Action potential

Question 1

Retinal ganglion cell responses

Answer 1

response from light against dark background, reacts to contrasts

Question 2

Neuron

Answer 2

quiet in resting state

firing in action potential

Question 3

Resting membrane potential

Answer 3

electrode measures potential, inside more -ve outside more +ve

Question 4

ionic basis

Answer 4

K+ higher in cell NA+ higher outside neuron cell

Question 5

electrostatic pressure

Answer 5

disperses positive and negative charges

ions pass through ion channels

Question 6

3 pressures maintain unequal ion distribution

Answer 6

Electrochemical pressure
Concentration gradient
Sodium-potassium pump

Question 7

electrostatic pressure

Answer 7

-ve attracts +ve (cations)

negative charge in cell repels negative charges in cell

Question 8

concentration gradient

Answer 8

ions move from high to low concentration areas

Question 9

sodium- potassium pump

Answer 9

pressure on Na+ to enter cell and K+ to exit

difficult as channels are almost shut but few do pass through

Question 10

Action potential

Answer 10

excitation (-70 - -50mV)
sodium channels open na+ rush in +50 mV
K+ ions rush out
channels close
hyperpolarized

Question 11

Polarized

Answer 11

resting state (-70mV)

Question 12

Depolarized

Answer 12

action potential (+50mV)

Question 13

repolarized

Answer 13

back to -70mV

Question 14

Hyperolarized

Answer 14

drops below -70mV

Question 15

refractory period

Answer 15

absolute - action potential cant happen milliseconds after first
relative - action potential only at high stimulation level

Question 16

transmission

Answer 16

train of action potentials