Synapses 2 5.3.6
Synapses and nervous communication
Nerve junctions can involve several neurones
Excitatory post-synaptic potential
Only a few vesicles fuse w/ pre-synaptic membrane
A small number of acetylcholine molecules diffuse across synaptic cleft
Small depolarisation and action potential isn’t produced
Combination of several EPSPs to reach threshold value to cause an action potential – summation
Temporal summation – several action potentials in same pre-synaptic neurone
Spatial summation – action potentials arriving from several different pre-synaptic neurones
Inhibitory post-synaptic potentials
Reduces effect of summation and prevents an action potentials in post-synaptic neurone
Control of communication
Spatial summation creates specific responses e.g several different stimuli warn us of danger
Several ESPSs can be prevented Form creating an A.P by one IPSP
Synapses ensure A.P travel in one direction
Synapses and nervous communication
Nerve junctions can involve several neurones
Excitatory post-synaptic potential
Only a few vesicles fuse w/ pre-synaptic membrane
A small number of acetylcholine molecules diffuse across synaptic cleft
Small depolarisation and action potential isn’t produced
Combination of several EPSPs to reach threshold value to cause an action potential – summation
Temporal summation – several action potentials in same pre-synaptic neurone
Spatial summation – action potentials arriving from several different pre-synaptic neurones
Inhibitory post-synaptic potentials
Reduces effect of summation and prevents an action potentials in post-synaptic neurone
Control of communication
Spatial summation creates specific responses e.g several different stimuli warn us of danger
Several ESPSs can be prevented Form creating an A.P by one IPSP
Synapses ensure A.P travel in one direction
