Electrical Signaling

Question 1

Cells specialized to receive, process and transmit information with high fidelity over long distances

Answer 1

Neurons

Question 2

Cells specialized to detect specific environmental cues

Answer 2

Sensory cells

Question 3

Cells that monitor, support and maintain Nervous system function

Answer 3

Glia

Question 4

Cells specialized to receive Neuronal signals and create responses (Generally Non-Neuronal)

Answer 4

Effector cells

Question 5

Two components of a neuron.

Answer 5

Somatodendritic and axonal

Question 6

Specialized sites of excitatory synaptic contact for reception of chemical signals at the synapse

Answer 6

Dendritic spines -

Contain high levels of receptors that convert chemical signals to electrical signals

Question 7

Sites of inhibitory synaptic contact and transmit all synaptic signals to soma

Answer 7

Dendrite Shafts

Question 8

Integrates synaptic signals, generates complex firing rhythms and links neuronal activity to gene expression

Answer 8

Soma

Question 9

initiates signaling down the Axon

Answer 9

Axon Hillock

Question 10

transmits signals in an all-or-none fashion to post-synaptic follower cells

Answer 10

Axon

Question 11

Axonal Terminations - Specialized site for conversion of Electrical Signals into chemical signals that are released onto follower cells

Answer 11

Synaptic bouton -

Contain highly concentrated packets of neurotransmitters in vesicles that are released when Bouton depolarizes.

Question 12

The property of matter that describes how the matter interacts with the Electromagnetic Force is called the…

Answer 12

charge

Question 13

The Potential Energy a charge feels due to its location in an Electric Field is called the

Answer 13

electrical potential

Question 14

The standard reference Electrical Potential from which other potentials are measured is the

Answer 14

Earth’s electrical potential (aka ground)

Question 15

A _____ _____ is generated when + and - charges are separated
across a lipid bilayer

Answer 15

Membrane potential (volts)

Question 16

_____ _____are seen when positive and negative charges are imbalanced, producing a Net Separation of Charges

Answer 16

Electric fields

Question 17

Only if charges are kept from ____ ____ can an electrical potential difference be maintained.

Answer 17

coming together

Question 18

Neuronal Membrane potentials are normally measured to be between ___mV and ____ mV.

Answer 18

-100 mV and +100 mV

Question 19

Standard convention for membrane potential is

Answer 19

(inside potential - outside potential)

Question 20

What are the two membrane potential determinants?

Answer 20

Charge displacement and membrane thickness

Question 21

Thicker membranes show _____(larger or smaller) potential change for the same amount of displaced charge.

Answer 21

larger

Question 22

When stimulated, Neurons, and other excitable cells, can produce rapid, transient changes in membrane potential called:

Answer 22

Action Potentials

Question 23

Neuronal Electrical Signaling involves the regulated movement of Ions across the lipid bilayer through _____ _____

Answer 23

channel proteins

Question 24

T or F. In the presence of a cation, local water orientation is random

Answer 24

FALSE - dipoles dissipate (+) charge over a large area to lower the energy of solvation; interacting waters are called waters of hydration

Question 25

Ions cannot cross the lipid bilayer because they would have to give up their________ to do so. The energetic cost of losing them is too high.

Answer 25

waters of hydration

Question 26

P(ore)-Loops channels

Answer 26

- Highly selective cation channels - tetrameric - ions pass bilayer by following low energy pathways down center of complex - short, narrow segment called selectivity filter provides replacement O2s for lost waters of hydration - water filled central cavity rehydrates ions in middle of passage to allow for ion rehydration

Question 27

Cys-Loops Receptors

Answer 27

- Broadly selective cation or anion channels - pentameric - large water filled pathway runs down center of complex - Fixed rings of charge line central channel and select for charge of permeating ions

Question 28

Multiple binding sites within the P(ore)-Loop channel help increase _____ and _____

Answer 28

permeation and selectivity - single ion bound in pore is too stable to permeate at high rate, but binding of a 2nd destabilizes both, increase rate of mvt

Question 29

Name some examples of Cys-Loops receptors and the type of ion they select for (cation or anion).

Answer 29

- GABA-A receptors - anions - Nicotinic ACh receptors - cations (Ca2+ to excite muscles) - Glycine receptors - anions - 5-HT Type 3 receptors - cations

Question 30

In cys-loop receptors, negative charge rings select for ____ using ____ residues, while positive charge rings select for _____ using ____ residues.

Answer 30

cations, acidic residues anions, basic residues

Question 31

In cys-loops receptors, ____ channels can partially select between divalent and monovalent ions.

Answer 31

cationic

Question 32

Aqueous pore cannot select between monovalent cations, therefore reversal potentials tend to be near ____mV

Answer 32

0 mV

Question 33

Gating

Answer 33

Ability of channels to pass ions across membrane - tightly regulated

Question 34

Selective permeability

Answer 34

Proteins in cell membrane called channels selectively let ions pass lipid bilayer

Question 35

Mvt of ions across lipid bilayer produces ____ ____

Answer 35

electrical signals

Question 36

In terms of current, negative currents are + ions moving ____the cell across the lipid bilayer. While positive currents are + ions moving ____ the cell.

Answer 36

into out of

Question 37

For each cycle, how much net charge does Na/K ATPase pump out of the cell?

Answer 37

+1 charge

Question 38

Nernst potential

Answer 38

Membrane potential that balances an ion's concentration gradient

Question 39

In Ohm's Law, what determines the current that flows for any given conductance?

Answer 39

Driving Force = (Vm - Ex)

Question 40

What is the slope of the line that relates current flow to driving force?

Answer 40

Conductance, G

Question 41

What is a reciprocal of conductance and a measurement of how difficult flow is along a given pathway?

Answer 41

Resistance

Question 42

What is the system attractor and equilibrium point?

Answer 42

Ek (potential of potassium)

Question 43

At rest, what channels have the highest conductance?

Answer 43

Potassium channels

Question 44

A single ion channel is SIGNIFICANTLY faster/slower than the Na/K ATPase channel?

Answer 44

FASTER (7,000,000 ions per second for ion channel compared to 3000+ ions/min for ATPase)

Question 45

Although it looks like the Nernst eqn, the GHK eqn calculates ______ potential, not equilibrium potential.

Answer 45

Steady state