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Flashcards in L2 Deck (31):
1

The body of a normal 70 kg adult holds about ......... litres of water

42

2

Hydrophilic substances

glucose, Na+, ethanol and many proteins

3

Hydrophobic substances

fats and waxes and cholesterol.

4

Amphiphilic substances

long chain fatty acids, bile salts and the phospholipids.

5

The rate of diffusion depends on (4):

• The concentration gradient
• The area available for diffusion
• The molecular mass of the solute
• The diffusion coefficient

6

The diffusion coefficient – ...


A physical constant that reflects the molecular
characteristics of both solute and solvent. This constant
also depends on temperature.

7

Osmosis is the ....

Osmosis is the movement of water (or other solvent) through a semipermeable membrane that permits the passage of the water
but not the solute particles.

8

the osmotic pressure -

A hydrostatic pressure sufficient to stop osmosis. Plays an important role in the transport of molecules across membranes.

9

Osmotic pressure equation:

Osmotic pressure (π) = MRT M - Molality, R - universal gas constant (0.31JK-1mol-1), T - the absolute temperature (310K at normal
body temperature)

10

Przypomnienie Osmotic pressure (2)!

Osmotic pressure depends on the number of solute particles present per unit volume of solvent and NOT on their chemical
makeup.
• Salts separate into their constituent ions, so the osmotic pressure that a salt such as sodium chloride will exert will be twice its
molar concentration.

11

.... is the basis of process to purify water called ....

Osmotic pressure, reverse osmosis

12

osmolarity

moles solute particles per litre of a solution. Similarly a 1M solution of glucose has a concentration of 1 Osm (1 Osmol L-1).

13

osmolality

moles solute particles per kg of water. In clinical medicine, osmotic pressures of body fluids are generally expressed as osmolality. One gram mole of a non-dissociating substance in 1kg of water exerts an osmotic pressure of 1 Osmol kg-1.

14

The blood plasma has an osmolality of around ....

300 mOsmol kg-1

15

• The principal ions of the blood plasma (4):
They contribute most of this

(Na+, K+, Cl-, HCO3 -)
(around 290 mOsmol kg-1).

16

przypomnienie dlaczego proteins exert small osmotic pressure

Why do proteins exert such a small osmotic pressure?
Each kg of plasma contains ~ 6.76 g of NaCl and 47.4g of albumin
• Osmotic pressure due to NaCl:
2 * (6.76/58.4) = 0.231 Osmol kg-1 or 231 mOsmol kg-1
• Osmotic pressure due to albumin:
47.4/69,000 = 0.687 mOsmol kg-1

17

przypomnienie

Fluids which are isotonic are also iso-osmotic.
• However, not all iso-osmotic solutions are isotonic with cells.
– iso-osmotic solutions of urea cause cells to swell… why?

18

ile wody w:
1) Intracellular water
2) Extracellular water:
a) Interstitial water
b) Plasma
c) Transcellular water

1) 28L
2a) 10.4L
2b) 2.8L
2c) 0.8L

19

Transcellular water -

The extracellular water in spaces such as the brain ventricles, peritoneal cavity, joint capsules and eyes

20

Interstitial water -

The extracellular water that
lies outside the blood
vessels and bathes the cells

21

Plasma -

The extracellular water
of the blood

22

Intracellular water -

The water within cells

23

przypomnienie woda

Total body water = extracellular water + intracellular water

Extracellular water = plasma + interstitial water

24

przypomnienie zadanie woda

If total body water is 43L, the plasma volume is 3L and the extracellular water volume is 16 litres…

Intracellular water volume = 43 - 16 = 27 L

Interstitial water volume = 16 - 3 = 13 L

25

wzór na koncentrację

concentration = mass/volume

26

przypomnienie Total body water

Total body water can be measured using 3H2O or 2H2O

27

przypomnienie Plasma volume

Plasma volume can be measured using the dye Evans Blue (high affinity for serum albumin).

28

przypomnienie Extracellular volume

Extracellular volume can be measured using a plant
polysaccharide called inulin (NOT insulin).

29

Measuring plasma volume:

• 10 ml of a 1% solution (0.1 g or 100 mg) of Evans Blue was injected into a subject

30

przypomnienie summary

• Cells swell (or burst) when placed in distilled water and shrink when
placed in concentrated salt solutions.

31

Przypomnienie roztwór izotoniczny

Cells placed in a solution of 0.9% sodium chloride in water (i.e. 0.9 g sodium chloride in
100 ml of water) neither swell nor shrink. This concentration has an osmolality ≈ 290 mosmol kg-1
and is said to be isotonic with the cells.