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62 Cards in this Set
- Front
- Back
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Astrocytes
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At the BBB; provides structural and chemical supports and nutrients for neurons
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Microglia
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Scavengers; clean up messes ( neurons that die can be toxic, they clean it all up) - smallest
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Oligodendroglia
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Myelinate axons ONLY in the CNS
-inhibit regeneration of axons |
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Schwann Cells
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Myelinate axons ONLY in the PNS
-regrow after injury (e.g., deep cut and you lose sensation for awhile but it comes back) |
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Bipolar Cells
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Sensory neurons (e.g., retina)
- can only have one dendrite and one axon) |
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Pyradmidal cells
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predominately in the Cerebral cortex, hippocampus
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What are the four PHENOTYPES neurons may take?
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Bipolar cells
Pyramidal cells Purkinje cells Granule cells |
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Principle components of a neuron
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Dendrites: receive information; spines: little outgrowths that form synapses
Soma: the cell body (receives information)- Contains - endoplasmic reticulum and nucleus - synapses also form here Axons - transmit information; only one axon per neuron, though it branches (bifurcates) - AP starts here and leads to the terminal |
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Axon hillock
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the initial segment leaving the cell body (integration zone) -where the voltage gated NA+ channels are
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Myelin Sheath
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Fatty covering of the axon; increases speed of conduction (15 times faster than unmyleninated)
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Node of Ranvier
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Gaps in between the mylein where potentials are regenerated
-keeps the strength of the potential the same all the way through |
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Axon terminal/bouton/button
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forms the synapse with another neuron; releases NT
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Endoplasmic Reticulum
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translates protein
-takes mRNA and makes protein out of them |
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Nucleus
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contains DNA and transcribes mRNA
- every cell in your body, with the exception of red blood cells, have ur DNA. |
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DNA
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a reciple for how to make a specific protein/enzyme
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Genometric acitivty
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make more/less of a particular protein (e.g., inhibitory or excitatory)
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What is Electrical transmission
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how neurons conduct electricity
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transmission (ion channels)
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- Ions are kept either inside or outside the cell membrane, depending on type
-inside of membrane is -70mV -specific, only one type of ion gets through -ion channel opens ip, ions rush through (this is called a potential) - and alters the resting potential (-70mV polerization) |
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EPSP (Excitatory Post- Synaptic potential)
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-increases resting potential (makes it positive. closer to zero)
-sends a message to fire the neuron -depolarizes the neuron |
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IPSO (inhibitory Post- Synaptic potential)
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- Decreases the resting potential (makes it more negative - further from zero)
- tries to prevent cells from firing - hyperpolarizes the neuron - prevents over excitement of a neuron - which will cause it to explode; this is harmful to the rest of the body bcuz it is toxic |
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The Action Potential
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technical term for firing of a neuron
message is genereated from the axon hillock (Which determines if there is enough stimulation to fire or not) - hillocks has a tonne of NA+ channels - with a large enough change at the hollock (resting potential) these channels open and NA+ rushes in (past the threshold) |
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Absolute Refractory Period
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For a brief millisecond the cell CAN NOT fire again, no matter what.
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Relative Refractory Period
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the cell can fire, bit requires higher than normal levels of stimulation (follows after the ARP)
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Sodium potassium Pump
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regulates sodium and potassium after an action potential to maintain homeostasis.
