Neurophysiology

Question 1

Resting potential

Answer 1

Resting membrane potential of a neuron is about -70mV which means that the inside of the neuron is 70mV less than the outside. There are more k and less NA+ inside and more NA+ and less K+ outside

Question 2

Membrane potential

Answer 2

Membrane potential is a potential gradient that forces ions to passively move in one direction: positive ions are attracted by the ‘negative’ side of the membrane and negative ions by the ‘positive’ one

Question 3

Action potential

Answer 3

the voltage sodium channels starts open when depolarizing an begin to allow sodium in, and the cell depolarize.
This increases the feedback loop, when/if the threshold is hit, it will open full and potential fires.

Treshold is depended upon numbers of channels (-40mV > -55mV)

Question 4

Signal transmission between neurons can occur at?

Answer 4

Electrical synapses (gap junctions) or Chemical synapses (cleft)

Question 5

Summation of synaptic potential is dependent on?

Answer 5

Temporal clustering of inputs

spatial clustering of inputs

Stochastic properties of the synapse

Question 6

Ligand gated ion channels

Answer 6

Neurotransmitter bind to channels and alters the permeability of the postsynaptic membrane to certain ions.

Question 7

neurotransmitter receptors

Answer 7

Ligand gated ion channels

metabotropic receptors (G-protein coupled receptors)

Question 8

metabotropic receptors (G-protein coupled receptors)

Answer 8

When ligand binds, an activate intermediate protein called a G-protein. The G-protein can then influence the opening of ion channels, but they can also affect enzymes and initiate signaling cascades within the cell.