
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
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)
What are the autoreceptors for glutamate?
metabotropic (mGluR)
What are the autoreceptors for GABA?
GABA-B (metabotropic)
How is GABA synthesized?
Glutamate to GABA in a single step via Glutamic Acid Decarboxylase (GAD)
Degraded by GABA transaminase
How is GABA degraded?
GABA transaminase
What sort of drugs act on glutamatergic synapses?
psychotomimetic (psychosis inducing) drugs
e.g. phencyclidine and ketamine act on NMDA as antagonists
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
Where does glycine act primarily?
Spinal cord
What is the function of glycine?
Major inhibitory neurotransmitter in the spinal cord
Along with GABA
What effect do blockers of glycine receptors have?
Convulsants (induce seizures)
e.g. strychnine
What is the receptor for glycine signaling?
Trychnine-sensitive glycine receptor (ionotropic)
This gates Cl
What is the effect of strychnine?
Induces seizures.
Blocks the strychnine-sensitive glycine receptor (which would normally be inhibitory)
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.
What are all catecholamines derived from?
Tyrosine
Tyrosine is an important precursor to which neurotransmitters?
Catecholamines
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
Broadly speaking, what is the target of most drugs that act on the nervous system?
Monoamine neurotransmitter systems
What is the rate limiting enzyme in the series of reactions that produces catecholamines from tyrosine?
Tyrosine hydroxylase (TH)
What is the rate-limiting substrate in the series of reactions that produces catecholamines from tyrosine?
L-DOPA (Dihydroxyphenylalanine)
What is the reaction that directly generates dopamine?
DOPA decarboxylase (also known as aromatic amino acid decarboxylase) converts L-DOPA to dopamine.
What is the precursor to dopamine?
L-DOPA.
DOPA decarboxylase (also known as aromatic amino acid decarboxylase) converts L-DOPA to dopamine.
What is the reaction that produces norepinephrine?
Dopamine beta-hydroxylase (DBH) converts dopamine to norepinephrine
occurs in noradrenergic neurons
What is the precursor to norepinephrine?
dopamine
What is the reaction that produces epinephrine?
phenylethanolamine-N-methytransferase (PNMT) converts norepinephrine to epinephrine
what is the precursor to epinephrine?
norepinephrine
What enzymes degrade the catecholamines?
monoamine oxidases (MAOs) and catechol-O-methyltransferase (COMT)
What is the function of monoamine oxidases (MAOs) and catechol-O-methyltransferase (COMT)?
Degrade catecholamines.
What packages catecholamines into vesicles for transport?
VMAT (vesicular monoamine transporter)
Packages dopamine, norepinephrine, epinephrine
Also does serotonin
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
Where is the ventral tegmental area located and what does it contain?
midbrain
dopaminergic neuron nucleus
Where is the substantia nigra located and what does it contain?
Midbrain
Dopaminergic neuron nucleus
Where is the arcuate nucleus located and what does it contain?
hypothalamus
Dopaminergic neuron nucleus
Where do the substantia nigra dopamine neurons innervate (project to)?
The neostriatum (caudate-putamen).
This forms the nigrostriatal dopamien pathway.
What is the nigrostriatal dopamine pathway?
Between substantia nigra and striatum
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
What is the mesocorticolimbic dopaminergic neuron pathway?
Projections from the Ventral tegmental area to various areas in the forebrain
Where do the arcuate nucleus dopamine neurons innervate (project to)?
Anterior pituitary
Inhibits prolactin secretion
What is the tuberoinfundibular dopaminergic neuron pathway?
From the arcuate nucleus to anterior pituitary
Dopamine inhibits prolactin secretion at the anterior pituitary
What type of receptors are dopamine receptors?
GPCRs
Which dopamine receptors are coupled to Gs?
D1 and D5 (D1 class)
Which dopamine receptors are coupled to Gi?
D2, D3, D4 (D2 class)
Which dopamine receptors serve as autoreceptors?
D2 class (D2, D3, D4)
Which neurons are lost in Parkinson’s Disease?
subsgtantia nigra dopamine neurons
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
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)
Where do most antipsychotic drugs work?
At dopaminergic synapses, blocking the D2 Receptors (either antagonists or partial agonists)
Which types of drugs block D2 receptors (antagonists or partial agonists)?
Antipsychotics
What is the main nucleus of noradrenergic (norepinephrine) neurons in the brain?
Locus Ceruleus in the pons
Where is the locus ceruleus located?
the pons
What is the locus ceruleus?
