Chapter 3

Question 1

Effectively isolates the cytosol from the extracellular space

Answer 1

Phospholipid Bilayer

Question 2

Lots of it both in and out of the cell. Unevenly charged (easily dissolves polar molecules)

Answer 2

Water

Question 3

Atoms and molecules with a net electrical charge

Answer 3

Ions

Question 4

Membrane spanning protein molecules that allow ions to flow in/out of cell according to their concentration gradients

Answer 4

Ion Channels

Question 5

Determined by pore size and the amino acid groups that line the pore

Answer 5

Ion selectivity

Question 6

How a channel opens and closes

Answer 6

Gating

Question 7

Movement of ions from an area of high concentration to low concentration

Answer 7

Diffusion

Question 8

Gate is always open

Answer 8

Resting K+ channel

Question 9

Opens (transiently) in response to change in the membrane potential

Answer 9

Voltage-gated channel

Question 10

Opens (closes) in response to a specific extracellular neurotransmitter

Answer 10

Ligand-gated channel

Question 11

Opens (closes) in response to a specific intracellular molecule

Answer 11

Signal-gated channel

Question 12

Enzymes that use energy (ATP) to transport ions across the membrane (commonly against ion gradients)

Answer 12

Ion Pumps

Question 13

Describes the relationship between voltage, current, and resistance in any DC electrical unit

Answer 13

Ohm’s Law

Question 14

Membrane permeability of K is ___ greater than Na

Answer 14

40 times

Question 15

Making the membrane less negative

Answer 15

Depolarization

Question 16

Making the membrane more negative

Answer 16

Hyperpolarization

Question 17

Protects neurons against too much extracellular K+

Answer 17

Astrocytes

Question 18

Moves K+ through the cytoplasm and through gap junctions with other astrocytes to regulate extracellular K+

Answer 18

Potassium buffering

Question 19

Tightly regulates how much K+ goes into the extracellular fluid

Answer 19

Blood Brain Barrier

Question 20

Conveys information over long distances. Reversal of charge relative to extracellular space

Answer 20

Action Potential

Question 21

Action potential travels in one direction, down axon to the axon terminal

Answer 21

Orthodromic

Question 22

Back propagation AP

Answer 22

Antidromic

Question 23

Typical conduction velocity of action potential

Answer 23

10 m/sec

Question 24

Typical length of action potential

Answer 24

approx. 2 msec

Question 25

Facilities current flow, with voltage-gated sodium channels concentrated at nodes

Answer 25

Myelin

Question 26

Action potential jumping from node to node

Answer 26

Saltatory Conduction

Question 27

The thick the axon the ___ the conduction

Answer 27

faster