How Nerves Work 2

Question 1

Do hormones or nerves produce faster responses?

Answer 1

Nerves

Question 2

How is the electrical signal of nerves made?

Answer 2

Through the three membrane potentials:

Resting membrane potential

Graded membrane potential

Action potential

Question 3

What is the resting membrane potential responsible for?

Answer 3

Keeps cells ready to respond

Question 4

What is the graded potential responsible for?

Answer 4

Determines whether an action potential should be fired

Question 5

What is the action potential responsible for?

Answer 5

Transmits signals over long distances

Question 6

What is the voltage of the inside of a cell compared to the outside?

Answer 6

-70mV

Question 7

What is responsible for the inside of a cell being -70mV compared to the outside?

Answer 7

Leaky K⁺ channels

Question 8

What is the equilbrium potential?

Answer 8

Membrane potential at which the elctrical gradient is exactly equal and opposite to the concentration gradient

Question 9

The Nernst equation predicts the equilbrium potential, what does this look like?

Question 10

What is 0K in ^oC?

Answer 10

-273^oC

Question 11

What is the equilbrium potential for K⁺?

Answer 11

-90mV

Question 12

How does the blood brain barrier protect the brain from changes in ion concentration?

Answer 12

Cappilaries are especially tight

This is due to astrocytes and tight junctions

Question 13

What are the typical concentrations of important ions in and outside a cell?

Answer 13

K⁺ greater inside

Na⁺ greater outside

Cl^- greater outside

Question 14

What is the equilbrium potential for Na⁺?

Answer 14

+50mV

Question 15

What is the equilbrium potential for Cl^-?

Answer 15

-75mV

Question 16

The goldman equation predicts the equilbrium potential for several ions, what does this look like?

Question 17

Why is the normal resting membrane potential (RMP) -70mV?

Answer 17

Electrogenic nature of the Na⁺/K⁺ pump (3 Na⁺ out and 2 K⁺ in)

Lrge intracellular negatively charged molecules

Question 18

What does depolarising mean?

Answer 18

Takes the cell towards 0V

Question 19

What does overshoot mean?

Answer 19

Polarises in the opposite direction

Question 20

What does repolarise mean?

Answer 20

Polarise in original direction

Question 21

What does hyperpolarise mean?

Answer 21

Greater polarisation in the same direction