The main noradrenergic (norepinephrine) nucleus in the brain
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)
How does norepinephrine (noradrenergic) signaling occur?
Atypical
Released and travels long distances to exert its effect on many neurons
What does noradrenergic signaling control?
Vigilance and attention
Cenral control over ANS
Responses to stress and emotional behavior
Post-ganglionic sympathetic signaling
What type of receptors are noradrenergic receptors?
All are GPCRs
Beta (Gs)
Alpha-1 (Gq)
Alpha-2 (Gi) : autoreceptor
What type of drugs act on norepinephrine receptors?
Many drugs for cardiovascular disease and upper respiratory function
What type of receptors do many cardiovascular disease and upper respiratory funciton drugs target?
Noradrenergic receptors
What type of drugs inhibit norepinephrine reuptake?
Antidepressants
Used to treat chronic pain and ADHD
How are MAO inhibitors used?
Antidepressants
Block the breakdown of monoamines (norepinephrine)
What amino acid are serotonin and melatonin derived from?
Tryptophan
What is 5HT?
5-hydroxytryptamine
Serotonin
What is the other name for serotonin?
5HT (5-hydroxytryptamine)
What is the rate-limiting enzyme in the production of serotonin?
Tryptophan hydroxylase (TPH)
What is the rate-limiting substrate in the production of serotonin?
5-hydroxytryptophan
What enzyme converts 5-hydroxytryptophan to 5-hydroxytryptamine (serotonin)
aromatic amino acid decarboxylase (AADC)
How is melatonin synthesized?
From Tryptophan, through Serotonin, via an intermediate
How are serotonin and melatonin degraded?
monoamine oxidase (MAO)
What enzyme packages serotonin and melatonin into synaptic vesicles?
VMAT (Vesicular monoamine transporter)
Where are the serotinergic neuron nuclei located?
Brainstem
Most important is the dorsal raphe nucleus
Which is the most important serotonergic nucleus in the brain?
The dorsal raphe nucleus
What is the dorsal raphe nucleus?
Most important serotonergic nucleus in the brain
Where does the dorsal raphe nucleus project to?
All over the brain and spinal cord
Exert broad modulatory effects
What responses do serotonergic neurons regulate?
Stress responses and emotional behavior
Eating and weight control
Cicadian rhythms and sleep-wake cycles
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)
Which serotonin receptors are metabotropic?
5HT-1 (Gi)
5HT-2 (Gq)
5HT-4-7(Gs)
Which serotonin receptors are ionotropic (ligand gated)?
5HT-3
Which serotonin receptors function as autoreceptors?
5HT-1 (coupled to Gi)
How do most antidepressant drugs work?
Inhibit serotonin reuptake (SSRIs and SNRIs)
Also MAO inhibitors
What function do drugs that inhibit serotonin reuptake have?
Antidepressants
Where do new antipsychotic drugs and hallucinogenic drugs act?
5HT-2A receptors
antipsychotics block (they also act on D2 receptors)
hallucinogens are partial agonists
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
What are 5HT-2C receptors involved in?
Feeding responses
Agonists decrease feeding
Antagonists promote feeding and can result in obesity
(at hypothalamus)
Where do new anti-migrane drugs (triptans) work?
5HT-1D as agonists
What are triptans?
New anti-migrane drugs that act as 5HT-1D agonists
How is acetylcholine synthesized?
From choline in a single step via choline acetyltransferase
What enzyme makes acetylcholine from choline + Acetyl CoA?
Choline acetyltransferase
What enzyme breaks down acetylcholine?
Acetylcholinesterase
What enzyme packages acetylcholine into vesicles?
Vesicular acetylcholine transporter
Where is acetylcholinesterase located?
In the synapse
Breakes down ACh into Choline, which can be transported into neurons for recycling
Where are cholinergic neurons located in the brain?
Forebrain nuclei - medial septal nuclei + Nucleus basalis of Meynert
Brainstem nuclei - dorsolateral tegmentum in the pons
What is the medial septal nucleus?
One of the two forebrain cholinergic neuron nuclei
Also the nucleus basalis of Meynert
What is the nucleus basalis of Meynert?
Forebrain cholinergic neuron nucleus
Along with the medial septal nucleus
What is the dorsolateral tegmentum?
Brainstem cholinergic neuron nucleus, located in the pons
Where do the forebrain cholinergic neuron nuclei project to?
Hippocampus and other forebrain structures
Important for learning, memory and cognition
Where do the brainstem cholinergic neuron nuclei project to?
