Lecture 5

Question 1

Sodium Ion Concentration

Answer 1

ECF: 140mM
ICF:14mM

Question 2

Potassium Ion Concentration

Answer 2

ECF: 4mM
ICF: 140 mM

Question 3

Chloride Ion Concentrations

Answer 3

ECF: 110mM
ICF: 7mM

Question 4

Resting Membrane Potential

Answer 4

about -70mV

Question 5

Factors of Concentration Difference

Answer 5

1. Electrical attraction by fixed anions
   2.Greater permeability to potassium
2. Active transport (na+/K- pump)

Question 6

Nernst Equation

Answer 6

calculates potential differences that would balance ion’s concentration gradient

Question 7

Potassium voltage

Answer 7

-91mV

Question 8

Sodium voltage

Answer 8

+61mV

Question 9

Graded potential

Answer 9

varies directly by intensity of stimulus

Question 10

Action Potentials

Answer 10

All or nothing signal along axon, -55mV

Question 11

Depolarization

Answer 11

membrane potential moves above -70mV

Question 12

Hyperpolarization

Answer 12

membrane potential moves lower than -70mV

Question 13

Absolute Refractory Period

Answer 13

Na+ channels close, no response to stimuli

Question 14

Relative Refractory Period

Answer 14

Na+ channels are closed, K+ channels open to hyperpolarize membrane (membrane must reach threshold again for another action potential)

Question 15

Conduction velocities of Axons depend on:

Answer 15

1. Axon Diameter(larger, faster)
2. Myelin Sheath (myelinated, faster)

Question 16

Ways that neurotransmitters are terminated:

Answer 16

1. Degraded by enzymes on receptor protein
2. Reintegrated into pre-synaptic terminal
3. Diffuses away from synapse, is destroyed in system

Question 17

Excitatory Synapse

Answer 17

neurotransmitter binding brings membrane potential toward threshold

Question 18

Excitatory Postsynaptic Potential (EPSP)

Answer 18

a change in a postsynaptic cell’s membrane voltage that increases the likelihood of an action potential

**A single EPSP cannot trigger AP alone

Question 19

Inhibitory Synapse

Answer 19

Neurotransmitter binding reduces resting membrane potential, hyper polarization

Question 20

Inhibitory Postsynaptic Potential (IPSP)

Answer 20

Hyperpolarization of postsynaptic membrane which inhibits an action potential

Question 21

Temporal Summation(ESPS)

Answer 21

when a single neuron fires repeatedly in quick succession, causing ESPS to summate over time

Question 22

Spatial Summation(ESPS)

Answer 22

multiple presynaptic neurons fire on the postsynaptic neuron at once
combined ESPS may trigger action potential

Question 23

Synaptic Potentiation

Answer 23

Repeated usage of a synapse increases excitation of postsynaptic neuron.

produces larger postsynaptic potential

Question 24

Presynaptic inhibition

Answer 24

Action potential is inhibited when another neuron attaches to the presynaptic axon.

Leads to a decrease amount of neurotransmitter release