-bcuz after AP the sodium is inside the cell and potassium is inside (Na+ K pump fixes this) -Uses the most energy than any other mechanism in the brain -active transport |
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Concentration gradient
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ions will move from an area of high concentration to an area of low - in order to regulate
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Electrostatic pressure
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ions move from an area of similar charge to an area of opposite charge
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Saltatory conduction
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"skipping; jumping"
NA+ travel down the axon Nodes of Ranvier contain more voltage fated NA+ channels; which open up when AP hits them this ensures the strenght of the AP is maintained |
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The Cains & toxins
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Both block NA+ channels
Bind to NA+ channels and prevent AP: no msg =no pain The Cains: cocaine, lidocaine, novacaine However; toxin dp the same thing as the Cain's but they do it so well they kill u :Tetrodoxin (Pufferfish), saxitoxin (shellfish), conotocin (cone shells) |
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Multiple Sclerosis
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is a degeneration of this myelin (oligodendrocytes)
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Epilepsy
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all the neurons in a given area start to have AP's at exactly the same time
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Divisions of the Nervous system
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CNS: Brain and spinal cord
PNS: everything else PNS divided into 2: Somatic Nervous system: sensory and motor control Autonomic Nervous System: control of organs that we cannot stop/start at our command (e.g., heart/digestion) the ANS is divided into 2: Parasympathetic: average everyday activities (breahting etc..) -- acetylcholine Sympathetic: When shit goes down - fight or flight (Norepinephrine) |
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Basal ganglia
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-Forebrain
-"princess leia hair wraps on each side of the brain" includes: caudate nucleus, thalamus, globus pallidus and putament -involved in movement (uses dopamine from midbrain), learning thalamus: the gateway for sensory info. (everything goes thru here except olfactory) -Lots of dopamine in these areas |
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Huntingtons disease
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single gene mutation that preferentially affects cells in the basal ganglia
cant stop moving - uncontroble movement |
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Parkinsons disease
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a substantial loss of DA (dopamine) containin neurons in the substantial nigra (opp. of huntings - very difficult to move)
L Dopa helps but if to much is given patients act as though they have huntingtons |
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The limbic System
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frontal lobe
thalamus hippocampus thalamus amygdala hypothalamus |
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Neurotransmitter
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neurons send msgs to one another primarily through chemical mechanisms
this involves the release of a NT from an axon that has formed a synapse with another cell Neurotransmitters BIND on the outside of the receptor; they signal using a lock and key mechanism receptors can be ionotropic or metabotropic |
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Exocytosis
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Na+ opens Ca2+ channels and releases NT
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What are the three types of chemical signaling
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Axodendric
Axosomatic Axoaxonic |
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Agonist
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a molecule that activates a receptor site --mimics
-excitatory; increases arousal e.g., endogenous NT or neurohormone |
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Antagonist
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a molecule that inhibits or blocks the activity of a "ligand", the endogenous NT.
-Achieved by BINDING to receptor and preventing the subsequent binding of active ligands -- dosnt do anything but block another NT from doing something |
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NT breakdown
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two basic mechanisms of cellular recycling
1.) Reuptake 2.)Enzyme degradation |
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Ionotropic receptors
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5 subunits that come together in the cell membrane to form the complete receptor.
produces EPSP or IPSP |
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Metabotropic receptors
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NT bound to G protein receptor
Single protein can alter function of ion channels can also affect the synthesis of other chemicals called 2nd msgs |
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2nd MSG
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can alter ion-channel functioning
Can lead to genomic effects Activate Kinases: -which causes phosphorylation - alters protein functions --- increase receptor sensitivity --- turn on enzymes --- activate proteins that bind to DNA |
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Lesions
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chemical lesion - freeze area but passing fibers are still intact
electrical lesions; pimp electricity to the region, fry it and it never comes back - passing fibers cant go thru |
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Microinjections
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direct injections to a specific brain region
ICV ; type of injections only used on animals; injected into the ventricles. |
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Microdialysis
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sampling extracellular fluid to look at levels of particular chemicals (see its effects of chemical compotions)
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EEG
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record cell activity in functioning animals
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Ligand Binding/Autoradiography
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Use radiolabelled ligand to examine receptor numbers
tissue homogeneate: grind up brain regions Autoradiography: same thing but w/ tissue slices and exposure to film |
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Radioimmunaossy
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use a radiolabelled antibody to bind to an antigen in fluid(blood/saliva) to see how much of a hormone is in the blood
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Immunocytochemistry (ICC)
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raise an antibody to a specific region and apply to tissue slices
Tells you how much of the antigen is where. |
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PET
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locates the accumulation of a radioactive signal given to patient - finds activated areas during specific tasks
-Tells you function not structure |
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CAT
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Brain X-ray
2D -Tells you structure not function |
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MRI
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3D brain pictures
Expensive High resolution Tells you structure, not function |
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fMRI
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produces nice pictures
shows you areas of activation at the time of the scan via oxygenation of the blood |
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Animal behaviour
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Used to asses different behaviour - particularly in response to drugs
all new meds need to be tested on animals used to asses motor activity, analgesia, anxiety, depression, cognition, fear and reward |
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Morris Water Maze
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Spatial test
big pool filled with a milk liquid w/ a hidden platform |
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Radial Arm Maze
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looks at working memory; also spatial test
-you can also put this in water |
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Elevated Plus Maze
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Anxiety
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Forced Swim test
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depression through learned helplessness then we give them antidepressants and see if the rat tries to swim - if so they are working-ish.
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Operant tests
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-2 types
--- Conflict/Geller- Seifter tests to measure anxiety --- Drug schedule: lever pressing |
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Place Preference
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examines the rewarding properties of drugs
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