CH 1.2 Nerve Impulses

Question 1

What is an important function of the Axon in regards to electrical impulse?

Answer 1

-The axon regenerates it at each point!

Question 2

What are the ranges of speeds than an Axon can transmit information?

Answer 2

less than 1m/s to 100m/s

Question 3

How do messages in the Neuron develop?

Answer 3

-They develop via disturbances of the resting potential

Question 4

How thick is the membrane of a Neuron & what is made of?

Answer 4

8nm

-It is made of 2 layers of phospholipid molecules w/ cylindrical protein molecules embedded in them

Question 5

What does the membrane maintain while its at rest?

Answer 5

-An electrical gradient= polarization= difference of electrical charge between outside & inside the cell

Question 6

How is the electrical potential like inside the membrane?

Answer 6

-It is slightly negative bc of negatively charged proteins inside the cell

Question 7

What is the difference in Voltage?

Answer 7

• AKA Resting potential

- The difference between the inside & outside of the membrane

Question 8

What is the typical Resting Potential?

Answer 8

-70mV inside the membrane

Question 9

What chemicals is the membrane permeable to?

Answer 9

• Water
• Urea
• Oxygen
• Carbon Dioxide

Question 10

What ions can pass through the membrane via Active Transport?

Answer 10

• Sodium
• Potassium
• Calcium
• Chloride

Question 11

What is the Sodium-Potassium Pump?

Answer 11

• AKA type of active transport
• It is a protein complex that repeatedly transports 3 sodium ions OUT that STAY OUT and drawing 2 Potassium ions IN but slowly leak out carrying a positive charge= increases the electrical gradient across membrane

Question 12

Where are sodium ions concentrated at?

Answer 12

-They are mostly concentrated OUTSIDE the membrane

Question 13

Where are potassium ions concentrated at?

Answer 13

-Mostly concentrated INSIDE the membrane

Question 14

What is Potassium subject to?

Answer 14

-It is subject to competing forces bc it is positively charged while the inside of the cell is negatively charged

Question 15

What sustains the membrane’s Polarization?

Answer 15

-The negatively charged proteins in the cell

Question 16

When the membrane is at rest are the sodium ions more concentrated inside or outside the cell?

Answer 16

-They are more concentrated outside the cell

Question 17

When the membrane is at rest, what tends to drive Potassium ions out of the cell?

Answer 17

-The concentration gradient drives out the potassium ions because they are more concentrated inside the cell, therefore, potassium needs to leave in order to create balance

Question 18

What 2 things tend to draw Potassium inside the cell?

Answer 18

-The electrical gradient & the sodium-potassium pump

Question 19

What is the purpose of the Resting Potential?

Answer 19

-It prepares the neuron to respond rapidly

Question 20

What are Action Potentials?

Answer 20

-They are messages sent by axons

Question 21

What is the potential inside the axon when its membrane is at rest?

Answer 21

-It is a negative potential