The Nerve Impulse

Question 0

Any Gradient (inequality) between the chemicals inside vs. outside the cell will “seek”:

Answer 0

an equilibrium

Question 1

To understand how Neurons “communicate” we need to recognize…

Answer 1

Nature seeks a balance

Question 2

Concentration Gradient

Answer 2

• molecules in area of greater concentration will DIFFUSE to area of lesser concentration

Question 3

Electrical Gradient

Answer 3

• positively charged particles will move away from other positive (& toward negative) and negative will move from negative (& towards positive) = ELECTROSTATIC PRESSURE

Question 4

In Neurons, the distribution of charged particles (ions w/extra proton or electron) in/outside the cell is controlled by….

Answer 4

• recall how the Blood-Brain Barrier restricts what chemicals can move from bloodstream into brain
• membrane potential = difference in charge in/outside cells, measured in mV using microelectrodes

Question 5

Key Ions

Answer 5

• sodium: Na+
• potassium K+
• Calcium Ca++
• Chloride Cl-

Question 6

Resting Potential of most Neurons

Answer 6

• 70 mV

- less positive inside/more positive outside

Question 7

Sodium-Potassium Pump

Answer 7

• energy requiring process
• grabs sodium inside the cell
• re-establishing resting potential (-70 mV)
• actively transports 3 Na + and 2 K+ in