Neurotransmission Flashcards
Synapse
Specialised junction where one part of a neuron contacts +communicates with another neuron or cell type
Synaptic Bouton
Axon terminal
End of an axon
Three components of a synapse
Presynaptic membrane
Synaptic cleft
Postsynaptic membrane
Synaptic vesicles
small spherical structure filled with neurotransmitter molecules
Types of Synapses
Electrical and Chemical
Electrical synapses
- Allow direct transfer of ionic current from one nerve cell to another
- Pre and postsynaptic cell membranes are in close apposition to each other
Gap junctions
- Interconnection of many cell types (glial cells) –> function as electrical synapses
- Allows neurons to share info about metabolic state
- Ions can flow through
- formed from connexons
- most allow ionic current to pass in both directions
Anatomy of Electrical Synapse
Gap junction, extracellular space (bridged by connexon)
Chemical Synapses
- Mostly unidirectional
- slower than electrical synapses
- Presynaptic boutons : vesicles that store neurotransmitters
- Postsynaptic density : Protein accumulated in and under membrane
Chemical Synapses in CNS
- Axodendritic Synapses
- Axosomatic Synapses
- Axoaxonix Synapses
- Dendrodentritic Synapses
Neurotransmitters
Excitatory or Inhibitory
Three classes of small molecule neurotransmitters
Amino Acids, acetylcholine and peptides
Neuropeptides
Large molecule neurotransmitters
Amino Acids
Glutamate and Gamma aminobutric acid (GABA)
Monoamines
Catecholamines (Dopamin, Adrenaline, Norepinephrine) and Indolamines (Serotonin)
