How Nerves Work 2 Flashcards Preview

Science for Medicine > How Nerves Work 2 > Flashcards

Flashcards in How Nerves Work 2 Deck (14)
Loading flashcards...
1
Q

Why do neurons exist?

A

To send electrical signals.

2
Q

What are the 3 types of electrical potentials and give their description?

A

Action - transmit signals over long distances
Graded - decide when action potentials should be fired
Resting Membrane Potential - helps cell be ready to respond

3
Q

What is the resting membrane potential of a cell?

A

-70mV (negative relative to the rest of the cell)

4
Q

Describe the sodium/potassium pump.

A

It spreads across the cell membrane and uses ATP to transfer sodium out of the cell and potassium in.

5
Q

Describe leaky potassium ion channels.

A

They allow potassium out of the cell down the concentration gradient.

6
Q

What happens as the cell becomes more negative due to leaky potassium ion channels?

A

The cell draws potassium ions back in which is called the electrical gradient.

7
Q

What is Nernst’s rule?

A

The equilibrium potential is the membrane potential at which the electrical gradient is exactly equal and opposite to the concentration gradient.

8
Q

What is the equation for Nernst’s rule?

A

E = RT log10 [ion]o

zF [ion]i

9
Q

What do R, T, z and F stand for in the Nernst’s rule equation?

A
R = gas constant
T = absolute temperature (K)
z = valence of the ion
F = faraday constant
10
Q

What does a higher potassium concentration outside of the cell mean for the concentration gradient?

A

It means the concentration gradient will be smaller which will cause the cell to depolarise.

11
Q

Why can too much potassium kill you?

A

The heart doesn’t have a blood barrier to protect it from the change in the resting membrane potential.

12
Q

What are the ion concentrations inside of the cell for potassium, sodium and chlorine?

A

140
15
10

13
Q

What are the ion concentrations outside of the cell for potassium, sodium and chlorine?

A

5
150
110

14
Q

What is Goldman’s Equation?

A

Vm = RT log10 Pk [K+]o + PNa [Na+]o + PCl [Cl-]o

F Pk [K+]i + PNa [Na+]i + PCl [Cl-]i