PSYC1002 Lecture Notes - Lecture 8: Lipid Bilayer, Myelin, Diazepam
19 May 2018
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Neuron anatomy
Screen clipping taken: 4/11/2017 12:32 PM
Screen clipping taken: 4/11/2017 12:32 PM
Signals transmitted from dendrites to terminals
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Send binary (ON/OFF) signals, neurons are digital so can only convey one bit of info at a time
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Prevents depolarisation
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Depolarisation can only occur at GAPS between myelin sheath
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Myelin speeds up propagation of action potential jumping form gap to gap
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Neurons with myelin = faster
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Myelin
Action potential
Neurons covered in lipid membrane
L3 - anatomy and physiology of neurons
Saturday, 4 November 2017
12:32 PM
Neuroscience Page 1
Semipermeable
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Neuron can control conc of positive and
negative ions inside
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Neurons covered in lipid membrane
Screen clipping taken: 4/11/2017 12:42 PM
Inside neuron negative compared to outside
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Polarised
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Neuron is OFF
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Resting state
Screen clipping taken: 4/11/2017 12:42 PM
All or nothing
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Neuron opens ion channels so it is
depolarised
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Neuron is switched ON
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Localised to small segment of membrane
and then spreads along
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Hyperpolarisation after AP prevents it from
moving back on itself
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Action potential
Screen clipping taken: 4/11/2017 12:43 PM
Form small junctions called synapses, which neurons communicate across
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Screen clipping taken: 4/11/2017 12:48 PM
Synaptic cleft is 10-20nm wide -> transmission VERY fast
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Chemical synapses - vast majority of neurons communicate via chemical transmission across
synapse
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Interaction between neurons
Neuroscience Page 2
Document Summary
Send binary (on/off) signals, neurons are digital so can only convey one bit of info at a time. Depolarisation can only occur at gaps between myelin sheath. Myelin speeds up propagation of action potential jumping form gap to gap. Neuron can control conc of positive and negative ions inside. Neuron opens ion channels so it is depolarised. Localised to small segment of membrane and then spreads along. Hyperpolarisation after ap prevents it from moving back on itself. Form small junctions called synapses, which neurons communicate across. Chemical synapses - vast majority of neurons communicate via chemical transmission across synapse. Synaptic cleft is 10-20nm wide -> transmission very fast. As action potential arrives at terminal of 1st neuron, neurotransmitter chemicals released into synapse from terminal. Nts diffuse across synapse and bind to receptors on 2nd neuron. Binding of nt to receptor causes changes in 2nd neuron. Nts can be excitatory (promote action potential in 2nd neuron) or inhibitory (block action potential)
