Features of synapses

Question 1

What do synapses ensure

Answer 1

They ensure that action potentials are only transmitted from the pre-synaptic neurone to the post-synaptic neurone

Question 2

What is reason 1 why action potentials can only travel in one direction

Answer 2

Synaptic vesicles full of neurotransmitters are only located in presynaptic neurone

Question 3

What is reason 2 why action potentials can only travel in one direction

Answer 3

Receptors for the neurotransmitter are only located on the postsynaptic membrane

Question 4

Neurones have synapses with …. other neurones

Answer 4

Many (often neurone will receive signals from many pre-synaptic neurones)

Question 5

What is required for an action potential to be triggered

Answer 5

Multiple action potentials from multiple presynaptic neurones

Question 6

What is spatial summation

Answer 6

Where multiple EPSPs from multiple presynaptic neurones are added together in a post-synaptic neurone

Question 7

What is temporal summation

Answer 7

Multiple EPSPs from a single presynaptic neurone are added together in a postsynaptic neurone over time

Question 8

What occurs if there are lots of action potentials arriving in a short space of time

Answer 8

Lots of neurotransmitters will be released

Question 9

What will happen to neurotransmitters being released due to temporal summation

Answer 9

Neurotransmitters will stay in the synaptic cleft for a long time since it can’t be broken down quickly enough.

Question 10

What is the result of the neurotransmitters building up in the synaptic cleft

Answer 10

Greater depolarisation of the postsynaptic membrane