Exam 2

Question 1

A single action potential in a presynaptic neuron is usually enough to get a post-synaptic cell to fire an action potential. (true/false)

Answer 1

False

Question 2

At current resting membrane potential, the current due to sodium flux is equal to the negative of the current due to potassium flux (assuming the only permeable ions are sodium and potassium). (true/false)

Answer 2

True

Question 3

Second messengers tend to remain active in a cell long after production or activation. (true/false)

Answer 3

False

Question 4

The excess negative charge inside cells is lined up next to the plasma membrane. (true/false)

Answer 4

True

Question 5

The voltage-gated potassium, channel is required for a neuron to repolarize during the action potential. (true/false)

Answer 5

False

Question 6

At the top of the action potential the membrane is most permeable to which ion?

Answer 6

Sodium

Question 7

The properties of which channel causes the absolute refractory period?

Answer 7

Voltage-gated sodium channel

Question 8

The properties of which channel causes the relative refractory period?

Answer 8

Voltage-gated potassium channel

Question 9

What causes the inactivation of the voltage-gated sodium channel to close?

Answer 9

Depolarization

Question 10

What causes the voltage-gated potassium channel to close?

Answer 10

Repolarization/Hyperpolarization

Question 11

Which type of neurons are usually longer in the parasympathetic system?

Answer 11

Pre-ganglionic Neurons

Question 12

Which type of synapses leads to faster effects in the post-synaptic cell?

Answer 12

Electrical synapses

Question 13

If the membrane potential is at a stead -55 mV and the membrane is only permeable to sodium and potassium, then what happens to the amount of sodium entering versus the amount of potassium leaving?

Answer 13

The same amount of sodium is entering the cell as potassium leaving

Question 14

What happens to a neuron when opening sodium channels?

Answer 14

Depolarization

Question 15

Where are voltage-gated sodium channels concentrated in myelinated axons?

Answer 15

Nodal Membrane

Question 16

What causes the voltage-gated sodium channel to open?

Answer 16

Depolarization

Question 17

Which would have the greatest effect on resting membrane potential:

• Changing extracellular potassium concentration
• Changing extracellular sodium concentration

Answer 17

Changing extracellular potassium concentration

Question 18

Most excitatory post-synaptic potentials are due to the opening of what channel?

Answer 18

Non-specific cation channels

Question 19

Which division of the nervous system is also called the craniosacral division?

Answer 19

Parasympathetic nervous system

Question 20

What neurotransmitter binds to a1 receptors?

Answer 20

Epinephrine/Norepinephrine

Question 21

What cells are responsible for making cerebrospinal fluid?

Answer 21

Ependymal Cells

Question 22

What receptor is the M2 receptor?

Answer 22

Gi protein-coupled receptor

Question 23

Post-ganglionic sympathetic neurons primarily release which neurotransmitter?

Answer 23

Norepinephrine

Question 24

Pre-ganglionic parasympathetic neurons release what neurotransmitter?

Answer 24

Acetylcholine (ACh)

Question 25

What is the primary inhibitory neurotransmitter in the spinal cord?

Answer 25

Glycine

Question 26

Which receptors is on adrenal medulla cells?

Answer 26

Nicotinic receptors

Question 27

Decreasing the concentration of potassium chloride inside a cell would cause the cell...

Answer 27

Depolarize

Question 28

Increasing the extracellular sodium concentration would cause the membrane potential to...

Answer 28

Become more positive

Question 29

Increasing the intracellular concentration of potassium and a non-permeable anion would cause the membrane potential to...

Answer 29

Become more negative

Question 30

What would increasing the concentration of an enzyme do to the rate of reaction for a substrate?

Answer 30

Increase the rate of the reaction at all substrate concentrations

Question 31

If the cell with a resting membrane of -80 mV does not actively regulate chloride concentrations in the cell, what would be the equillibrium potential (in mV) for chloride in this cell?

Answer 31

-80 mV

Question 32

What is the equillibrium potential (in mV) for a monovalent anion that has an intracellular concentration of 330 mM and an extracellular concentration of 33 mM?

Answer 32

``` Eq = (62/-1) log(33/330) Eq = 62 mV ```

Question 33

What are two ways to increase conduction speed in an axon?

Answer 33

Myelinate axons | Increasing axon diameter

Question 34

What is the most effective way of increasing conduction seed in an axon?

Answer 34

Myelinating the axon

Question 35

What cells make myelin in the peripheral nervous system?

Answer 35

Schwann Cells