C11 9-11

Question 1

Energy

Answer 1

capacity to do work

Question 2

potential energy

Answer 2

stored energy - a concentration or electrical gradient across the plasma membrane

Question 3

kinetic energy

Answer 3

energy of motion - movement of ions from great to lesser concentration or movement ions (charged particles) to ions of opposite charge

Question 4

Ions

Answer 4

charged particles - distribution of charged particles are key to nervous function, opposite charges attract and it takes energy to separate them

Question 5

Cations

Answer 5

positively charges particles - Na+, K+, Ca2+

Question 6

Anions

Answer 6

negatively charged particle - Cl-, most proteins, ATP phosphate

Question 7

Voltage

Answer 7

measure of the amount of difference in electrical charge between two points call the potential difference

Question 8

Current

Answer 8

flow of electrical charge or movement of charged particles from point to point.
Dependent on voltage and resistance.
Current = voltage/resistance

Question 9

Apply the concepts of voltage, current and resistance to neurons.

Answer 9

Voltage = the difference between charge potential on the inside and outside of the plasma membrane.  Current = generated when either + or - charged ions cross the plasma membrane.  
Resistance = The plasma membrane offers resistance, and the resistance can be altered by opening and closing ion channels

Question 10

Pump

Answer 10

• Moves sustances against a concentration gradient. -Requires energy.
• Na+/K+ pump, Ca2+ pump

Question 11

Channel

Answer 11

-Moves substances down a concentration gradient. -Channel types: Leakage/nongated, chemically gated/Ligand, voltage gated, mechanically gated.

Question 12

Leakage/nongated channel

Answer 12

Always open, Na+ & K+ channels

Question 13

Chemically gated (Ligand) channel

Answer 13

Open when the appropriate chemical/neurotransmitter/neuromodulator/molecule binds. K+ Na+ Cl- Ca2+

Question 14

Voltage-gated channel

Answer 14

Open in response to a change in membrane potential. Usually in one of two states: open or closed. Na+ K+ Ca2+

Question 15

Why are voltage gated sodium channels unique?

Answer 15

They have two gates - an inactivation gate and an activation gate. Also, they exhibit 3 states: resting, activation, inactivation.

Question 16

Mechanically gated channel

Answer 16

Open when a membrane receptor is physically deformed; found in sensory neurons and respond to things like light or pressure.

Question 17

Resting state - voltage gated sodium channel

Answer 17

Inactivation gate open, activation gate closed

Question 18

Activation state - voltage gated sodium channel

Answer 18

Both inactivation and activation gate open

Question 19

Inactivation state - voltage gated sodium channel

Answer 19

Activation gate open, inactivation gate temporarily closed.

Question 20

What type of pumps and channels in the entire plasma membrane of a neuron?

Answer 20

Leak channels: Na+ and K+

Pumps: Na+/K+

Question 21

What type of pumps and channels in receptive region (dendrites/cell body)?

Answer 21

Chemical (ligand) channels: Cation, K+, Cl-

Some voltage gated channels.

Question 22

What type of pumps and channels in the initial segment (axon hillock)?

Answer 22

Voltage gated Na+ and K+ channels.

Question 23

What type of pumps and channels in the conductive segment (length of axon/axon terminals)?

Answer 23

Voltage gated Na+ and K+ channels.

Question 24

What type of pumps and channels in the transmissive or secretory segment (synaptic knobs)?

Answer 24

Voltage gated Ca2+ channels, Ca2+ pumps.

Question 25

Electrical gradient

Answer 25

Difference in electrical charge between two areas

Question 26

Chemical gradient

Answer 26

Unequal distribution of a substance

Question 27

How is RMP established in a neuron?

Answer 27

RMP is a consequence of differences in K+/Na+ concentrations and plasma membrane permeability to ions. K+ diffuses out of neuron because of chemical gradient, but stops diffusing out because it is pulled back by the electrical gradient. (A-) (-90mV) Na+ diffuses in because of the electrical and chemical gradient . (Changes to -70mV) More K+ leak channels than Na+. Sod-Pot pump plays a small role in establishing

Question 28

How is RMP maintained in a neuron?

Answer 28

Maintenance of RMP is done by Na+/K+ ATPase pump. Continually establishes gradients for both Na+ and K+. 3 Na+ out to 2 K+ in

Question 29

Language of the NS

Answer 29

Graded potentials, Action potentials, Neurotransmitters

Question 30

What contributes to RMP?

Answer 30

Unequal distribution of charge, membrane permeability

Question 31

Resting membrane potential

Answer 31

The voltage that exists across the plasma membrane during the resting state of an excitable cell.

Question 32

What substances are found inside the neuron?

Answer 32

Negative phosphate ions found in ATP Negatively charged proteins K+

Question 33

What substances are found in interstitial fluid?

Answer 33

Na+ | Cl- (chloride)