chapter 4 concepts

Question 1

membrane potential

Answer 1

difference in electrical charge between the inside and the outside of a cell

Question 2

how is the membrane potential recorded?

Answer 2

• using micro electrodes (intracellular electrodes)

- one in side the neuron and one outside the neuron (in extracellular fluid)

Question 3

main idea of chapter 4 in the textbook

Answer 3

the function of how neurons conduct and transmit electrochemical signals through your nervous system.

Question 4

resting potential

Answer 4

has a steady potential of -70 millivolts. in this case the neuron is polarized

Question 5

ionic basis of a neurons resting potential

Answer 5

salts in neural tissue separate into ions

Question 6

ions

Answer 6

positively and negatively charged particles

na= sodium ions
k=potassium ions

Question 7

distribution of ions in resting neurons

Answer 7

unequal distribution is maintained through ion channels.

more na+ ions outside the cell than inside

more k+ ions inside the cell than outside

Question 8

pressures on NA+ ions to enter the neuron

Answer 8

1) electrostatic pressure
and
2) random motion

Question 9

electrostatic pressure

Answer 9

• opposites attract

- the -70mv charge inside the cell attracts the positively charged NA+ ions into resting neurons

Question 10

random motion

Answer 10

NA+ ions in random motion tend to move down their concentration gradient.
this is because particles in random motion usually become evenly distributed since they are more likely to move from areas of high concentration to areas of low concentration (down the concentration gradient)

Question 11

pressures preventing NA+ ions from entering the neuron

Answer 11

1) voltage-gated ion channels

2) active transporters

Question 12

voltage-gated ion channels

Answer 12

• sodium (NA+) ion channels are closed
• this prevents sodium from entering

potassium (K+) ion channels are open

Question 13

active transporters (requires energy)

Answer 13

mechanisms in cell membranes that transport ions/molecules (sodium-potassium pumps)

Question 14

sodium-potassium pumps

Answer 14

they continually exchange 3 NA+ ions inside the neuron for 2 K+ ions outside the neuron

Question 15

what are the 2 effects of neurotransmitter molecules binding to post synaptic receptors

Answer 15

they depolarize the receptive membrane

and they hyperpolarize the receptive membrane

Question 16

neurotransmitters

Answer 16

chemicals that are released from firing neurons that interact with receptor neurons

Question 17

depolarize the receptive membrane

Answer 17

decreasing the receptive membrane potential from -70 to -67 millivolts

Question 18

hyperpolarize the receptive membrane

Answer 18

increasing the resting membrane potential from -70 to -72 millivolts

Question 19

the effects of polarization are called

Answer 19

post synaptic potentials