Lecture 1, 2 - Neurons Ch 8 F08

8/8/2019 Lecture 1, 2 - Neurons Ch 8 F08

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Organization of the nervous system

8-1


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Model neuron

8-2


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Axonal transport

8-4


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There are 3 functional classes of neurons

8-3


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8-5


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The neuropil of the CNS

8-6


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8-6


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Knowledge of the electrical properties of neurons is essential to

understanding how the the nervous system works.

5-37


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5-33

Apparatus for intracellular recording of membrane potential


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The fluid mosaic model of membranes

3-4r


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Leak conductance channels

Ligand activated channels

Voltage-gated channels

Mechanically-gated


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The genesis of an equilibrium potential

5-34


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5-34


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5-34


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5-35


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Eion = RTZF ln [ion]1

[ion]2Nernst eqn.

Eion = log [ion]1

[ion]2

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Fig 5-30


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Goldman, Hodgkin, Katz eqn.

Em =61 log Pk [K]oPk [K]i

PNa [Na]oPNa [Na]i

++

PCl [Cl]iPCl [Cl]o

++

The resting membrane potential of a cell that is

permeable to multiple ionic species can be calculatedusing the Goldman, Hodgkin, Katz equation


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Passive spread of graded potentials

8-7r


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Graded potentials can lead to the initiation of an action potential

8-8


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8-8


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The generation of an Action Potential

8-9


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The operation of a voltage-gated Na channel

8-10


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Action potentials are regenerative events involving positive

feedback in which membrane depolarization actives voltage-

gated Na channels that depolarize the membrane

8-11


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8-12

Stimulus strength is encoded by receptor potential amplitude, action potential


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Stimulus strength is encoded by receptor potential amplitude, action potential

frequency and the quantity of transmitter release

8-13


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Mechanism of action potential propagation

8-15


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8-15


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8-15


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8-16


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8-17

Saltatory conduction along a myelinated nerve


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Saltatory conduction along a myelinated nerve

8-18


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Electrolyte imbalance can disrupt electrical signaling

8-19


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Ionic currents are

measured using voltageclamp technology


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Patch clamp measurements

of single voltage dependent

sodium channels

ensemble average curent

single current traces


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Secondary structure of voltage-gated sodium channel


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Voltage sensor

activation gate

Families of voltage-gated channels


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Families of voltage-gated channels


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Mechanisms of synaptic transmission

8-20


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8-21

Synthesis and recycling of Ach at a synapse


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8-22

Synthesis and recycling of Ach at a synapse


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Mechanisms for terminating the action of neurotransmitters

8-24


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8-25


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8-25


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Neurons integrate the activity of

many synaptic inputs

8-26


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Temporal summation


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Temporal summation

8-28


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8-28


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8-29

Long term potentiation involves the


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g p

coordinated activities of two

classes of glutamate receptors

8-30


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Peripheral nerves have a strong regenerative potential following injury

** CNS neurons also regenerate

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Lecture 1, 2 - Neurons Ch 8 F08