L05: Synapses And The Role Of Neurotransmitters Flashcards
How do 2 neurones communication
Via synapses
What are the types of synapses
Electrical
Chemical
What is an electrical synapse also known as
Gap junctions
What is direction of action potential in electrical synapses
Bidirectional
What are the physical features of an electrical synapse
Physical connection by connexons
What is 1 connexon made of
6 connexins
What is the direction of transfer in chemical synapses
One direction
What are the physical features in a chemical synapse
Vesicles are released to the post synaptic neurone
Describe the processes that occur at a chemical synapse
1) AP arrives at the pre-synaptic terminal
2) depolarisation causes voltage gated calcium channels to open
3) calcium ions trigger exocytosis of neurotransmitters
4) neurotransmitters move by simple diffusion
5) neurotransmitters bids to receptors on the post-synaptic membrane
What happens at the post-synaptic membrane to terminate the signal
Neurotransmitter is taken up back into the pre-synaptic terminal and metabolised buy mitochondria
OR
Enzymes at the post-synaptic membrane breakdown the neurotransmitter
What are the major amino acid neurotransmitters
Glutamate
GABA
What type of neurotransmitter is GABA
Inhibitory
What are the monoamines neurotransmitters
Noradrenaline
Dopamine
Serotonin
What are the other neurotransmitters
Acetylcholine
Opioids
What are the 2 main mechanisms at the receptors of the post-synapse
Ionotrophic mechanism
Metabotrophic mechanism
What is the ionotrophic mechanism
1) Neurotransmitters binds to give a conformational change to the receptor
2) Channels open
3) Sodium influx occurs to give depolarisation
Which channel opens when GABA binds to its receptor
Chloride channel
What activity does GABA cause inside the cell
Hyper polarisation
What is the metabotrophic mechanism
1) neurotransmitters binds to receptor and conformational change occurs
2) conformational change triggers G-proteins
3) activated G-proteins open ion channels and stimulate 2nd messengers
What spatial summation
When more than one neurone integrates information to one post synaptic membrane
Excitation is added together to reach threshold value and generate AP
What is temporary summation
When one synapse repeatedly fires to one post-synaptic membrane
The inputs build up to reach threshold value and generate AP
