2.Synaptic Transmission

Question 1

Describe in chronological order the seven major events that occur during chemical synaptic transmission.

Answer 1

1. Action potential is generated and sent down the axon
   2.Depolarization of the presynaptic terminal
   3.Opening of Vdep Ca2+ channels
   4.Ca2+ induced fusion of vesicles in presynaptic membrane
   5.Binding of transmitter to postsynaptic receptor
2. postsynaptic action: ligand gated channel
3. Termination of transmitter action

Question 2

describe the pathophysiology producing myasthenia gravis, and how it is diagnosed and treated

Answer 2

this is when antibodies are created for the postsynaptic nAch receptor at the neuromuscular junction,
it is diagnosed by a Edrophonium test
it is treated by longer acting cholinesterase inhibitor

Question 3

Describe the term presynaptic and postsynaptic in relation to synaptic transmission

Answer 3

The neuron transmitting the signal is the presynaptic, the neuron receiving the signal is postsynaptic

Question 4

Explain how synaptic activation may elicit excitatory or inhibitory postsynaptic effects

Answer 4

The excitatory postsynaptic effect can happen when depolarization happens whether it be Na entering the cell or K leaving the cell
The inhibitory postsynaptic effect happens when hyperpolarization happens

Question 5

Define temporal summation

Answer 5

The same excitatory synapses activated in rapid succession

Question 6

Define spatial summation

Answer 6

Excitatory synapses from different sources

Question 7

Explain how temporal and spatial summation are needed to bring a postsynaptic neuron to threshold. Explain how this is different than transmission at a neuromuscular synapse.

Answer 7

For the temporal summation, when its excited in rapid succession, it leads to the summation of the depolarization, so the threshold for an AP is reached
For the spatial summation, when the synapses are activated together, they produce enough depolarization to reach threshold for an AP
in neuromuscular synapse its just one action potential in the motoneuron than leads to contraction of the muscle fiber.

Question 8

Describe the difference between ionotropic and metabotropic postsynaptic effects

Answer 8

Ionotropic is when the receptor is linked to an ion channel
Metabotropic is when the receptor is linked to a G protein

Question 9

Name the main excitatory transmitter used by the nervous system and 2 inhibitory neurotransmitter.

Answer 9

Main excitatory neurotransmitter-Glutamate
Main inhibitory neurotransmitter-Glycine, GABA