neurons - synapses and signal transduction

Question 1

chemical synapses

Answer 1

• electrical current is carried from neuron to neuron via chemical signals (neurotransmitters and neuropeptides)

Question 2

ionotropic receptors

Answer 2

• neurotransmitters bind and cause the opening of channels
• direct opening of channels
  1. axon propagates signal down to the axon terminal
  2. calcium influx causes vesicles to move towards the pre-synaptic membrane
  3. once fused with the membrane, vesicles will dump neurotransmitters into the synaptic cleft
  4. bind to ligand gated channels and cause polarizing event

Question 3

metabotropic receptors

Answer 3

• neurotransmitters bind to g protein coupled receptors
• signal cascade that eventually results in opening and closing of ion channels in the membrane
• slower onset but lasts longer than the other one

Question 4

4 classes of neurotransmitters

Answer 4

• amino acids (glutamate)
• biogenic amines (dopamine and serotonin)
• neuropeptides (endorphins)
• gases (nitric oxide)

Question 5

electrical synapses

Answer 5

• no chemicals requires, faster but less modifiable because it’s dedicated
• can speed things up for dedicated line of communication
• gap junctions in between neurons allow for direct transfer of action potentials across membranes