synaptic transmission

Question 1

what is synaptic transmission?

Answer 1

the process by which neighbouring neurons communicate with each other by sending chemical messages across the gap (synapse) separating them

neurons communicate with each other within groups (neural networks)
signals within neurons transmitted electrically
signals between neurons transmitted chemically across synapse

electrical impulse reaches presynaptic terminal (end of neuron)- triggers release of neurotransmitter from synaptic vesicles

Question 2

what are neurotransmitters?

Answer 2

chemicals that relay signals across the synapse from one neuron to another

diffuse across synapse to next neuron in chain
crosses synapse- taken up by postsynaptic receptor site on dendrites of next neuron
chemical message converted back to electrical impulse- process of transmission begins again

direction of travel only one way
released by presynaptic neuron and received by postsynaptic neuron

Question 3

types of neurotransmitters

Answer 3

each has its own specific molecular structure that fits perfectly into a postsynaptic receptor site

either have excitatory or inhibitory effect on neighbouring neuron

specialist functions
e.g. acetylocholine- found where motor neurons meet muscles, causes muscles to contract upon release

Question 4

excitation and inhibition

Answer 4

exication- neurotransmitter increases pos charge of postsynaptic neuron
increases likelihood that PSN will pass on electrical impulse
e.g. adrenaline

inhibition- increases neg charge of PSN
decreases likelihood it will pass on electrical impulse
e.g. serotonin

Question 5

summation

Answer 5

process that decided whether PSN fires

excitatory and inhibitory influences summed
e.g. net effect of PSN is inhibitory then the PSN less likely to fire, and vice versa

action potential of PSN only triggered if sum of excitatory and inhibitory signals at any one time reaches the threshold