Synaptic Transfer And Neurotransmitters Flashcards
What are synapses?
The physical gaps that separate neurons from other neurons and receptor or effector cells
How do neurons transmit information?
Convert electrical signal into chemical signal
What is the first step of the chemical transfer across synapses?
A neurotransmitter is synthesised and stored in vesicles of the presynaptic neuron.
What happens after a neurotransmitter is made and stored in vesicles of the presynaptic neuron?
Action potential reaches the presynaptic terminal.
What happens after an action potential reaches the presynaptic terminal?
The presynaptic terminal depolarizes which results in the voltage gated calcium channels to open
What happens when the voltage gated calcium channels opens?
There is an influx of calcium through channels
What happens when calcium flows through the voltage gated calcium channels?
The vesicles containing the neurotransmitter fuse with a presynaptic membrane.
What happens when the vesicles fuse with a presynaptic membrane?
The neurotransmitter is released from presynaptic neuron into the synaptic cleft via exocytosis.
What happens when the neurotransmitter is released into the synaptic cleft?
The neurotransmitter binds to receptor molecules, called ligand gated ion channels, on the postsynaptic membrane
What is a ligand?
A chemical messenger
What happens when the neurotransmitter binds to the ligand gated ion channel?
Opening or closing of postsynaptic ion channels (for example if Na + channels are opened, Na + ions will enter the postsynaptic neuron and depolarize the neuron, possibly initiating an action potential).
What happens when the ligand gated ion channels open or close?
The membrane potential of postsynaptic neuron changes (for example, depolarized if sodium channels are opened), which affects whether the postsynaptic cell may have an action potential.
What happens when the membrane potential of the ligand gated ion channels changes?
The vesicular membrane is retrieved from the plasma membrane of the presynaptic neuron
What is acetylcholine?
created in the axon terminal by combining choline with an acetyl group (derived from mitochondrial Acetyl CoA)
What two classes of specific receptors does acetylcholine bind to?
Nicotinic and muscarinic