Action Potential and Synapses Flashcards
What is Equilibrium Potential?
Where the area across the neuron is equal (no gradient = no signal sent)
What is membrane potential?
Permeability of membrane to different ions set by electrochemical gradient
What is action Potential?
wave transient depolarisation that travels down the axon
What are Ion channels?
Selectively open and close for different ions in response to changes in membrane potential
What is threshold potential?
the minimum charge needed for an action to occur
What are the main stages of the electrical wave?
1) Threshold potential reached
2) Depolarisation
3) Repolarisation
4) Hyperpolarisation
5) Refractory period
6) Resting potential reached
What occurs in Depolarisation?
Sodium channels open and Na+ flows in via channels
What occurs in Repolarisation?
Voltage gated potassium channels open to allow K+ to flow out
What occurs in Hyperpolarisation?
re-balancing of ions inside and outside of the cell
What is hyperpolarisation also known as?
A refractory period
What effect do Myelin sheaths have on AP?
insulate axons - less charge cost, ap jumps between nodes of ranvier, and fewer ion movement and ATP for higher efficiency
What do excitatory neurotransmitters do?
opens channels, depolarises the post-synaptic neuron, making responses more likely to fire
What do inhibitory neurotransmitters do?
opens channels, hyperpolarises post-synaptic neuron, making responses less likely to fire
What occurs in the post-synaptic cell to reach AP?
Dendrites receive neurotransmitters and the soma then ‘decides’ if an AP is fired
