Learning Objectives

Know the parts of a neuron and how their respective region identification
- Dendrites : Receptive Region
- Axon : Conducting Region
- Axon Termini : Secretory Region
Know that Na/K pumps (and other pumps) are everywhere and:
- establish ion concentration gradients
- establish the resting membrane potential
- given a pump, be able to predict relative ion concentrations
- given a ion concentration gradient, be able to predict how it was established (pump)
Know the protein (i.e. channel) composition of each region
- Dendrites: Variable: typically chemically-gated ion-channel (chemical = neurotransmitter)
- Axon: voltage-gated Na⁺-channels & voltage-gated K⁺-channels
- Axon Termini: voltage-gated Ca²⁺-channels & Storage Vesicles
Understand the graphs of membrane potential
Understand how and EPSP or IPSP is generated
- given a chemically-gated ion-channel, be able to predict if an EPSP or IPSP is generated
- understand that the return to resting is caused by the pumps
Understand how action potentials are generated and what the different phases are
- EPSPs trigger (while IPSPs inhibit) opening of the voltage-gated Na⁺-channels
- Na⁺ Influx = depolarization phase
- depolarization phase triggers opening of voltage-gated K⁺-channels = repolarization phase
- hyperpolarization phase = period below resting where the channels have reset, and the Na/K-pump is still restoring ion concentrations back to resting state
Understand the spread of Action Potentials down the axon
- the depolarization of the AP triggers the next AP (voltage-gated Na⁺-channels) on the axon
Understand how secretion occurs
- axon opens voltage-gated Ca²⁺-channels
- Calcium triggers exocytosis = release of neurotransmitters
Understand the neurotransmitter release is terminated (ended)
- enzyme degradation - enzymes in cleft destroy neurotransmitters
- reuptake - pump (or other system) recycles neurotransmitters by transporting them back to the storage vesicles
Know the general signaling pathway
- NT -> EPSP (or IPSP) -> AP -> NT Release

Terms

synapse
Cleft
ligand
receptor
ligand-gated ion-channel
vesicle

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A cool Simulation of an Action potential