Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Phys 801 > Autonomic Nervous System > Flashcards

Autonomic Nervous System Flashcards

1
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What generates membrane potentials?

A

Ion diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What equation is used to calculate the diffusion potential for a single monovalent ion?

A

Nernst equation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What states of voltage-gated sodium channels are involved in generating an action potential?

A

Open, closed, and inactivated states

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do potassium channels affect the action potential waveform?

A

They modify the action potential waveform

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define threshold as it applies to action potentials.

A

The level of depolarization required to trigger an action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the absolute refractory period?

A

The period during which a second action potential cannot be initiated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the relative refractory period?

A

The period during which a second action potential can be initiated only with a stronger stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does ‘all-or-none’ mean in the context of action potentials?

A

Action potentials occur fully or not at all, once the threshold is reached

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do action potentials propagate down an axon?

A

By local depolarization and the opening of voltage-gated ion channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the relationship between axonal diameter and action potential velocity?

A

Larger axonal diameters result in faster action potential velocities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does myelination affect action potential velocity?

A

Myelination increases action potential velocity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the definition of current (I) in biological systems?

A

Flux/unit time or flow of electrical charge, typically associated with ion movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define voltage or potential (V).

A

Strength of an electrical field measured across a membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is resistance (R) in electrical terms?

A

Resistance to current flow, defined by Ohm’s Law: V=IR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is conductance (g)?

A

The ease of current flow, reciprocal of resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is capacitance (C)?

A

The capacity of a material to store charges of opposite sign

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What role does the lipid bilayer play in membrane potential?

A

Acts as a capacitor that stores charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are integral membrane proteins?

A

Proteins that include channels and transporters across the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the result of K+ diffusion across a membrane?

A

Creation of a diffusion potential due to charge separation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does the Nernst equation calculate?

A

The diffusion potential for ions based on their concentration gradients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What maintains concentration gradients of Na+ and K+ in cells?

A

Na+/K+-ATPase

23
Q

What is the function of the Na+/K+-ATPase?

A

Extrudes 3 Na+ ions and transports 2 K+ ions into the cell using ATP

24
Q

What is the typical membrane potential of most neurons?

A

Approximately -70 mV

25
What is the Goldman-Hodgkin-Katz Equation used for?
Calculating membrane potentials arising from multiple ions
26
What is the effect of permeability to K+ or Na+ on membrane potential?
It sets effective limits on physiologically attainable membrane potentials
27
What happens to membrane potential when Na+ channels open?
Membrane potential becomes less negative (depolarization)
28
What is the primary intracellular anion?
Phosphate and proteins
29
What is the primary extracellular anion?
Chloride (Cl-) and bicarbonate (HCO3-)
30
What does the term 'depolarization' mean?
Membrane potential is less negative than resting membrane potential
31
What is the resting membrane potential primarily determined by?
The differential distribution of ions maintained by the Na/K pump ## Footnote Key ions include K+, Na+, and proteins (A-)
32
Define depolarization in the context of membrane potential.
Membrane potential is less negative than resting membrane potential ## Footnote This means the membrane potential becomes more positive.
33
What is an action potential?
A rapid depolarizing change in the membrane potential ## Footnote It is the primary signal of the nervous system.
34
What are the two important properties of ion channels?
* Selectivity * Gating ## Footnote Selectivity allows certain ions to pass more readily, while gating regulates ion diffusion.
35
What opens ligand-gated ion channels?
Binding of intracellular ligands or neurotransmitters ## Footnote Examples include cyclic nucleotides and calcium.
36
What characteristic is exhibited by voltage-gated Na+ channels?
Inactivation ## Footnote Inactivation is a special closed state which the channel enters after being opened.
37
What does the term 'threshold' refer to in action potentials?
The membrane potential above which depolarization is sufficient to generate an action potential ## Footnote Typically around -65 mV.
38
What is the absolute refractory period?
A period during which a new action potential cannot be generated ## Footnote Occurs after an action potential while the membrane is repolarizing.
39
How do K+ channels contribute to the action potential?
They open in response to depolarization, shaping action potential waveforms and contributing to the refractory period ## Footnote K+ channels help to establish the resting membrane potential.
40
What is the role of myelin in action potential conduction?
Increases conduction velocity by lowering cell membrane capacitance ## Footnote Myelin allows charge to spread further down the axon.
41
What is saltatory conduction?
Action potentials skip from one node of Ranvier to the next ## Footnote This occurs due to high density of Na+ channels at the nodes.
42
What is the length constant (l)?
The distance over which the voltage decays by 63% ## Footnote It characterizes how far charge spreads down the membrane.
43
What happens if inactivation of Na+ channels is slowed?
Broadened action potential ## Footnote Slow sodium channel inactivation can contribute to conditions like epilepsy.
44
True or False: Action potentials can move backwards along an axon.
False ## Footnote Upstream tissue is refractory, preventing backward propagation.
45
What is the significance of the sodium channel blockers?
Used pharmacologically for local anesthesia and anti-arrhythmic purposes ## Footnote Examples include lidocaine and flecainide.
46
Fill in the blank: The _______ is the resistance to charge spreading through the interior of the cell.
Rin ## Footnote Lower Rin allows charge to spread further down the axon.
47
What is the typical conduction velocity of large myelinated fibers?
Can exceed 100 m/s ## Footnote This is significantly faster than unmyelinated fibers.
48
What is the role of the Na/K pump in maintaining resting membrane potential?
Maintains the differential distribution of ions ## Footnote This is crucial for the generation of action potentials.
49
What is hyperpolarization?
Membrane potential is more negative than resting membrane potential ## Footnote This often occurs after the action potential.
50
What is the function of the 'ball and chain' mechanism in K+ channel inactivation?
Plugs the pore of the channel ## Footnote This mechanism aids in the rapid closing of K+ channels.
51
What is electrotonus in terms of action potential propagation?
Passive spread of charge through a nerve cell ## Footnote This helps in the movement of action potentials along the axon.
52
What determines nerve conduction velocity?
Distance of electrotonic charge spread ## Footnote Greater distances allow for faster action potential propagation.
53
What is the effect of demyelinating diseases on action potentials?
Slows action potential velocity and may block propagation ## Footnote Multiple sclerosis is an example of such a disease.

Phys 801 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions