Nerve Signaling (Ch. 19)

Question 1

Acetylcholine

Answer 1

• Excitatory and Inhibitory
• Involved in memory

Question 2

Dopamine

Answer 2

• Mostly inhibitory
• Involved in emotions, mood, and regulating motor control

Question 3

Epinephrine

Answer 3

• Excitatory or Inhibitory
• Acts as a hormone when decreased by sympathetic neurosecretory cells of the adrenal gland.

Question 4

Norepinephrine

Answer 4

• Excitatory and Inhibitory
• Regulates sympathetic effectors
• (in the brain) invoked in emotional responses

Question 5

Gamma-aminobutyric acid (GABA)

Answer 5

• Inhibitory
• Common inhibitory neurotransmitter in the brain

Question 6

Relative Refractory Period

Answer 6

Period when a neuron can be restimulated with a greater than normal stimulus.

Question 7

Depolarization

Answer 7

Point on curve during which Na ions move into the axon.

Question 8

Polarized

Answer 8

State of an unstimulated neuron’s membrane.

Question 9

Repolarization

Answer 9

Point on the curve during which potassium ions begin to move out of the axon.

Question 10

Action Potential

Answer 10

Also called a nerve impulse.

Question 11

Absolute Refractory Period

Answer 11

Period when a neuron cannot be restimulated because it’s sodium gates are open

Question 12

Na/K pump

Answer 12

• Mechanism by which ATP is used to
  move sodium ions out of the cell
  and potassium ions into the cell.
• Completely restores and maintains
  the resting conditions of the neuron

Question 13

Hyperpolarization

Answer 13

• A voltage change that reduces the
  ability of a neuron to conduct an
  impulse.
• The membrane potential becomes
  more negative.

Question 14

Sequence of events for a nerve impulse

Answer 14

1) Neurotransmitters cross the synaptic
cleft and bind to the receptors on the
postsynaptic membrane.
2) The neurotransmitters cause the Na
channels at the excitatory synapses to
open.
3) Sodium ions flood into the neuron and
make it more positive.
- Depolarization
4) Once the inside of the neuron gets to -55,
the action potential travels down the
axon.
5) Calcium comes into the synaptic bulbs to
push the neurotransmitter vesicles out to
the next neuron.
6) Postassium is pumped out of the cell to
make it more negative again.
- Repolarization
7) The inside of the cell becomes extra
negative (-90).
- Hyperpolarization
8) The cell goes back to normal.