Synapses and synaptic transmission

A junction between two neurons where information is transmitted from one neuron to the next.

involves chemical communication across a narrow gap between neurons, transforming electrical action potentials into chemical messages

Neurotransmitters are released from presynaptic vesicles, diffuse across the synaptic cleft, and bind to postsynaptic receptors, causing excitatory or inhibitory effects

the neurone that sends the signals across the synapse by releasing NTs into the synaptic cleft

the neurone that receives the signal -it has receptors on its membrane and binds with NTs to continue the impulse

the gap between neurones where diffusion occurs

increases the liklihood of a postsynaptic AP eg glutamate

decreases the likelihood of a postsynaptic AP eg GABA

Synaptic transmission occurs when an action potential reaches the presynaptic terminal, causing neurotransmitters to be released from vesicles into the synaptic cleft. The neurotransmitters diffuse across the gap and bind to specific receptor sites on the postsynaptic neurone in a lock-and-key manner. This increases the likelihood of a new action potential being generated if sufficient excitation occurs. Neurotransmitters are then either broken down by enzymes or reabsorbed via reuptake.

1-the impulse/ NT is released from the presynaptic neurone through the axon terminal

2-once the NT reaches the end of the synapse, the lock and key theory decides which ones diffuse out and which dont

3-as the firing rate from the USN keeps increasing, this leads to a build up of neurones in the synaptic cleft

4-the ion channels are connected the receptors that open meaning that positive charge reaches the neurone and AP is triggered in the DSN

5-the higher the conc of NT, the higher the probability of NT that will fit the receptors so more AP’s triggered

6-AP regulated through either: enzymes that attack and breakdown the NT or by reuptake which is when little pumps pull back the NT and recycle them so the downstream rate falls and prevents continuous stimulation