Synaptic transmission

• What are two examples of neurotransmitters?

  Dopamine, serotonin
• What are the steps of synaptic transmission?

  1. Neurotransmitter stored in vesicles reach the synapse
  2. Neurotransmitter release + broken down by enzymes
  3. Neurotransmitter bind to receptors
  4. Postsynaptic cell respond by firing a new electrical impulse
  5. Neurotransmitter re-uptake or degradation
• What happens when a neurotransmitter is excitatory?

  This means that the neurotransmitter increases the positive charge of the postsynaptic neuron. This increases the likelihood that the neuron will fire and pass on the electrical impulse. (e.g. adrenaline)
• What happens when a neurotransmitter is inhibitory?

  This means that the neurotransmitter increases the negative charge of the postsynaptic neuron. This decreases the likelihood that the neuron will fire and pass on the electrical impulse. (e.g. serotonin)
• Synaptic transmission

  The process by which neighbouring neurons communicate with each other by sending chemical messages across the gap (synapse) that separates them
• Neurotransmitter

  Brain chemicals is released from synaptic vesicles that relay signals across the synapse from one neuron to another

  Neurotransmitters can be broadly divided into those that perform an excitatory function and those that perform an inhibitory function
• Describe the sympathomedullary pathway (SMP)

  • Hypothalamus detects stress
  • Sympathetic division activated
  • Stimulates adrenal medulla (inner core of the adrenal glands)
  • Releases hormones adrenaline + noradrenaline
  • Body in a state of arousal - heart rate, breathing rate and blood pressure increase, digestive system activity slow down
• What is the 'fight or flight' response?

  The arousal that the sympathomedullary (sympathetic division of ANS and adrenal medulla) pathway leads to
• Evaluation of 'fight or flight' response

  • Evolutionary aspect - because we have evolved from when we were hunters gatherers, fight or flight may not be as useful for understanding modern day stressors, e.g. exams (cognitive factors may be involved)
  • Gender bias - research based on males, females can show 'tend and befriend' response as release of oxytocin (bonding hormones) in females are shown as response to stress
  • Ignores the freeze response, the 'fight or flight' explanation does not take account for all reactions to stress situations