Lecture 5 Flashcards
flow of information at a synapse
-information flows in one direction (neuron –> target cell or organ)
-first neuron (presynaptic neuron)
-target cell (postsynaptic cell)
electrical synapse
-very rapid transmission
-bidirectional transmission
chemical synapse
-slower
-generates postsynaptic potentials (PSPs)
-synaptic integration
potential produced by electrical synapses
-postsynaptic potential has the same shape as an action potential
-the amplitude depends on the coupling efficiency, a product of the number of gap junctions linking the two cells
axo-dendritic chemical synapse
axon to dendrite
axo-somatic chemical synapse
axon to soma
axo-axonic chemical synapse
axon to another axon
dendro-dendritic synapse chemical synapse
one dendrite to another
transmission at chemical synapse
- neurotransmitter synthesis
- loading of neurotransmitter into vesicles
- fusion of vesicle to membrane at presynaptic nerve terminal
- release of neurotransmitters into synaptic cleft
- binding of neurotransmitter to post-synaptic receptors
- post-synaptic response (1. electrical (PSPs) 2. biochemical (intracellular pathways))
- removal of neurotransmitters from synaptic cleft
peptides
-synthesized in the endoplasmic reticulum
-activated and packed in Golgi apparatus before being transported to nerve terminals
amino acids and amines
-synthesized by enzymes at nerve terminals
-transported to empty vesicles at nerve terminals
exocytosis
process by which vesicles release their content
release of neurotransmitters
- vesicles are loaded with neurotransmitters (NT)
- the arrival of an action potential activates voltage-dependent Ca2+ channels
- Ca2+ stimulates movement of vesicles to the membrane, fusion, and release of NTs into synaptic cleft
- recapture of vesicle for reuse
