How Nerves work 2

Question 1

<p>Do hormones or nerves produce faster responses?</p>

Answer 1

<p>Nerves</p>

Question 2

<p>How is the electrical signal of nerves made?</p>

Answer 2

<p>Through the three membrane potentials:</p>

<p>Resting membrane potential</p>

<p>Graded membrane potential</p>

<p>Action potential</p>

Question 3

<p>What is the resting membrane potential responsible for?</p>

Answer 3

<p>Keeps cells ready to respond</p>

Question 4

<p>What is the graded potential responsible for?</p>

Answer 4

<p>Determines whether an action potential should be fired</p>

Question 5

<p>What is the action potential responsible for?</p>

Answer 5

<p>Transmits signals over long distances</p>

Question 6

<p>What is the voltage of the inside of a cell compared to the outside?</p>

Answer 6

<p>-70mV</p>

Question 7

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

Answer 7

<p>Leaky K⁺channels</p>

Question 8

<p>What is the equilbrium potential?</p>

Answer 8

<p>Membrane potential at which the elctrical gradient is exactly equal and opposite to the concentration gradient</p>

Question 9

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

Answer 9

Question 10

<p>What is 0K in^oC?</p>

Answer 10

<p>-273^oC</p>

Question 11

<p>What is the equilbrium potential for K⁺?</p>

Answer 11

<p>-90mV</p>

Question 12

<p>How does the blood brain barrier protect the brain from changes in ion concentration?</p>

Answer 12

<p>Cappilaries are especially tight</p>

<p>This is due to astrocytes and tight junctions</p>

Question 13

<p>What are the typical concentrations of important ions in and outside a cell?</p>

Answer 13

<p>K⁺greater inside</p>

<p>Na⁺greater outside</p>

<p>Cl^-greater outside</p>

Question 14

<p>What is the equilbrium potential for Na⁺?</p>

Answer 14

<p>+50mV</p>

Question 15

<p>What is the equilbrium potential for Cl^-?</p>

Answer 15

<p>-75mV</p>

Question 16

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

Answer 16

Question 17

<p>Why is the normal resting membrane potential (RMP) -70mV?</p>

Answer 17

<p>Electrogenic nature of the Na⁺/K⁺pump (3 Na⁺outand 2 K⁺in)</p>

<p>Lrge intracellular negatively charged molecules</p>

Question 18

<p>What does depolarising mean?</p>

Answer 18

<p>Takes the cell towards 0V</p>

Question 19

<p>What does overshoot mean?</p>

Answer 19

<p>Polarises in the opposite direction</p>

Question 20

<p>What does repolarise mean?</p>

Answer 20

<p>Polarise in original direction</p>

Question 21

<p>What does hyperpolarise mean?</p>

Answer 21

<p>Greater polarisation in the same direction</p>