Neuron to neuron and Neuron to Muscle can only occur when AP reached axon terminal.
They do not touch cell - space between cells are SYNAPSES
AP = PRESYNPATIC --> SYNAPTIC CLEFT --> POSTSYNAPTIC
EXCITATORY ---> DEPOLARISE --> ENCOURAGE AP
INHIBITORY --> HYPERPOLARISE --> INHIBIT AP
Synaptic events following the arrival of the actio
AP reaches presynaptic presyn depolarise cause calcium channels to open release neurotransmitter by exocytosis - very rapid - binds to postsynaptic receptors.
neurotransmitter removed after activation (enzymatic degradation)
Synapses with only one nerve are very rare
One neuron can recieve thousands of synapses, APs may arrive from more than one nerve and may cause increased excitation (EPSP) or increased inhibition (IPSP).
convert environmental change to nerve impulses - allow us to sense change - can be both concious and AUTONOMIC
SERIES OF EVENTS - 1.stimulation of sensory nerve
2. receptor activation
3. change in membrane potential
4. AP propagated to CNS
5. Integration to CNS
Sensitivity is determined by density of sensory receptor