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PHYSIO LEC > Module 1.3 > Flashcards

Module 1.3 Flashcards

1
Q

cell membrane helps cells maintain ___________ -
stable internal balance

A

homeostasis

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2
Q

the cell membrane maintains homeostasis through balancing the ________ (4) through active and passive transport

A

pH, temperature, glucose (sugar intake), water balance

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3
Q

if a solution’s pH is unbalanced, it is corrected with a

A

BUFFER

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4
Q

direction of diffusion

A

high to low

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5
Q

direction of osmosis

A

high water to low water
low solute to high solute

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6
Q

When a cell is placed in a hypertonic solution, the water diffuses out of the cell, causing the cell to _____.

A

shrivel

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7
Q

When a cell is placed in a hypotonic solution, the water diffuses into the cell, causing the cell to _____ and possibly explode.

A

swell

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8
Q

is a distribution of charge across the cell membrane

A

membrane potential

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9
Q

Membrane potentials

A. The body as a whole is electrically _____

B. All of the cells of body have an _______ across their membrane (_______) known as the membrane potential

C. Membrane potentials develop because of differing _________ between the inside and outside of the cell

A

neutral
electrical potential ; Voltage difference
ion concentrations

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10
Q

The exact value measured for the resting membrane
potential varies between cells, but ______ is a commonly reported value

A

-70 mV

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11
Q

________ is determined by the difference in charge between two points
- membrane potential,
- influence transport

A

Potential difference

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12
Q

Principals of electricity

  1. Units of electrical potential are in ______ or for biological system _______
  2. Voltage is always measured between two points (________)
A

volts (V) ; millivolts (mV) ; 1 V = 1000mV
Potential difference

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13
Q

flow of electrical charges from one point to another

A

current

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14
Q

B. Current

  1. Like charges repel unlike attract
  2. Ions tend to move from areas of greater concentration to areas of least concentration
  3. Movement of a positive ion from one side of a membrane to the other implies a _______ is left behind
A

negative charge

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15
Q

the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperature, remain constant.

A

Ohm’s Law (I = E / R)
R = resistance
I = current flow
E = electrical potential

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16
Q

C. Current Flow

  1. Cell - Aqueous solution + good ________ (Ions and water)
  2. Lipid membrane - A few charged groups can not carry current - high electrical resistance - _________
  3. ECF and ICF - both have _________
A

good conductor (ions)
good insulator (lipid membrane)
low electrical resistance (ECF and ICF)

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17
Q

describes the steady state of the cell

A

Resting Membrane Potential

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18
Q

By convention (Resting MP) - ECF (outside of the cell) is assigned a voltage of

A

zero

19
Q

Polarity of the membrane is stated in terms of the sign of the ________ inside of the cell

A

excess charge inside of the cell

20
Q

Types of channels (2)

A
  1. Leak Channels
  2. Na+/K+ ATPase Pump
21
Q

Open all of the time - slow leak of ions, simplest type of ion channel, in that their permeability is more or less constant (neurons)

A

Leak channels

22
Q

channel that transports sodium, potassium & chlorine

Accounts for 95% of the resting membrane potential

A

Leak channels

23
Q

These channels open and close at random, allowing ions to pass through when they are open.

A

Leak channels

24
Q

_______ :
a. Unequal transport of positive ions makes the ICF more _______ than it would be from diffusion alone
b. ________ pump
c. Accounts for 5% of resting membrane potential

A

Na+K+ATPase Pump;

negative,
Electrogenic

25
Q

Other types of channels (4)

A

a. Resting K+ channel
b. Voltage-gated channel
c. Ligand-gated channel
d. Signal-gated channel

26
Q
  • channel that is always open
  • are responsible for generating the resting potential across the membrane.
A

Resting K+ channel

27
Q
  • channel that opens (transiently) in response to change in the membrane potential
  • are responsible for propagating action potentials along the axonal membrane
A

Voltage-gated channel

28
Q

opens (closes) in response to a specific extracellular neurotransmitter

A

ligand-gated channel

29
Q

opens (closes) in response to a specific intracellular molecule

A

signal-gated channel

30
Q

Two types of ion channels in dendrites and cell bodies are responsible for generating electric signals in postsynaptic cells

A

ligand-gated channel and signal-gated channel

31
Q

What are the complications of high potassium?

A

Hyperkalemia = too much K+ in the blood

32
Q

What are the two forms of ion gradients?

Together these form what is known as the __________

A
  1. Chemical Concentration Gradient
  2. Electrical concentration gradient (Charge buildup and charge differential)

electrochemical gradient

33
Q

Membrane potential: 75% more permeable to ____ (K+/Na+) than ____(K+/Na+) due to leak channel

A

K+ than Na+

34
Q

In all cells a potential difference across the membrane exists
a. Inside is ______ (Na+K+ATPase)
b. Membrane potentials usually within ___ to ___ mv

A

negative because Na+/K+ ATPase;
-40 to -90

35
Q

A cell with a resting membrane potential is
said to be

A

polarized

36
Q

if resting MP, Both the inside and the outside of the cell are

A

electrically neutral

37
Q

Factors that determine the resting membrane potential (4)

A

Selective permeability of the of the plasma membrane
Leak channels
Na+K+ATPase pump
Differences in ion concentrations

38
Q

Many substances are in the cell but the mobile ions _________ (4) play the most important roles

A

Na+, K+, Ca++ and Cl-

39
Q

ECF: ____ helps to balance ____
ICF: _____ balance ____

A

Cl-, Na+
Proteins (Neg charge), K+

40
Q

At rest - Slightly permeable to Na+ 75 times more permeable to ___, and freely permeable to ___

A

K+, Cl-

41
Q

_________ or ______ at which ion movements in both directions across the membrane are exactly balanced (net movement = zero)

A

Equilibrium potential or electrochemical potential

42
Q

At equilibrium point, the ion flux = ____

A

0 (implies no net ion movement)

43
Q

Equilibrium potential or also known as

A

Nernst potential

44
Q

the value of the equilibrium potential (__________) for any ion depends on the concentration gradient across the membrane for that ion

A

Nernst potential

PHYSIO LEC (12 decks)

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