Nerve conduction - membrane or resting potential

Question 1

Diffusion (concentration) force

Answer 1

Molecules go from areas of high concentration to low until they are evenly distributed throughout the medium

Question 2

Electrostatic force

Answer 2

• substances which, when dissolved in water, split apart into two particles each with an opposing electrical charge are electrolytes
• charged particles are ions
• like charged particles repel and opposite charged particles attract
• particles will distribute themselves in a medium until the charged particles are evenly distributed

Question 3

What contain different ions?

Answer 3

Intra and extracellular fluid

Question 4

How is membrane potential produced and what is the charge?

Answer 4

Is produced by balance between diffusion and electrostatic forces -70mV

Question 5

Ions in and outside of the neuron are

Answer 5

COPS:
Chloride(Cl-)
Organic ions(A-)
Potassium(K+)
Sodium (Na+)

Question 6

Chloride

Answer 6

negatively charged ion (Cl-) highly concentrated outside neuron. Diffusion force pushes it into the neuron, but since the internal membrane is negatively charged electrostatic force pushes it out. The balance of these forces results in greatest concentration of Cl- outside

Question 7

Organic ions

Answer 7

negatively charged (A-) present only on inside of neuron. Membrane is impermeable to it so it stays inside neuron and contributes to negative charge on internal surface of membrane.

Question 8

Potassium

Answer 8

positively charged ion (K+) highly concentrated inside neuron. Diffusion force tends to push K+ out of cell, but since outside of membrane is positively charged, electrostatic force pushes it in. The balance of these forces results in greatest concentration of K+ inside

Question 9

Sodium

Answer 9

positively charged ion (Na+) highly concentrated outside neuron. Diffusion force pushes it into neuron. Because the internal membrane is negatively charged electrostatic force attracts it into the neuron

• high concentration of Na+ outside neuron is maintained by two factors:
  a. membrane is not very permeable to Na+ so only a small amount is able to “leak” into the neuron
  b. protein molecules in the membrane called “sodium-potassium transporters” (pump) remove the Na+ that leaks in and the K+ that leaks out
  c. sodium-potassium transporters are made up of proteins that actively transport these ions
  d. Na+ - K+ pumps consume ~ 40% of neurons energy