Lecture 3

Question 1

To prevent transmission at a synapse you could: (choose all that apply)
A. Prevent neurotransmitter exocytosis with a drug
B. Block post-synaptic receptors with a drug
C. Destroy post-synaptic receptors via an autoimmune reaction
D. Block voltaged-gated Ca2+ channels with a drug

Answer 1

All of the above

Question 2

Which way do ions move during an EPSP?

Answer 2

+ ions enter the cell

Question 3

Which way do ions move during an IPSP?

Answer 3

+ moves out of the cell, - ions move into the cell

Question 4

What is summation?

Answer 4

All of the synapses (EPSPs + IPSPs) added together

Question 5

Would an action potential be generated in the following scenario?
500 EPSP
100 IPSP

Answer 5

Yes, because there is an overall positive charge (+400) and therefore it is stimulating and an AP would be generated

Question 6

Would an action be generated in the following scenario?
250 EPSP
250 IPSP

Answer 6

No, because the overall charge is 0

Question 7

T/F Overall when we have a correctly functioning nervous system, the charges are in balance

Answer 7

True

Question 8

What determines if its an EPSP or IPSP?

Answer 8

The receptor

Question 9

Neurotransmitter receptors are either _______ or _______

Answer 9

Stimulatory (+ ions enter cell) or Inhibitory (+ ions leave cell, - ions enter cell)

Question 10

What are the two structure types of neurotransmitter receptors?

Answer 10

• Directed-gated ion channel

- Indirect-gated/second messenger

Question 11

Where is the receptor located in a direct-gated ion channel?

Answer 11

Directly on the ion channel

Question 12

What is the sequence of events for a direct-gated ion channel?

Answer 12

Binding –> channel opens –> ions flow

Question 13

Where does a neurotransmitter bind on an indirect-gated ion channel?

Answer 13

It binds to a receptor that has a G-protein on it.
Once the neurotransmitter binds, part of the G-protein breaks off (2nd messenger) and binds to a different receptor that is attached to a ion channel.

Question 14

What is the sequence of events for a indirect-gated ion channel?

Answer 14

Neurotransmitter binds –> changes G-protein, subunit detaches –> subunit binds to ion channel –> channel opens –> ions flow

Question 15

How is the brain able to change based on experience?

Answer 15

Neural plasticity

Question 16

What happens when a neurotransmitter disengages from a receptor?

Answer 16

1. It is dissolved by enzymes OR

2. Pre-synaptic re-uptake (it gets reused in the same process, some drugs can inhibit this)

Question 17

What happens when if a drug increases the number of neurotransmitters? What is this called?

Answer 17

• The nervous system pulls receptors in –> less receptors = decreases effect
• Receptor Down Regulation

Question 18

What happens if a drug decreases the amount of neurotransmitters? What is this call?

Answer 18

• The nervous system increases the number of receptors to increases the likelihood of a NT binding –> supersensitization
• Receptor Up Regulation

Question 19

What are the 5 different types of Glial Cells?

Answer 19

1. Astrocytes
2. Oligodendroglial cells
3. Microglia
4. Ependymal cells
5. Schwann cells

Question 20

Which glial cells are part of the CNS? PNS?

Answer 20

CNS = astrocytes, oligodendroglial cells, microglia and ependymal cells
PNS = schwann cells

Question 21

Which cells impair axon regeneration?

Answer 21

Oligodendroglial cells (CNS unable to repair axons)

Question 22

Which cells promote axon regenerations?

Answer 22

Schwann cells (PNS able to repair axons)

Question 23

What is the role of the myelin sheath? What cells make it up?

Answer 23

• Insultes axons
• Saltatory conduction (speeds AP transmission)
• Schwann cells