Electrical Signaling Flashcards Preview

Term IV: Neuro > Electrical Signaling > Flashcards

Flashcards in Electrical Signaling Deck (45):
1

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

Neurons

2

Cells specialized to detect specific environmental cues

Sensory cells

3

Cells that monitor, support and maintain Nervous system function

Glia

4

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

Effector cells

5

Two components of a neuron.

Somatodendritic and axonal

6

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

Dendritic spines -

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

7

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

Dendrite Shafts

8

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

Soma

9

initiates signaling down the Axon

Axon Hillock

10

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

Axon

11

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

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

12

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

charge

13

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

electrical potential

14

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

Earth's electrical potential (aka ground)

15

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

Membrane potential (volts)

16

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

Electric fields

17

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

coming together

18

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

-100 mV and +100 mV

19

Standard convention for membrane potential is

(inside potential - outside potential)

20

What are the two membrane potential determinants?

Charge displacement and membrane thickness

21

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

larger

22

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

Action Potentials

23

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

channel proteins

24

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

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

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.

waters of hydration

26

P(ore)-Loops channels

- 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

27

Cys-Loops Receptors

- 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

28

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

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

29

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

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

30

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

cations, acidic residues

anions, basic residues

31

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

cationic

32

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

0 mV

33

Gating

Ability of channels to pass ions across membrane - tightly regulated

34

Selective permeability

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

35

Mvt of ions across lipid bilayer produces ____ ____

electrical signals

36

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

into

out of

37

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

+1 charge

38

Nernst potential

Membrane potential that balances an ion's concentration gradient

39

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

Driving Force = (Vm - Ex)

40

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

Conductance, G

41

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

Resistance

42

What is the system attractor and equilibrium point?

Ek (potential of potassium)

43

At rest, what channels have the highest conductance?

Potassium channels

44

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

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

45

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

Steady state