Renal Phys 1

Question 1

What are the three body fluid compartments?

Answer 1

ICF, ECF, other (transcellular)

Question 2

How much of the total body fluid is ICF?

Answer 2

40% or 2/3

Question 3

How much of the total body fluid is ECF?

Answer 3

20% or 1/3

Question 4

What are the two components of ECF?

Answer 4

plasma and interstitial fluid

Question 5

Does interstitial fluid or the plasma make up more of the ECF?

Answer 5

interstitial fluid

Question 6

Which has a higher concentration of proteins, interstitial fluids or plasma? Why?

Answer 6

plasma, because proteins cannot cross the capillary membrane easily

Question 7

Which component can you use to regulate volume?

Answer 7

the plasma

Question 8

Water added to the body first enters and leaves through which compartment?

Answer 8

ECF

Question 9

What is the Gibbs-Donnan effect?

Answer 9

Since there are more negatively charged proteins in the plasma, cations will enter the plasma due to their attraction to the negative charge and anions will remain in the interstitial fluid. This creates an osmotic and electrochemical gradient across the membrane

Question 10

How do you counteract the Gibbs-Donnan effect?

Answer 10

the Na/K ATPase counteracts this force by pumping 3 sodium out, which will allow water to follow.

Question 11

What is third spacing? What is its clinical relevance?

Answer 11

Third-spacing occurs when too much fluid moves from the intravascular space (blood vessels) into the interstitial or “third” space-the nonfunctional area between cells. This can cause potentially serious problems such as edema, reduced cardiac output, and hypotension.

Question 12

What is the primary ECF cation? Anion?

Answer 12

Na+ ; Cl-

Question 13

What is the primary ICF cation?

Answer 13

K+ ; phosphate

Question 14

Why can electrolytes cause greater fluid shift?

Answer 14

because of their high osmotic power; they can dissociate in water to at least two ions

Question 15

How do osmolality and osmolarity differ?

Answer 15

Osmolality measures osmotically active particles per kg of water, while osmolarity measures the particles per liter of total solution

Question 16

Describe the compartmentalization of fluids in blood

Answer 16

Blood has both ECF (plasma) and ICF (RBC); about 60% of blood is plasma and 40% is RBC

Question 17

What is hematocrit and what are the normal values for men and women?

Answer 17

It is the fraction of the blood that is RBC;
men 0.40
women 0.36

Question 18

How does ECF volume loss change total plasma protein (concentration) and hematocrit?

Answer 18

It increases the concentration and increases hematocrit

Question 19

How does ECF volume gain change total plasma protein (concentration) and hematocrit?

Answer 19

decreased total plasma protein (dilution) and decreased hematocrit

Question 20

What causes fluid to leave the capillary?

Answer 20

Hydrostatic pressure

Question 21

What causes fluid to enter the capillary?

Answer 21

plasma colloid osmotic pressure - pulling force of albumin attracting water into capillary

Question 22

What are the two causes of edema?

Answer 22

1. alteration in capillary hemodynamics (starling forces)

2. inappropriate renal retention of dietary Na+ and water expansion of ECF volume

Question 23

What are the three types of solution tonicity? What are the differences?

Answer 23

Isotonic, hypertonic and hypotonic.
Isotonic environment has a NaCl concentration = .85%
Hypertonic environment has a NaCl concentration > 0.85%
Hypotonic environment has a NaCl concentration < 0.85%

Question 24

what are the two types of replacement therapy?

Answer 24

Colloid and Crystalloid. Colloids are infused and remain in the capillaries and draw fluid into vessels. Crystalloids contain organic or inorganic salts and do not cross plasma membranes (remain in ECF).

Question 25

How do you calculate serum osmolality?

Answer 25

(sodium*2) + (glucose/18) + (BUN/2.8)

Question 26

How can dehydration occur?

Answer 26

decreased water intake, increased fluid loss or both

Question 27

what are the two types of dehydration? Describe them

Answer 27

Hyponatremic dehydration - loss of sodium is greater than the loss of water in the ECF, so water flows into cell (hypotonic)

Hypernatremic dehydration - loss of water is greater than the loss of sodium in the ECF, so water leaves the cell (hypertonic)

Question 28

What do volume contraction and volume expansion refer to? what is its clinical relevance?

Answer 28

a decrease or increase in ECF volume, respectively. volume expansion can cause increased blood pressure and edema

Question 29

How does acute fluid loss (hemorrhage, diarrhea and vomiting) effect a darrow-yannet diagram

Answer 29

causes decrease in ECF volume and no change in body osmolality and ICF volume

Question 30

How does a hypotonic fluid loss condition (dehydration, diabetes, alcoholism) effect a darrow-yannet diagram?

Answer 30

water loss in ECF causes increased concentration of solutes: decrease ECF and ICF volumes but increase in body osmolality

Question 31

How does a gain of isotonic saline (isoosmotic volume expansion) effect a darrow-yannet diagram?

Answer 31

increase in ECF but no change in osmolality and ICF volume

Question 32

How does a gain of hypotonic fluid (excess water drinking or SIADH) effect a darrow yannet diagram?

Answer 32

increase in ECF and ICF volume, but decrease in body osmolality.