Widely - important for sleep-wake cycles
(this is the dorsolateral tegmentum)
Where are cholinergic interneurons located?
Striatum
Important role in modulating striatal-dependent motor function
Which type of neurons modulate striatal-dependent motor function?
cholinergic interneurons
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)
What receptors does acetylcholine act on?
Nicotinic (ligand-gated; ionotropic)
Muscarinic (GPCR; metabotropic) : autoreceptors
What are nicotinic receptors?
ligand-gated (ionotropic) acetylcholine receptors
Nicotinic receptors flux Na+ and Ca2+, thereby mediating excitatory postsynaptic currents
What type of currents do nicotinic receptors mediate?
Nicotinic receptors flux Na+ and Ca2+, thereby mediating excitatory postsynaptic currents
What does nicotine do?
Strong partial agonist at central cholinergic receptors
Actiavtes VTA (ventral tegmental area) dopamine neurons to promote reward
Why are muscarinic cholinergic antagonists are used to treat Parkinson’s disease?
Because cholinergic interneurons in regulating striatal function
What are acetylcholinesterase inhibitors used to treat?
Dementia due to their role in hippocampal circuits
What is the mechanism of the cardiovascular and related side effects (constipation, dry mouth, blurred vision) of many drugs?
Muscarinic receptor antagonism
How does botulinum toxin (botox) work?
Blocks ACh release
How does curare work?
blocks neuromuscular junctions NMJs
nicotinic receptor antagonist - causes paralysis
How is histamine synthesized?
In a single step from histidine, via histidine decarboxylase
Where are histaminergic neurons located?
In the tuberomammillary nucleus in the hypothalamus
Where is the tuberomammillary nucleus located?
Hypothalamus
What is the tuberomammillary nucleus?
Nucleus of histaminergic neurons in the hypothalamus
Where does the tuberomammillary nucleus project to?
Widespread throughout the brain
What is the primary effect of histamine in the brain?
To regulate alertness and sleep-wake cycles (sedation)
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
What is the H1 receptor involved in?
Histaminergic neurotransmission in the brain (and elsewhere)
Major player in the brain
What is the H2 receptor involved in?
Stomach acid secretion in the stomach
What is the H3 receptor involved in?
Autoreceptor for histamine in the brain.
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
What types of receptors do peptide neurotransmitters act on?
GPCRs - metabotropic
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
What is POMC
Proopiomelanocortin - a small peptide that can be proteolytically cleaved into a variety of different neurotransmitter signals
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)
What is meant by co-transmission?
The notion that neurons that signal through peptides also signal through small molecules such as glutamate or monoamines
What is another name for orexin?
hypocretin
What is hypocretin?
orexin
What type of neurotransmitter is orexin?
Peptide
Where are orexinergic neurons located?
In the lateral hypothalamus
Where do orexinergic neurons from the lateral hypothalamus project to?
Widespread in the brain
What type of receptors are orexin receptors?
GPCR - metabotropic
What are the orexin receptors?
OX1 and OX2 (metabotropic GPCR)
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
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
What occurs in human narcolepsy?
Death of orexinergic neurons (autoimmune?)
Characterized by intrusive REM sleep during wakefulness
What occurs when there is death of orexinergic neurons?
One thing that may occur is narcolepsy
Apart from wakefulness, what are other functions that orexin modulates?
alertness
mood
reward
motivation
likely via strong projections to monoaminergic nuclei
What are the three main types of opioid peptides?
Enkephalines (preproenkephalin)
Endorphins (prePOMC: preproopiomelanocortin)
Dynorphin (preprodynorphin)
What type of neurotransmitter are the enkephalins?
opioid peptide
What type of neurotransmitter are the endorphins?
opioid peptide
What type of neurotransmitter is dynorphin?
opioid peptide
Where is enkephalin synthesized?
Brain and spinal cord
Where is dynorphins synthesized?
brain and spinal cord
Where are endorphins synthesized?
hypothalamus
Where do enkephalins act on?
mu and delta opioid receptors
Promote reward, positive mood, analgesia, sedation
Where do endorphins act on?
mu and delta opioid receptors
promote reward, positive mood, analgesia, sedation
Where do dynorphins act on?
kappa opioid receptors
promote analgesia and sedation,
Induce negative mood state
Which opioid peptides induce a negative mood state?
Dynorphins
Which opioid receptors induce a positive mood state?
