Class 7: Intraneuronal Communication and Synapses

Question 1

Describe chemical neurotransmission in chronological order. Begin with an action potential at the pre-synaptic axon terminal and end with a graded potential at the postsynaptic membrane.

Question 2

Explain the mechanism by which the opening and closing of ligand-gated ion channels is regulated.

Question 3

Define excitatory postsynaptic potential (EPSP) and inhibitory postsynaptic potential (IPSP).

Question 4

Explain why postsynaptic potentials are transient. What terminates the action of the neurotrasmitter on the postsynaptic cell?

Question 5

Draw 4 vertically aligned graphs to illustrate what happens to the following parameters vs. time at an excitatory synapse after the arrival of a single action potential at a presynaptic axon terminal:

1. [Ca2+] in the presynaptic axon terminal vs. time
2. [Neurotransmitter] in the synaptic cleft vs. time
3. # of receptors on the postsynaptic membrane that are bound by neurotransmitter vs. time
4. Postsynaptic membrane potential vs. time

Repeat this but consider what happens when two action potentials arrive within just a few msec of each other (after the refractory period).