Introduction To Synaptic Vesicle Reycling And Neurotransmission

Question 1

Action of action potential at axon terminal (7 bullet points)

Answer 1

1) Action potential arrives at presynaptic terminal
2) Voltage-gated calcium channels open
3) Influx of Ca in the pre-synaptic terminal
4) Synaptic vesicles are released
5) Neurotransmitters are released
6) Binding to specific recetor
7) Depolarisation of post-synaptic membrane

Question 2

For action potential to travel you need

Answer 2

Capacitance high - more charge
Capacitance low - less charge
***?

Question 3

How does myelination determine conduction velocity?

Answer 3

Myelin decrease the capacitance of the axon and restricts the generation of action potentials at nodes of Ranvier
Action potentials are conducted with little decrement and at great speed from one node of Ranvier to the next

Question 4

How fast are the fastest nerve impulses?

Answer 4

~220mph

Question 5

Excitatory postsynaptic potentials (EPSP)

Answer 5

Temporary depolarisation of postsynaptic membrane caused by the flow of positively charged ions into the postsynaptic cell as a result of ligand-sensitive channels opening.

Question 6

When is an EPSP received?

Answer 6

When an excitatory presynaptic cell, connected to the dendrite, fires an action potential

Question 7

How is an EPSP propagated?

Answer 7

Down the dendrite, then is summed with other inputs at the axon hillock

Question 8

Electrical synapses

Answer 8

Local currents flow through gap junctions between neurons
6 connexins from pore channel connects cells; small molecules pass through