Lecture 2 - Osmosis & Surface Tension

Question 1

Define osmosis

Answer 1

process by which water moves across a semi-permeable membrane due to a concentration gradient

Question 2

what category of molecule will not diffuse across a membrane via simple diffusion?

a. small molecules
b. polar molecules
c. charged molecules

Answer 2

c. charged molecules

Question 3

what will not cross the plasma membrane? select all that apply

a. nonpolar molecules
b. large polar molecules
c. small polar molecules
d. ions

Answer 3

d & d

Question 4

T/F: water moves TOWARD the more concentrated solution

Answer 4

TRUE

Question 5

what is osmotic pressure

Answer 5

pressure caused by differences in solutes between solutions separated by a semipermeable membrane; what is needed to stop osmosis

Question 6

what is oncotic pressure

Answer 6

pressure generated by colloids (molecules that do not cross the blood vessel)

Question 7

what is the primary intravascular oncotic molecule

Answer 7

albumin

Question 8

T/F: osmotically active molecules freely cross the semipermeable membrane

Answer 8

FALSE

Question 9

T/F: a non-effective osmole does not generate water movement as it is not freely permeable

Answer 9

TRUE

Question 10

____ is an effective osmole, while ____ is a non-effective osmole

Answer 10

glucose; urea

Question 11

While an effective osmole cannot cross a membrane, it stimulates osmotic water movement by

Answer 11

pulling water to it

Question 12

what is the main intracellular cation?

Answer 12

potassium (K+)

Question 13

What is the main extracellular cation and anion

Answer 13

sodium (Na+); Chloride (Cl-)

Question 14

osmolality

Answer 14

number of osmoles per kg of solvent

Question 15

osmolarity

Answer 15

number of osmoles per liter of solvent

Question 16

what is the osmolarity of plasma

Answer 16

~300 mOsm/L

Question 17

what is the osmole gap and what is its clinical significance

Answer 17

the gap occurs when calculated osmolality does not equal the measured osmolality

*present in uncontrolled diabetes or antifreeze poisoning

Question 18

if a cell is placed into a hypotonic solution what happens

Answer 18

the cell swells (lysis)

Question 19

if a cell is placed into a hypertonic solution what happens

Answer 19

the cell shrivels (crenation)

Question 20

if a cell is placed into an isotonic solution what happens

Answer 20

nothing

Question 21

Which of the following solutions is hypotonic compared with blood?

a. LRS (300 mOsm/L)
b. 3% saline (1023 mOsm/L)
c. 0.45% saline (154 mOsm/L)

Answer 21

c. 0.45% saline (154 mOsm/L)

Question 22

increased surface tension promotes what

Answer 22

alveolar collapse

Question 23

T/F: the bigger the radius, the lower the pressure

Answer 23

TRUE

Question 24

what is surfactant

Answer 24

secretion of type II alveolar cells that decreases surface tension

Question 25

when is surfactant produced? why is this an issue?

Answer 25

near parturition; when birth occurs prematurely, the neonate may suffer respiratory distress

Question 26

T/F: surfactant helps alveolar collapse

Answer 26

FALSE