5.3.6(Synapses 2)

State the 2 methods in which neurones can communicate with other synapses

• Convergence

• Divergence

Describe what is meant by convergence and divergence

• Convergence: when 1 neurone connects and communicate to multiple other neurones

• Divergence: when multiple neurones connect and communicate with 1 neurone

Describe what is meant by the term summation

• The amplification of impulses by the combining of multiple EPSPs to increase the depolarisation until the threshold potential is reached

State the 2 types of summation

• Temporal summation

• Spatial summation

Describe what is meant by temporal summation

• A single presynaptic neurone releases neurotransmitters into synapse

• The neurotransmitter accumulates, threshold is reached and an AP is generated in the post synaptic neurone

  • Important in reflex arcs

Describe what is meant by spatial summation

• Many neurones release neurotransmitters into a single synapse

• Together they corss the threshold potential and initiate an AP at the post synaptic neurone

Describe how the generation of an AP in the post synaptic neurone can be inhibited

• inhibitor post-synaptic potentials(IPSPs)- They reduce the effect of summation and prevent an action potential from generating in the post synaptic neurone

• Inhibiting the release of neurotransmitters

• Blocking sodium/potassium ion channels on the post synaptic neurone

Describe the importance of EPSPs

• Can be combined during summation to warn us of danger by spatial summation

• Can be used to prevent the effect of IPSP