Enkephalins and endorphins
What receptors do opiate drugs generally act on?
mu opioid receptors as agonists
No difference between prescribed and illicit opiates, just pharmacokinetics
What role do nucleosides play as neurotransmitters?
Modulatory
Likely to be ubiquitous
Which nucleoside neurotransmitter is packaged in most vesicles?
ATP
What type of receptors do nucleosides signal through?
Both ligand-gated (ionotropic) and GPCRs (metabotropic)
What is the role of adenosine?
Regulation of sleep
Adenosine accumulates during wakefulness to promote sleep
Sleep redues adenosine levels
What is the effect of sleep on adenosine levels?
Reduces them
Adenosine accumulates during wakefulness and promotes sleep
What is an example of an adenosine receptor antagonist?
Caffeine
Promotes wakefulness
What type of drug is caffeine?
Adenosine receptor antagonist
Promotes wakefulness
What are lipid-derived neurotransmitters derived from?
arachidonic acid
Anandamide and 2-arachidonoylglycerol (2-AG)
known as endocannabinoids
What are the endocannabinoids?
anandamide and 2-AG
What are the receptors for the endocannabinoids?
Cannabinoid receptors CB1 and CB2 (GPCRs)
What are the effects of cannabinoid drugs mediated through?
Activation of CB1 receptors
What is marijuana?
Cannabinoid drug that activates CB1 receptors
What is the effect of endocannabinoids?
Regulate perception, appetite, nociception, reward, and level of consciousness
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
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+)
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
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
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
What is the main role of Nitric Oxide?
Neuromodulatory in the brain like endocannabinoids
Excitatory feedback
What is the resting potential of a neuron?
-70mV
What ion mostly determines a neuron’s membrane potential?
K+
What ions contribute to the resting potential of a neuron?
K+ (most important) E = -75mV
Na: E = +40mV
Cl: E = -80mV
At rest, which ion channels are mostly open and closed?
Open: K+ channels
Closed: Na+ and Cl- channels
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
Where do local analgesics act?
Block voltage-gated Na+ channels
How is tonic (pacemaker) action potential firing mediated?
Often mediated by the presence of HCN channels, which are activated (gated) by cyclic AMP
What is the axon hillock?
Triggering point of an action potential (base of the axon)
Why do action potentials only travel in one direction?
Refractory period prevents activation again
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
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.
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
How can you diagnose Myasthenia Gravis?
Treatment with cholinesterase inhibitor - instant releif of symptoms
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
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
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
What is the action of cardiac glycosides?
Inhibit the Na+/K+ pump and increase strength of cardiac muscle contraction
e.g. ouabain, digitalis
What are some cardiac glycosides?
ouabain
digitalis
Inhibit the Na+/K+pump and increase strength of cardiac muscle contraction
What is the action of ouabain, digitalis?
Inhibit Na+/K+ pump and increase strength of cardiac muscle contraction
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
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
What is present at Nodes of Ranvier?
NO myelin
Nodes are enriched in voltage-gated Na+ channels bordered by regions rich in K+ channels.
Which cell types form myelin sheaths?
Oligodendrocytes
What type of conduction is enabled by myelin?
saltatory - jumping from one node of Ranvier to the next
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)
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
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
What are Aδ fibers?
Pain sensation (nociception) fibers that transmit quickly - thick and heavily myelinated
What are C fibers
Pain sensation (nociception) fibers that transmit signals slowly - thin and non-myelinated
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
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
What are large EPSP (EPSC)’s mediated by?
glutamate
more specifically, by glutamate acting on ionotropic glutamate receptors (mostly AMPA receptors)
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)
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
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
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
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)
What is tetanus?
A period of high frequency stimulation
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)
What are two short-term forms of neural plasticity
Post-tetanic potentiation (PTP)
Paired-pulse facilitation (PPF)
How is short-term potentiation acheived?
By the buildup of Ca2+ in a pre-synaptic terminal or the depletion of vesicles
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
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
What changes occur in plasticity?
Both in function and in morphology
E.g. neuronal spine morphology changes over time.
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
How do axons and dendrites differ in their microtubule arrangement?
In axons, MTs are aligned
In dendrites, MTs are not
Bipolar neurons are important in what functions?
Sensory
Vision, audition, balance
Where are unipolar neurons important?
Dorsal Root Ganglia
What is a bouton?
The swelling at an axon terminal
What is a telodendron?
The entire array of terminals for one axonal process
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.
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
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.
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
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.
What are projection cells?
Neurons with long axons are projection cells
What are interneurons?
Neurons with short axons are called interneurons or local circuit neurons
Many are inhibitory
What are amacrine cells?
