Transmission within neurons

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What is the soma?
Contains nucleus
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What are dendrites?
Receive messages
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What are the axons?
Carries info (action potentials) from soma to terminal buttons
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What is the first neuron?
Multipolar, one axon, many dedrites
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What is the bipolar neuron?
One axon, one dendritic tress usually sensory
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What is a unipolar neuron?
One axon divided into two branches. One receives sensory info one sends info to CNS
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What are the between structure connections?
Afferent -brings info to a structure, efferent -carries info from a structure,
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What is a within structure connection?
interneurons entire cell in one structure
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What are the supporting cells?
Glia, including astrocytes, oligodendrocytes, microglia
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What do oligodendrocytes produce?
The myelin sheath that insulates acons
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What is the node of ranvier?
Naked axon
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What do cells provide?
waste services, supply of nutrients and chemicals
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What is the transmission within a neuron?
A electrical process, all cells have an electrical charge, they are more negative on the inside than the outside, neurons transmit info by producing a temporary change in the target neuron's polarity
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What is the membrane potential balanced by?
diffusion (movement of molecules from regions of high concentration to regions of low concentration) and electrostatic pressure (attraction/repulsion of particles depending on charge, e.g., +ve and –ve attracted)
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What are the two types of ions?
Cations +Vely charged, Anions -vely charged
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What does the intercellular fluid?
Contains potassium ions
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What is extracellular fluid?
contains sodium and chloride ions
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What is K+ in resting potential?
Diffusion: wants to move out, but electrostatic: attracted to -Ve inside
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What happens to CL- during resting potential?
Diffusion:wants to move in, electrostatic: repelled from -ve inside
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What is Na+ during the resting potential?
Diffusion: wants to move in Electrostatic: attracted to -ve inside
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How is Na+ kept under control?
by sodium potassium pumps
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How is the neuron kept at equillibrium?
Na+ pumped out, k+ pumped in
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What is the resting potential?
-70Mv
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What is a polarized neuron?
Inside: negative, outside: positive
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What do neurons do?
Quick rapid changes in this polarisation, called an action potential, this is how neurons send electrical signals
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What is depolarisation?
Decrease from normal resting potential (brings membrane closer to 0)
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What is hyperpolarisation?
Increase relative to resting potential (more negative)
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What happens after the threshold of excitation?
Na+ channels open, Na+ begins to enter cell, K+ channels open, K+ begins to leave cell, Na+ channels become refractory no more Na+ enters cell
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What happens after depolarisation?
K+ continues to leave cell, causes membrane potential to return to resting level
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What happens after repolarisation?
K+ channels close and Na+ resets,
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What happens during hyperpolarisation?
Extra K+ outside diffuses away
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What is saltory conduction?
Action potential regenerated along the axon at nodes of ranvier
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What are the benefits?
Fast conduction, more energy efficient
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What are synaptic transmission?
Transmission of message through synapse, a chemical process using neurotransmitters, produce postynaptic potentials
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what is a synapse?
The junction between two neurons
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What is the first synaptic transmission?
Transmitter is synthesised and then stored into vesicles
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What invades the presynaptic membrane?
An action potential invades the presynaptic terminal
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What happens next?
Depolarisation of presynaptic terminal causes opening of voltage gated Ca2+ channels
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What happens after the depolarisation?
Influx of Ca2+ through channels, CA2+ causes vesicles to fuse with presynaptic membrane
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How is the transmitter released?
INto synaptic cleft via exocytosis
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What happens next?
Transmitter binds to receptor molecules in post synaptic membrane, opening or closing of post synaptic channels
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What does post synatpic current cause?
Excitatory and inhibitory postsynaptic potential that changes thee excitability of the post synaptic cell
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How is the neurotransmitter removed?
glial uptake or enzymatic degradation
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What happens last?
Retrieval of vescular membrane from plasma membrane
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What is binding?
Neurotransmitter binds to ion channels on post synaptic membrane, Postsynaptic potential depends on which ion channel (lock) is opened
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What is a ionotropic receptor?
Contains a binding site, opens when molecule attaches to binding site
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What is a metabotropic receptor?
Contains a binding site. Initiates a chain reaction that eventually opens ion channels, PSPs slower than those produced by ionotropic receptors
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What is first way of terminating a neurotransmitter?
Enzymatic deactivation/degradation where the transmitter broken down by an enzyme
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For example?
Acetylcholinesterase breaks down Ach into choline and acetic acid
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What is another way of terminating a neurotransmission?
Transmitter is taken back by the presynaptic terminal
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What is the two neural integration?
Excitatory;increases likelihood of neuron firing and inhibitory: decreases likelihood
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What is integration?
Summation of PSPs in control of neuron firing
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What happens due to the inhibition of inhibitory neurons?
More likely of behaviour
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What happens due to the excitation of inhibititory neurons?
Less likelihood of behaviour
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What is the most abundant excitory neurotransmitter?
Glutamate, it can bind to receptors
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What are they responsible for?
Learning and memory
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What is the most abundant inhibitory neurotransmitter?
GABA
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What does it do?
REduces chance of neuronal firing
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Where is Acetylcholine found?
In CNS and PNS. Specifically at neuromuscular junctions
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What is Curare?
A poison that prevents muscle contraction and blocks the action of ACH (an antagonist)
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Where is a monoanine produced?
by neurons in the brain, G protein coupled. Excitatory or inhibitory depending on receptor subtype
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What is dopamine responsible for?
Motor control, reward, addiction
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What is serotonin responsible for?
Regulation of mood, eating, sleep, arousal and pain
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Other cards in this set

Card 2

Front

What are dendrites?

Back

Receive messages

Card 3

Front

What are the axons?

Back

Preview of the front of card 3

Card 4

Front

What is the first neuron?

Back

Preview of the front of card 4

Card 5

Front

What is the bipolar neuron?

Back

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