Neurons [Synaptic] Flashcards
Description of what happens at a chemical synapse (pre to post)
Depolarisation at the presynaptic terminal causes release of a neurotransmitter which diffused across the synaptic cleft and binds to receptors in the postsynaptic membrane. This initiates opening of a channel and a current therefore.
3 key features of chemical synapses
Specificity of neurotransmitters
Complexity
Plasticity (learning developing)
2 types of chemical synapses
Excitory: evoke depolarisations of the postsynaptic membrane called EPSPs.
Inhibitory: evoke hyperpolarisations of the postsynaptic membrane called IPSPs.
Excitatory synapses neurotransmitter and channels
Glutamic acid (glutamate) and ACh. Opens channels for Na+ K+ and Ca2+
Inhibitory synapses neurotransmitters and channels
GABA or glycine. Opening of K+ channels.
Factors determining synaptic action
Type of neurotransmitter
Type of complex
Amount of neurotransmitter
Synaptic plasticity - LTP or LTD
3 types of glutamate receptors + whats glutamate for? What ions do the receptors allow through?
Glutamate is a neurotransmitter for excitatory synapses. AMPA(K/Na), NMDA (allows everything), Kaitane (K/Na)
What is EPP?
End plate potentials. Ion channels open which are non-selective cationic. Trigger AP.
What do temporal and spatial summation enhance?
EPSPs amplitude
Spatial summation
2 presynaptic neurons, 1 postsynaptic neuron.
Temporal summation
1 presynaptic, 1 post.
More calcium released and not enough time to remove it so increase in neurotransmitter release with shorter interval.
Direct gating - description + speed
Transmitter binds to receptor/channel complex, hyper/depolarising membrane. Fast and short-lasting.
Indirect gating - description + speed
Transmitter binds to receptors such as metabotropic (G protein). Activates cAMP and kinases causes channels to open and changes membrane potential. Slower and longer-lasting
Small molecule/classical neurotransmitters - speed, direct/indirect, types
Fast, act directly on receptors.
Amino acids, ACh, amines.
Neuropeptides
Large, indirect (metabotropic), slow.