Axon-less neurons are called amacrine cells
Found mostly in the retina and olfactory bulb (rare)
What is special about en passant synpases?
They occur partway along the axon as it extends
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.
Where are fibrous astrocytes found?
White matter
What type of astrocytes are found in white matter?
Fibrous
Where are protoplasmic astrocytes found?
Gray matter
What type of astrocytes are found in gray matter?
Protoplasmic
What are the two components of the brain?
Cerebrum
Brainstem
What are the three components of the brainstem?
Medulla oblongata
Midbrain
Pons/Cerebellum
Where do the rostral-caudal, anterior-posterior, dorsal-ventral, superior-inferior axes refer to?
What is the axial/horizontal plane?
What is the coronal/frontal plane?
What is the (para/mid)saggital plane?
What are the eight bones of the cranium?
Frontal
Parietal (2)
Occipital
Temporal (2)
Sphenoid
Ethmoid
What are the four sutures of the cranium?
Coronal
Lamboid
Saggital
Temporal/parietal (squamosal)
What are the three main compartments in the base of the skull?
Anterior Fossa
Middle Fossa
Posterior Fossa
Which bones does the coronal suture join?
Frontal + 2 parietal
What bones does the lamboid suture join?
2 Parietal + occipital
What bones does the sagittal suture join?
The two parietal bones
What bones does the temporal/parietal (squamosal) suture join?
The temporal and parietal bones
Where does the spinal cord pass through the skull?
Foramen magnum
How many vertebrae are there?
~30
7 Cervical
12 Thoracic
5 Lumbar
5 Sacral
1 Fused coccygeal (or 4 independent - giving you 33 total)
How many pairs of spinal nerves are there?
31
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
Where does the cauda equina start?
L1/L2 - important for lumbar punctures
What are the three layers of the meninges?
Pia mater
Arachnoid mater
Dura mater
(From closest to outermost)
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)
What is the falx cerebri?
A dural fold that seperates the two hemispheres of the brain
What is the tentorium cerebelli
Dural fold that overlies the cerebellum
What is the diaphragma sellae?
Dural fold that overlies the pituitary
What is the falx cerebelli?
A dural fold that separates the hemispheres of the cerebellum
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
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
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
What is the coccygeal ligament comprised of?
Dura
Runs from the end of the spinal cord and attaches at the coccyx
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
What is significant about the lumbar cistern?
It is a great place to extract CSF since the conus medullaris terminates rostral to it
Where are arachnoid villi (granulations) most common?
along the interhemispheric fissure, associated with the superior longitudinal sinus
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
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
What is the intima pia?
The inner layer of the pia mater, that reliably follows the spinal cord
What is the epipia?
The outer layer of the pia mater that anchors the spinal cord to the vertebrae via dentate ligaments
What is a dentate ligament?
Outer layer of pia mater (epipia) that extends out and anchors the spinal cord laterally to the vertebrae
What is the filum terminale compsed of?
Epipia
What are differences in the meninges between the cerebrum and the spinal cord?
- 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.
- The cerebrum has essentially a single pial layer whereas the spinal cord has two distinct pial layers.
- 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.
- Although arachnoid villi have been described in the spinal region, they are far less common than in the cerebrum.
Identify the central sulcus
Identify the lateral sulcus (Sylvian fissure)
Identify the frontal lobe
Identify the temporal lobe
Identify the parietal lobe.
Identify the occipital lobe
Identify the precental sulcus
Identify the precental gyrus. What does it control?
Primary MOTOR cortex
Identify the superior frontal sulcus
Identify the inferior frontal sulcus
Identify the 1st (superior) frontal gyrus
Identify the 2nd (middle) frontal gyrus.
Identify the 3rd (inferior) frontal gyrus.
Identify Broca’s Area. What is it’s function?
Speech production
Of note - it is asymmetric; stronger on left (in most people)
Identify the frontal pole
Identify the postcentral gyrus. What is its function?
Primary SOMATOSENSORY cortex
Identify the postcentral sulcus
Identify the intraparietal sulcus
Identify the superior parietal lobule
Identify the inferior parietal lobule. What is its function?
Primary vestibular cortex (synthesis of information, conscious perception of balance)
Identify the occipital pole. What function is associated with it?
Vision
Where is the interhemispheric fissure?
Between the two hemispheres of the brian.
Identify the superior temporal sulcus
Identify the superior temporal gyrus
Identify Heschl’s Gyri. What is its function?
