Lecture 2.1

Question 1

Where on the neuron is the site where voltage gates are most concentrated?

Answer 1

Axon Hillock

Question 2

Where on the neuron are voltage gates located?

Answer 2

Axon Hillock, axon, and axon terminal region

Question 3

What are the three features of an action potential?

Answer 3

1. All or none
2. Self Propagating
3. No Summation

Question 4

____ voltage gates open, causing rapid DEPOLARIZATION

Answer 4

Na+

Question 5

What are the two Na+ voltage gates?

Answer 5

1. Activation gate

2. Inactivation gate

Question 6

During rest, activation gate is _____ and inactivation gate is _____.

Answer 6

During resting, activation gate is CLOSED and inactivation gate is OPENED.

Question 7

_____ voltage gates open, causing REPOLARIZATION

Answer 7

K+

Question 8

What are the two types of refractory periods?

Answer 8

1. Absolute refractory period

2. Relative refractory period

Question 9

What is absolute refractory period?

Answer 9

A period of time during the action potential when membrane is insensitive to additional stimulus which prevents summation. (Due to sodium voltage gates being on a timer)

Question 10

What is the relative refractory period?

Answer 10

The period of time during repolarization and hyperpolarization when an action potential can be generated if an exceptionally strong stimulus is applied to the membrane.

Question 11

What is continuous conduction?

Answer 11

Conduction of action potentials along unmyelinated axons causes the entire length of the axon to go through the process of repolarization and depolarization.

Question 12

What is saltatory conduction?

Answer 12

Conduction of action potentials occurs only along exposed portions of the axon in myelinated fibers at the nodes of Ranvier.

Question 13

At -70mV, there are (many/few) K+ ions and (many/few) Na+ ions on the OUTSIDE and many/few) K+ ions and (many/few) Na+ ions on the INSIDE

Answer 13

At -70mV, there are FEW K+ ions and MANY Na+ ions on the OUTSIDE and MANY K+ ions and FEW Na+ ions on the INSIDE

Question 14

At +30mV, there are (many/few) K+ ions and (many/few) Na+ ions on the OUTSIDE and many/few) K+ ions and (many/few) Na+ ions on the INSIDE

Answer 14

At +30mV, there are FEW K+ ions and FEW Na+ ions on the OUTSIDE and MANY K+ ions and MANY Na+ ions on the INSIDE

Question 15

At less than -70mV, there are (many/few) K+ ions and (many/few) Na+ ions on the OUTSIDE and many/few) K+ ions and (many/few) Na+ ions on the INSIDE

Answer 15

At less than -70mV, there are MANY K+ ions and FEW Na+ ions on the OUTSIDE and FEW K+ ions and MANY Na+ ions on the INSIDE

Question 16

What is the maximum mV that an action potential can ever reach, in other words, what is the upper limit of depolarization? why?

Answer 16

+63mV because this is sodium’s equilibrium potential

Question 17

What is the minimum mV that an action potential can reach in hyperpolarization?

Answer 17

-94mV