Lecture 9

Question 1

Semipermeable membrane?

Answer 1

A material containing a network of microscopic holes or pores that permits the flow of small solvent molecules but restricts the flow of larger solute molecules

Question 2

Solute

Answer 2

The substance being dissolved

Question 3

Solvent

Answer 3

The substance doing the dissolving

Question 4

Osmosis?

Answer 4

The flow of solvent molecules through a semi-permeable membrane from a region of lower solute concentration to a region of higher solute concentration

Question 5

Osmotic pressure?

Answer 5

The pressure needed to prevent osmosis from happening

Question 6

Main difference between molarity and osmolarity?

Answer 6

Osmolarity takes into account osmotic pressure, whereas molarity doesn’t

Question 7

Solutions containing different particles, but have the same osmolarity have the same osmotic pressure?

Answer 7

Yes

Question 8

What is a dilute solution?

Answer 8

When each cation and anion is completely surrounded by H2O molecules (hydration)

Question 9

Why are dilute solutions very important in the body?

Answer 9

Bc we have a lot of electrolytes (cations and anions) in our body. We also have a lot of water in our bodies. So if we didn’t have all of this water, then the electrolytes would come together (+ and -) and precipitate out, clogging up our blood vessels

Question 10

What is a concentrated solution?

Answer 10

• When each cation and anion have incomplete hydration and therefore tend to form ion pairs
• Not enough water molecules surrounding the ion
• Reduced osmolarity

Question 11

When using the Van’t Hoff Factor, why are there slightly different values for i than expected?

Answer 11

The values of i are slightly lower than expected bc of ion pairing

Question 12

Osmolarity equation?

Answer 12

Osmolarity = i x M

Question 13

What is a good indication of kidney function?

Answer 13

A comparison of the osmolarity of blood and urine

Question 14

Hypertonic?

Answer 14

• The surrounding solution has a higher solute concentration, than the solution inside the red blood cells
• Causes rbc’s to shrink (crenation)

Question 15

Isotonic?

Answer 15

The surrounding solution has the same osmolarity, same concentration, as the solution inside the red blood cells

Question 16

Hypotonic?

Answer 16

• The surrounding solution has a lower solute concentration, than the solution inside the red blood cells
• Causes rbc’s to burst (lyse) (Haemolysis)

Question 17

What are all intravenous preparations made with?

Answer 17

Isotonic solutions

Question 18

Why use IV fluids?

Answer 18

• Patients who can’t swallow safely
• Patients who can’t drink enough to keep up with their loss of fluids
• Patients who require medication that is destroyed by gastric juices
• Patients who must rapidly increase medication or electrolyte concentration in blood

Question 19

What are the two main lines of communication within the body?

Answer 19

• The circulatory system

- The nervous system

Question 20

Which protein contributes 75-80% to the osmotic effect of the blood?

Answer 20

Albumins regulate the osmolarity of blood