L2

Question 1

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

Answer 1

42

Question 2

Hydrophilic substances

Answer 2

glucose, Na+, ethanol and many proteins

Question 3

Hydrophobic substances

Answer 3

fats and waxes and cholesterol.

Question 4

Amphiphilic substances

Answer 4

long chain fatty acids, bile salts and the phospholipids.

Question 5

The rate of diffusion depends on (4):

Answer 5

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

Question 6

The diffusion coefficient – …

Answer 6

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

Question 7

Osmosis is the ….

Answer 7

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.

Question 8

the osmotic pressure -

Answer 8

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

Question 9

Osmotic pressure equation:

Answer 9

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

Question 10

Przypomnienie Osmotic pressure (2)!

Answer 10

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.

Question 11

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

Answer 11

Osmotic pressure, reverse osmosis

Question 12

osmolarity

Answer 12

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

Question 13

osmolality

Answer 13

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.

Question 14

The blood plasma has an osmolality of around ….

Answer 14

300 mOsmol kg-1

Question 15

• The principal ions of the blood plasma (4):

They contribute most of this

Answer 15

(Na+, K+, Cl-, HCO3 -)

around 290 mOsmol kg-1

Question 16

przypomnienie dlaczego proteins exert small osmotic pressure

Answer 16

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

Question 17

przypomnienie

Answer 17

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?

Question 18

ile wody w:

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

Answer 18

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

Question 19

Transcellular water -

Answer 19

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

Question 20

Interstitial water -

Answer 20

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

Question 21

Plasma -

Answer 21

The extracellular water

of the blood

Question 22

Intracellular water -

Answer 22

The water within cells

Question 23

przypomnienie woda

Answer 23

Total body water = extracellular water + intracellular water

Extracellular water = plasma + interstitial water

Question 24

przypomnienie zadanie woda

Answer 24

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

Question 25

wzór na koncentrację

Answer 25

concentration = mass/volume

Question 26

przypomnienie Total body water

Answer 26

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

Question 27

przypomnienie Plasma volume

Answer 27

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

Question 28

przypomnienie Extracellular volume

Answer 28

Extracellular volume can be measured using a plant

polysaccharide called inulin (NOT insulin).

Question 29

Measuring plasma volume:

Answer 29

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

Question 30

przypomnienie summary

Answer 30

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

Question 31

Przypomnienie roztwór izotoniczny

Answer 31

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.