action potential

Question 1

Differentiate between an action potential and a graded potential.

Answer 1

Action potential is brief reversal of membrane potential with a total change in voltage from -70mV to +30mV – all or nothing (can’t go backwards)

Graded potential is a short lived change in membrane potential (can be depolarized -membrane potential becoming more positive-, hyperpolarized -membrane potential becoming more negative), or repolarized) stimulatory stimulus

Question 2

Understand all events that occur during an action potential.(Ligand/chemical channels, threshold, voltage gated Na+, K+, Cl- and Ca++ channels).

Answer 2

Ligand/chemical channels: only open when appropriate neurotransmitter binds to the protein

Threshold: occurs when graded potential becomes more positive than 20mV – change in permeability of membrane

Voltage gates/channels: open and close at the axon hillock in response to membrane potential

Question 3

Why does the inside become more positive during depolarization/negative during repolarization?

Answer 3

Because There is more sodium going into the cell during depolarization and during repolarization
the sodium is leaving the cell.