Primary auditory cortex
Identify Wernicke’s Area. What is it’s function?
Speech recognition/comprehension
Identify the temporal pole
Identify the middle temporal sulcus/gyrus
Identify the inferior temporal sulcus/gyrus
Where is the insular lobe? What is it’s function?
Primary GUSTATORY cortex
Identify the frontal pole (and occipital pole).
Identify the central sulcus
Identify the olfactory bulb
Identify the olfactory tract
Identify the olfactory stria
Identify the anterior perforated space (substance).
Identify the olfactory fissure.
Identify the gyrus rectus.
Identify the orbital gyrus.
Identify the primary olfactory cortex.
Identify the optic nerve, chiasm, tract.
Identify the pituitary (infundibulum) and its stalk.
Identify the median eminence
Identify the tuber cinereum.
Identify the mammillary bodies
Identify the uncus
Identify the parahippocampal gyrus
Identify the collateral sulcus
Identify the rhinal fissure
Identify the corpus callosum.
Identify the rostrum of the corpus callosum.
Identify the genu of the corpus callosum
Identify the body of the corpus callosum
Identify the splenium of the corpus callosum
Identify the callosal sulcus
Identify the cingulate gyrus.
Identify the cingulate sulcus
Identify the paracentral lobule.
Identify the parieto-occipital sulcus.
Identify the calcarine fissure.
Identify where the primary visual cortex is.
Identify the limbic lobe.
Identify the isthmus (retrosplenial cortex)
Identify the subcallosal gyri of the limbic lobe
Identify the thalamus.
Identify the epithalamus
Identify the subthalamus.
Identify the hypothalamus.
Identify the midbrain
Identify the Pons/cerebellum.
Identify the medulla.
Identify the cerebral peduncle.
Identify the pyramid
Identify the olfactory nerve.
Cranial Nerve I
Identify the optic nerve.
Cranial Nerve II
Identify the oculomotor nerve.
Cranial Nerve III
Identify the trochlear nerve.
Cranial Nerve IV
Identify the Trigeminal Nerve
Cranial Nerve V
Identify the Abducens Nerve
Identify the Facial Nerve.
Cranial Nerve VII
Identify the vestibulo-cochlear nerve.
Cranial Nerve VIII
Identify the glossopharyngeal nerve
Cranial Nerve IX
Identify the Vagus Nerve.
Cranial Nerve X
Identify the Spinal Accessory Nerve.
Cranial Nerve XI
Identify the Hypoglossal nerve.
Cranial Nerve XII
Identify the superior cerebellar peduncle
Identify the middle cerebellar peduncle
Identify the inferior cerebellar peduncle
Identify the pyramidal decussation. Why is it important?
It marks the transition from the brainstem to the spinal cord
Identify the posteromedian fissure
1 in the diagram
Identify the posterolateral fissure.
2 in the diagram
Identify the sensory fibers.
3 in the diagram
Identify the DRGs.
8 in the diagram
Identify the sensory tracts.
5 in the diagram
Identify the anterolateral fissure.
1 in the diagram
Identify the motor fibers.
2 in the figure
Identify the DRGs
3 in the figure
Identify the sensory fibers
4 in the figure
What is a ventricle?
A continuous fluid-filled sac (of CSF)
Identify the lateral ventricle
Identify the anterior horn of the left ventricle
2
Identify the body of the lateral ventricle
1
Identify the inferior (temporal) horn of the lateral ventricle
8
Identify the posterior (occiptal) horn of the lateral ventricles
11
Identify the atrium of the lateral ventricle
Identifyt he interventricular foramen of Monro
4
Identify the third ventricle
5
Identify the optic recess
6
Identify the infundibular recess
7
Identify the habenular recess
9
Identify the pineal recess
10
Identify the interthalamic adhesion
3
Identify the cerebral aqueduct of Sylvius (the aqueduct)
12
Identify the fourth ventricle
14
Identify the foramen of Magendie
13 (Midline Magendie)
Identify the foramina of Luschka
15 (Lateral Luschka)
Identify the central canal
16
Identify the obex
Identify the lateral ventricle
Identify the interventricular foramina of Monro
Identify the third ventricle
Identify the optic recess
Identify the infundibular recess
Identify the habendular recess
Identify the pineal recess
Identify the cerebral aqueduct of Sylvius
Identify the fourth ventricle
Identify the central canal
Identify the lateral ventricle
Identify the Third Ventricle
Identify the foramen of Monro
Identify the aqueduct
Identify the fouth ventricle