Different types of synapses
- Created by: 08rmorris
- Created on: 04-04-15 11:25
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- Different types of synapse
- 1. Excitatory ion-channel synapses
- These synapses have neuroreceptors that are sodium (Na+) channels
- When the channels open, positive ions diffuse in, causing a local depolarisation called an excitatory postsynaptic potential (EPSP)
- Making an action potential more likely
- acetylcholine glutamate asparate
- Making an action potential more likely
- When the channels open, positive ions diffuse in, causing a local depolarisation called an excitatory postsynaptic potential (EPSP)
- These synapses have neuroreceptors that are sodium (Na+) channels
- 2. Inhibatory ion-channel synapses
- These synapses have neuroreceptors that are chloride (Cl-) channels.
- When the channels open, negative ions diffuse in causing a local hyper polarisation called an inhibitory postsynaptic potential (IPSP)
- making an action potential less likely
- An impulse in one neurone can inhibit an impulse in the next
- Glycine GABA
- An impulse in one neurone can inhibit an impulse in the next
- making an action potential less likely
- When the channels open, negative ions diffuse in causing a local hyper polarisation called an inhibitory postsynaptic potential (IPSP)
- These synapses have neuroreceptors that are chloride (Cl-) channels.
- 3. Non-channel synapses
- These have neuroreceptors that are not channels at all
- but instead are membrane-bound enzymes
- When activated by the NT, they catalyse the production of a "messenger chemical" inside the cell, which in turn can affect many aspects of the cell's metabolism
- In particular they can alter the number and sensitivity of the ion channel receptors in the same cell
- These synapses are involved in slow and along-lasting responses like learning and memory
- adrenaline noradrenaline dopamine serotonin endorphin angiotensin acetylcholine
- These synapses are involved in slow and along-lasting responses like learning and memory
- In particular they can alter the number and sensitivity of the ion channel receptors in the same cell
- When activated by the NT, they catalyse the production of a "messenger chemical" inside the cell, which in turn can affect many aspects of the cell's metabolism
- but instead are membrane-bound enzymes
- These have neuroreceptors that are not channels at all
- 4. Neuromuscular junctions
- these are synapses formed between effector neurones and muscle cells
- they always use the NT acetylcholine and are aways excitatory
- Effector neurones also form specialised synapses with secretory cells
- they always use the NT acetylcholine and are aways excitatory
- these are synapses formed between effector neurones and muscle cells
- 5. Electrical synapses
- in these synapses the membranes of the 2 cells actually touch
- they share proteins
- This allows the action potential to pass directly from one membrane to the next without using a NT
- They are very fast, but are quite rare, found only in the heart and the eye
- This allows the action potential to pass directly from one membrane to the next without using a NT
- they share proteins
- in these synapses the membranes of the 2 cells actually touch
- 1. Excitatory ion-channel synapses
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