Neurons

Question 1

Impulse conduction

Answer 1

• an AP causes an influx of Na+ across the membrane
• reversal is the source of depolarizing current in adjacent membrane
• AP propagates from origin across the rest of the cell
• immediate

Question 2

Vesicle release

Answer 2

• AP current opens Ca++ channels
• triggers cascade of reactions that result in exocytosis
• change is slow because of the enzyme activity

Question 3

Ionotropic effects

Answer 3

• ligand binding opens an ion channel
• causes a post-synaptic membrane potential (PSP)
• 20-40 ms
• cations = EPSP
• Cl- or K+ = IPSP

Question 4

Ionotropic Effect

Answer 4

Ligands are

• Ach
• glutamate
• GABA
• glycine
• receptor determines effect, not the transmitter

Question 5

Metabotropic

Answer 5

• G-protein coupled receptor activated

- increase production or destruction of 2nd messenger

Question 6

Spread of PSPs

Answer 6

• generated in inexcitable membranes by binding of transmitter
• graded potential (not AP)
• passive conduction
• magnitude lost over time

Question 7

PSP summation

Answer 7

• bad cable property
• potential is lost across the membrane

two types:

• spatial
• temporal

Question 8

spatial summation

Answer 8

10-30 EPSP generated at a different synapse

- graded potentials sum at trigger zone and generate an AP