Action Potentials

• What is an energy transducer

  converts one form of energy to another to generate an impulse
• Are leakage channels open or closed

  constantly open
• what is the typical change in potential difference

  from -70 to +40
• what is the order of an action potential

  stimulus - receptor - coordinator - effector - response
• what is hyper polarisation

  too much potassium influx
• .

  .

  A) depolarisation

  B) sodium

  C) repolarisation

  D) potassium

  
• what is membrane potential

  difference between voltage inside and outside of cell
• what is the typical voltage inside of a cell

  0
• what is the nernst equation

  E= RT.log10/zF (Co/Ci)

  E= equilibrium potential

  Co= extracellular conc of ions

  Ci= intracellular conc of ions

  z= valency of ion e.g Cl- is -1

  R,F= constants

  T= temperature
• what is 20 degrees in RT for nernst equation

  58
• what is 37 degrees in RT for nernst equation

  61
• what is conduction velocity

  speed action potential moves along nerve fibre
• what is it called when action potential jumps between myelinated fibres

  saltatory conduction
• what is the neurotransmitter at a neuromuscular junction

  acetylcholine
• what are the events at a neuromuscular junction

  AP moves to axon terminal

  AP causes opening of Ca2+ channels

  Ca2+ triggers release of acetylcholine

  Diffuses across synaptic cleft and binds with receptors on motor end plate

  Binding causes opening of Na+ channels

  Depolarisation occurs at motor end plate

  Na+ influx initiates AP