Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A & P Fall 2013 > Membrane Potentials: Chapter 11 > Flashcards

Membrane Potentials: Chapter 11 Flashcards

1
Q

Action Potential

A
  • electrical impulses that are carried along the entire length of axons
  • always the same amplitude regardless of strength of stimulus
  • CNS interpretation and response is impulse frequency based
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Voltage

A

(V) measure of potential energy generated by separate charge (ie battery)

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

Potential difference

A

voltage measured between two points

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

Current

A

(I) the flow of electrical charge between two points

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

Resistance

A

(R) hindrance to charge flow

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

Insulator

A

substance with high electrical resistance

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

Conductor

A

substance with low energy resistance

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

What does the electrical current and the body reflect?

A

Flow of Ions (NOT ELECTRONS)

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

What is needed to have a potential of electrical flow through a membrane?

A
  • the number of ions is different across the membranes

- the membrane provides resistance to ion flow

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

What is the importance of Ion channels?

A

It allows ions to pass through membranes

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

Passive or Leakage Channels

A
  • always OPEN!
  • Ions flow along the concentration gradient for the particular ion
  • When gradient is equal on both sides then it will stop
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Chemically Gated Channels:

A

-open with binding of a specific neurotransmitter or hormone
IE: NA+ -K+ gated channel
-Closed when a neurotransmitter/hormone is not bound to extracellular receptor

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

Voltage Gated Channels:

A
  • open and close in response to a specific membrane potential… (- inside, + outside)
  • IE: NA channel
  • Closed when intracellular environment is negative (NA cannot enter, nor K exit cell)
  • Open when a neurotransmitter is attached to receptor (NA enters, K exits)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Mechanically Gated Channels:

A

open & close in response to physical deformation of receptors (as in sensory receptors for touch & pressure)
-IE: Merkel cells deform in response to touch, opening NA channels

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

What happens when a gated channel is open?

A
  • Ions move quickly across membrane
  • movement along electrochemical gradients
  • electrical currant is created
  • voltage changes across membrane?
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Chemical concentration gradient

A

when ions diffuse passively from an area of higher concentration to an area of lower concentratoin

17
Q

Electrical Gradients

A

ions move toward an ear of opposite electrical charge

18
Q

Electrochemical Gradienat

A

when electrical and concentration gradients taken together

19
Q

Resting Membrane Potentials

A

potential difference across membrane is -70mV

-inside is negative, outside is positive

20
Q

Polarized membrane

A

inside negative, outside positive

21
Q

What are the primary reasons for ionic differences in membranes?

A

-Differential permeability of plasma membrane

higher concentration of sodium on outside

22
Q

Sodium-Potassium Pump

A

pump stabilizes the resting membrane potential by maintaining concentration gradients for sodium and potassium.

  • requires ATP
  • Pumps agains gradient
23
Q

Concentration of potassium:

A

higher on inside of cell

-nerve plasma membrane is very permeable to K+ leaving out

24
Q

Concentration of Sodium:

A

higher on outside of cell

-membrane is only slightly permeable to NA leaking in

25
Q

How is membrane equilibrium reached?

A
  • Sodium potassium pump
  • maintaining concentration gradient
  • maintaining negative resting membrane potenial
26
Q

What type of signals do membrane potentials send when there are changes?

A
  • graded potentials

- action potentials

27
Q

graded potential:

A

short distance incoming signals to dendrites or nerve cell bodies

28
Q

action potential

A

long-distance signals of the axons

29
Q

What causes a change in membrane potential?

A
  • changes in membrane permeability to ions

- alterations of ion concentration across membrane

30
Q

What are the three events that can change the membrane potential?

A
  • Depolarization
  • Repolarization
  • Hyperpolarization
31
Q

Depolarization

A

the inside of membrane becomes less negative relative to the outside

32
Q

Repolarization

A

membrane returns to its resting potential (-70mV)

33
Q

Hyperpolarization

A

inside of membrane becomes more negative than resting potential

A & P Fall 2013 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions