DSA: Osmosis

Question 1

What is a SOLVENT?

Answer 1

Fluid that serves as the “base” for the solution

*In human body, the solvent is water

Question 2

What is a SOLUTE?

Answer 2

Substance that is dissolved to make the solution

*In human body, solutes include the ions, proteins, steroids, etc…

Question 3

Osmosis produces a significant change in the __________ of the two solutions; the more concentrated solution will _______ in volume as the solvent moves from the less concentrated solution to balance the two solutions

Answer 3

VOLUME, INCREASE

Question 4

Describe DIFFUSION

Answer 4

• Movement of the solute across a membrane when there is a concentration gradient
• Moves from high concentration to low concentration

Question 5

Describe OSMOSIS

Answer 5

• Movement of the SOLVENT

- Result in pressure gradient

Question 6

In the body: the solvent is:

Answer 6

Water

Question 7

In the body: solutes are:

Answer 7

ions, proteins

Question 8

*Despite the different ion concentrations in the intra- versus extracellular fluid, the osmolarity of the two is _________

Answer 8

the same

Question 9

*Osmosis ___________ the concentration of solutes

Answer 9

doesn’t depend on

Question 10

*Osmosis only occurs if

Answer 10

There is a gradient for the water

Question 11

Which ion(s) are in higher concentration in the ECF?

Answer 11

• Sodium
• Chloride
• Calcium
• Bicarbonate

Question 12

Which ion(s) are in higher concentration in the ICF?

Answer 12

Potassium

Question 13

The osmolarity of the ICF and ECF are:

Answer 13

THE SAME, no gradient for osmosis to occur

Question 14

What does OSMOLARITY measure?

Answer 14

Number of osmotically active particles (solute) in the solution

Question 15

Osmolarity is measured in units of ________

Answer 15

osmoles

Question 16

In the body, osmolarity is measured in ________

Answer 16

milliosmoles (mOsm)

1/1000 of an Osmole

Question 17

How to calculate osmolarity?

Answer 17

Osmolarity= g x [C]

Question 18

Osmolarity calculation:

g=1 if:

Answer 18

the solute doesn’t dissociate

Question 19

Osmolarity calculation:

examples of g=1?

Answer 19

Glucose, urea, proteins

Question 20

Osmolarity calculation:

g>1 if:

Answer 20

the solute dissociates when placed in solution

Question 21

Osmolarity calculation:

examples of g>1?

Answer 21

NaCl

g=2 if the NaCl were to completely dissociate into Na and Cl

The measured g=1.8 because not all the NaCl dissociates

CaCl2

g=3 at a max

Question 22

What is the reflection coefficient?

Answer 22

Measure of the solute’s permeability across the membrane

Ranges b/w 0-1

0=solute is fully permeable across the membrane
1= solute is completely impermeable across the membrane

***Important b/c tells if OSMOSIS WILL OCCUR

Question 23

If the reflection coefficient is 0, osmosis ______ occur

Answer 23

WILL NOT

Question 24

If the reflection coefficient is 1, osmosis ______ occur

Answer 24

WILL

Question 25

What is the average osmolarity of the ICF and ECF of the human body?

Answer 25

290 mOsm

Question 26

What is the normal range for osmolarity in the human body?

Answer 26

270-300 mOsm

Question 27

A 0.9% solution of sodium chloride is ________ to RBCs

Answer 27

Isosmotic

*Normal saline

Question 28

What is a CMP?

Answer 28

Complete metabolic profile

Question 29

What is the equation used for estimating osmolality?

Answer 29

=(2x [Na]) + ( [glucose]/18) + ([BUN]/2.8)