physiology

Question 1

process of the chemical synapse

Answer 1

action potential arrives at axon terminal
voltage gated calcium channels open, sodium enters the axon terminal
sodium causes synaptic vesicles to release neurotransmitters by exocytosis
neurotransmitters diffuse across the synaptic cleft and binds to the specific receptors on the post synaptic membrane
this then opens the ion channels, resulting in graded potentials
the neurotransmitter effects are terminated via reuptake, degradtion or diffusion away from the synapse

Question 2

process of the action potential

Answer 2

1. resting state
   leaky channels open
   gated channels closed
   voltage is -70mV
2. depolarisation
   gated channels open, sodium enters
   voltage is -55mV and rising
3. repolarisation
   sodium gated channels close, potassium channels open
   no more sodium enters
   voltage reached +30mV
4. hyperpolarisation
   excess potassium leaves
   voltage goes to -75mV