Fluid Strength (ASAN002/5)

Question 1

What is Molar Concentration? (1)

Answer 1

The number of molecules per litre.

Question 2

What is A Mole? (1)

Answer 2

A mole is a stand measure of the number of particles (ions or molecules).

Question 3

What does the actual weight of a mole depend on? (1)

Answer 3

Actual weight of mole depends on the substance

Example:
1 mole of salt weighs 58g
1 mole of lead weighs 207g

Question 4

What is a Millimole?

Answer 4

Millimole = one thousandth of a mole

Question 5

Why do we usually measure fluid concentrations in Millimoles per L? (2)

Answer 5

• Biological fluids are very dilute
• Easier & more convienient to measure than Moles.

Question 6

How do you measure the Concentration of a solution? (1)

Answer 6

The mass of solute that is dissolved in a volume of solvent

Question 7

What are Solutes & Solvents? (1)

Answer 7

Solutes dissolve in a solvent.

Question 8

What is the Solute & Solvent in saline solution? (2)

Answer 8

Sodium chloride (solute)
dissolved in water (solvent)

Question 9

What is Gram% or gram/unit (g/dl)? (1)

Answer 9

Number of grams of solute in 100ml of solvent

Question 10

How much Solute & Solvent would make a 1% solution of saline? (2)

Answer 10

1g solute (sodium chloride)
in 100mls of solvent (water).

Question 11

What is Osmosis? (1)

Answer 11

When water moves from a lower solute solution across a semi–permeable membrane to a higher solute solution.

Question 12

What is a Semi–permeable membrane? (1)

Answer 12

Membrane that allows some particles to pass through but not others.

Question 13

What is a good example of a Semi-permeable membrane? (1)

Answer 13

Cell Membrane

Question 14

What is Osmotic Pressure?

Answer 14

• Measure of the force of osmosis
• How much pressure is needed to prevent osmosis

eg: low solute concentration on one side of semi–permeable membrane and high solute concentration on other creates high osmotic pressure and water to move from lower to higher solute side.

Question 15

What is Tonicity?

Answer 15

An indication of osmotic pressure in relation to cells.

Question 16

What is Tonicity is influenced by? (2)

Answer 16

• Solutes that can’t cross Semi-Permeable Membranes (SPM).
• These are the only solutes that exert osmotic pressure.

Question 17

What solutes do not effect tonicity and why? (2)

Answer 17

• Solutes that freely cross SPM do not effect tonicity.
• These solutes are always equal on both sides.

Question 18

What is an Isotonic solution? (1)

Answer 18

Solution that exerts equal osmotic pressure to body fluid.

Question 19

What is an example of an Isotonic solution? (1)

Answer 19

0.9% saline

Question 20

What is a Hypertonic solution? (1)

Answer 20

Solution that exerts a greater osmotic pressure than body fluid.

Question 21

What is an example of a hypertonic solution? (1)

Answer 21

7% hypertonic saline

Question 22

What is a Hypotonic solution? (1)

Answer 22

Solution that exerts a lower osmotic pressure than body fluid.

Question 23

What is an example of a Hypotonic solution? (1)

Answer 23

0.45% NaCl

Question 24

Answer 24

When fluid that cells are in is ↑ concentration than inside cells, water moves from inside to outside cells, causing cells to shrink & shrivel up (crenate).

When fluid that cells are in is ↓ concentration than inside cells, water moves from outside to inside cells, causing them to swell and sometimes rupture (lyse).