Lecture 18/19- Glia/Electrical Properties of Neurons

Question 1

What three types of glia are in the CNS?

Answer 1

Astrocytes, Oligodendrocytes, Microglia

Question 2

What is the function of astrocytes?

Answer 2

Extracellular homeostasis

Maintains K+/neurotransmitter concentrations in the extracellular space

Question 3

What is the function of oligodendrocytes?

Answer 3

Myelination of conductive region

Question 4

What is the function of microglia?

Answer 4

Long term maintenance of neurons

Question 5

What type of glia is in the PNS?

Answer 5

Schwann cells

Question 6

What is the function of Schwann cells?

Answer 6

Supports neuron regrowth

Question 7

Is the CNS or PNS glia better at regrowing damaged neurons?

Answer 7

PNS

Question 8

True or false: The CNS is good at regrowing damaged neurons

Answer 8

FALSE

Question 9

At rest, which ion channel is dominant in plasma membrane potential?

Answer 9

Potassium channels (-80 mv)

Question 10

Not at rest, which ion channel is dominant in plasma membrane potential?

Answer 10

Sodium channels (-58 mv)

Question 11

What is the definition of equilibrium in respect to membrane potential?

Answer 11

Probability of K+ going down concentration gradient is balanced by the negative charge keeping the K+ ions from leaving

Question 12

Is there a higher concentration of K+ or Na+ ions inside the cell?

Answer 12

K+

Question 13

Is there a higher concentration of K+ or Na+ ions outside the cell?

Answer 13

Na+

Question 14

What type of channels are open all the time?

Answer 14

K+ leak channels

Question 15

What does “Mantra” explain?

Answer 15

The membrane potential seeks the equilibrium potential of the dominant permeability OR which ion has more ion channels open… this drags the membrane potential towards the ion’s equilibrium potential

Question 16

What does “threshold” mean?

Answer 16

Equal amounts of K+ and Na+ channels open

Question 17

What does the ball and chain inactivation mechanism do?

Answer 17

The ball enters the open channel and binds to the hydrophobic inner vestibule within the channel. This blockage causes inactivation of the channel by stopping the flow of ions.