Chapter 1.2

Question 1

Resting potential

Answer 1

Difference in voltage in cell

Prepares neuron to respond rapidly

Question 2

Concentration gradient

Answer 2

Difference in distribution of ions across membrane; Ion moves to even out the number of ions inside/outside the membrane

Sodium moves in; K moves out

Question 3

Electrostatic gradient

Answer 3

Opposites attract & negative ions pulled towards positive ones

Inside of cell is negative and sodium is positive, so Na pulled in

Question 4

Depolarization

Answer 4

Inside of cell becomes less negative

Question 5

Hyperpolarization

Answer 5

Inside becomes more negative

Question 6

Temporal summation

Answer 6

Sum of successive EPSP’s from a single neuron at the same TIME

Repeated stimuli over a short period of time produces stronger response

Question 7

Spatial summation

Answer 7

Synaptic input from SEVERAL LOCATIONS can have a cumulative effect and trigger a nerve impulse

Question 8

Action potential

Answer 8

A big stimulus beyond the threshold that produces a big response

Question 9

Voltage gate

Answer 9

Proteins that regulate Na and K; permeability depends on voltage difference across membrane

Question 10

Absolute refractory period

Answer 10

Period immediately following the firing of a neuron when it cannot be stimulated no matter how great a stimulus applied

Sodium channels close

Question 11

Relative refractory period

Answer 11

Period shortly after firing of a neuron when a greater than normal stimulus can stimulate a second response

Question 12

All-or-none law

Answer 12

The amplitude and velocity of an action potential are independent of the intensity of the stimulus as long as the stimulus reaches threshold

Question 13

Propagation of the action potential

Answer 13

The transmission of an action potential down an axon

Begins at axon hillock and is generated and regenerated down the axon

Question 14

Action potential process:

Answer 14

1. Axon reaches threshold, Na & K channels open
2. Na ions rush into axon (depolarization)
3. Positive charge flows down axon and opens Na channels at each point
4. At peak of AP, Na channels close
5. K ions flow out
6. K channels close

Question 15

Saltatory conduction

Answer 15

Describes AP jumping from node to node

Occurs in myelinated axons
Conserves energy
More rapid

Question 16

Multiple schlerosis

Answer 16

Immune system attacks myelin sheath, so action potentials die out between one node and the next

Causes poor motor coordination & vision impairment

Question 17

Local neurons

Answer 17

Small neurons without an axon that exchange info only with closest neighbors

Don’t follow all-or-none law
Potential gradually decays as it travels

Question 18

Post synaptic potential

Answer 18

Ligand-gated (chemically gates)
Decremental - dendrites farther from axon hillock lose amplitude
Goal to trigger action potential

Question 19

Autoreceptors

Answer 19

Receptor located on presynaptic terminal of neuron

Tracks amount of neurotransmitter being fired

Question 20

Flexor muscles

Answer 20

Draw an extremity toward trunk of body

Question 21

Extensor muscles

Answer 21

Move an extremity away from body

Question 22

Spontaneous firing rate

Answer 22

Action potentials triggered by synapses that are weakly or erroneously connected to neuron

Question 23

Polarization/electrical gradient

Answer 23

A difference in the electrical charge between inside and outside of cell