Forces Across Membranes 3 Flashcards Preview

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Flashcards in Forces Across Membranes 3 Deck (34)
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1
Q

What is osmosis?

A

Net movement of water from regions of high concentration to regions of low concentrations

2
Q

What is diffusion?

A

Net movement of solute from regions of high concentration to regions of low concentration

3
Q

How does the body maintain osmotic equilbrium?

A

By water moving freely between the ECF and ICF

4
Q

What relationship does the concentration of H2O have to the concentration of solute?

A

Inversely related, the more solute particles the more they displace water

5
Q

What must the concentration and volume of water and solute of a membrane permeable to both be?

A

The same

6
Q

In terms of volume and water, how are they different across a membrane if it is only permeable to water and not the solute?

A

The same concentration of water on either side but a different volume

7
Q

What is osmotic pressure?

A

Pressure that must be applied to stop osmotic movement

8
Q

What is concentration expressed as?

A

mol/L

9
Q

How many molecules are in 1 mol

A

6.02x1023 molecules

10
Q

What does a concentration of 1M mean?

A

Concentration of 1 mol/L

11
Q

What determines the osmotic effect of water (particles or molecules)?

A

The number of particicles, for example:

1 mole of glucose added to 1L of water reduces [H2O] by 1 mole/L

1 mole of NaCl added to 1L of water reduces [H2O] by 2 mole/L

12
Q

What is osmolarity?

A

Measure of concentration of biological solutions in units of Osmoles

13
Q
A
14
Q

What is osmole?

A

Describes the number of particles per L of solution

15
Q

Give examples of the use of Osmole as a unit?

A

1M solution of glucose has an osmolarity of 1osmol/L

1M of NaCl has an osmolarity of 2osmol/L

16
Q

What does normal plasma have an osmolarity of and how does this compare to within cells?

A

285mOsmol/L, which is the same within cells

17
Q

What does osmolarity not describe which is important?

A

The nature of the particles (if they can cross the membrane)

18
Q

What does osmolarity describe?

A

The number of particles in solution

19
Q

What happens to water when the concentration of a solute which cannot pass the membrane changes?

A

Change in concentration creates an osmotic flux which causes a net movemet of water

20
Q

What does a net movement of water cause?

A

A change in volume

21
Q

What is the volume of a cell dependent on?

A

The concentration of non penetrating solutes on either side of the membrane

22
Q

What is osmolarity?

A

Describes the total number of particles in solution

23
Q

What is tonicity?

A

Describes the total number of non penetrating particles in solution

24
Q

What definitions do osmolarity use?

A

Isometric

Hypoosmotic

Hyperosmotic

25
Q

What does isometric mean?

A

Same total number of solute particles as ECF)

26
Q

What does hypoosmotic mean?

A

Fewer total number of solute particles

27
Q

What does hyperosmotic mean?

A

Greater total of solute particles than ECF

28
Q

What definitions does tonicity use?

A

Isotonic

Hypotonic

Hypertonic

29
Q

What does isotonic mean?

A

Same number of non penetrating solute particles as normal ECF

30
Q

What does hypotonic mean?

A

Few number of non penetrating particles than ECF

31
Q

What does hypertonic mean?

A

Greater number of non penetrating solute particles than ECF

32
Q

What happens to cells in a hypotonic solution?

A

Swell as water moves down the chemical gradient into the cell

33
Q

What happens to cells in a hypertonic solution?

A

Shrink as water moves down the chemical gradient out of the cell

34
Q

What is intravascular haemolysis?

A

Cells bursting, which can kill due to introducing proteins in the ECF increasing the tonicity