PHSI 208 Lecture Notes - Lecture 10: Chemical Synapse, Axon Terminal, Axoplasmic Transport
Document Summary
Vesicles containing neurotransmitter accumulate in the axon terminal ready to be released on demand: there"s also an abundance of mitochondria as you need atp to package the vesicles. Large peptide neurotransmitters are produced and packaged into vesicles at the soma and transported (fast axonal transport) Small neurotransmitters are synthesized and packaged at the axon terminal (empty vesicles transported from soma or recycled vesicles) Enzymes for synthesis brought to terminal via slow axonal transport. *exocytosis in a neuron occurs through the opening of a fusion pore not through incorporation of the vesicle w/ the plasma membrane. Vesicle slightly binds to the membrane, fuses with it and opens a little bit to allow contents to leave. Then the vesicle closes and goes back into the presynaptic terminal. Neural signaling is of short duration due to the rapid removal or inactivation of neurotransmitter in the synaptic cleft: the chemicals are broken down, are taken up into cells, or diffuse away from synapse.
