MCP 31: Synaptic Physiology

Question 1

EPSP

Answer 1

excititory post-synaptic potential, uses glutamate as a NT, synapses onto dendritic spines

Question 2

glutamate receptors

Answer 2

located on dendritic spines

Question 3

IPSP

Answer 3

inhibitory post synaptic potential, uses GABA and glycine as NT, synapses onto axon hillock

Question 4

temporal summation

Answer 4

larger depolarization occurs when two AP reach the synapse at the same time; regulated by the time constant

Question 5

spatial summation

Answer 5

action potentials from two distinct neurons in close proximity reach the neuron at the same time, regulated by the space constant

Question 6

quantal content

Answer 6

average number of vesicle released from activation of a presynaptic nerve

Question 7

quantal size

Answer 7

the response to one vesicle, or average mini amplitude. There are three factors that can control quantal size:

1. Concentration of the NT in the vesicle
2. Number of postsynaptic receptors
3. How much current each receptor can carry

Question 8

MINI

Answer 8

miniature spontaneous synaptic event

Question 9

characteristics of NMJ

Answer 9

acetocholine breaks down ACh, tons of ACh receptors, only excitatory, large safety factor, innovated by one motor neuron

Question 10

characteristics of CNS

Answer 10

no enzyme to break down NT, fewer NT receptors, inhibitory and excitatory, no safety factor so lots of failures, can be innervated by multiple presynaptic neurons, synaptic vesicles release few NT molecules

Question 11

size of cells and Rm

Answer 11

larger cells have lower Rm and thus lower temporal summation than smaller cell

Question 12

glutamate receptor

Answer 12

tetramer with 4 membrane spanning domains