synapses 2 Flashcards
what is summation
occurs when the effects of several excitatory post-synaptic potentials are added together
what is the all or nothing response
once action potential starts, it is conducted along the entire neurone
if a stimulus is intense what happens to the action potential
it becomes more frequent
what is the main role of a synapse
connect two neurones, so that a signal can be passed across.
what does an EPSP stand for
excitatory post synaptic potential
describe an EPSP
when a small number of acetylcholine diffuse across the cleft produces a small depolarisation in the post synaptic membrane
will one EPSP cause an action potential
this will not be sufficient enough to cause an action potential in the post synaptic neurone
when several EPSP’s combine to increase membrane depolarisation and reach threshold what is this called
summation
what are the two types of summation
temporal
spatial
what is temporal summation
when one presynaptic neurone generates several action potentials to generate threshold
what is spatial summation
several different pre synaptic neurones, generate multiple different action potentials to reach threshold in the post synaptic neurone
what does IPSP stand for
inhibitory post synaptic potentials
what do IPSP do
reduce the effect of summation and prevent action potential occurring in the post synaptic neurone
how are IPSP produced-
cl- ions on the post synaptic membrane, neurotransmitter bind to receptor on cl- channel
this causes the channels to open and cl- to enter the post synaptic membrane
hyperpolarises the neurone (more negative than usual)
makes it difficult to produce action potential
what is the different between the excitatory or inhibitory synapse
inhibitory synapse have chloride channels
where as excitatory synapses have sodium channels.
