Renal Phys Body Fluid Compartments

Question 1

What is the basic water composition of the body?

Answer 1

60-40-20 rule

60% of body weight = water

40% of body weight = ICF water = 2/3 of total water

20% of body weight = ECF water = 1/3 of total water

Question 2

What are the two parts of ECF?

Answer 2

interstitial fluid = 3/4 of ECF

Plasma = 1/4 of ECF

Question 3

What is the only fluid that can be directly acted on to control its volume and composition?

Answer 3

plasma

Question 4

What is third spacing?

Answer 4

too much fluid shifts from blood vessels into nonfunctional area of cells = trapped btw tissues and organs = edema

Question 5

What are the major ions of the extracellular fluid?

Answer 5

Na+

Cl-

HCO3-

Question 6

Which type of ECF contains more protein anions?

Answer 6

plasma

Question 7

What are the major ions of the ICF?

Answer 7

K+

Po4^3-

Protein anions

Question 8

What are nonelectrolytes?

Answer 8

molecules that contain covalent bonds that prevent them from dissociating in sol’n

Question 9

What is osmolarity vs. osmolality?

Answer 9

osmolarity = # of particles per L sol’n

osmolaLity = # of particles per Kg sol’n

Question 10

How much of the blood is plasma? How much is RBCs?

Answer 10

plasma = 60%

RBCs = 40%

Question 11

How would a loss of ECF affect total plasma protein? What about a gain?

Answer 11

loss of ECF –> gain of total plasma protein (concentration)

gain of ECF –> loss of total plasma protein

Question 12

What is normal hematocrit for a male?

For a female?

Answer 12

0. 4
1. 36

Question 13

How will changes in ECF volume affect hematocrit?

Answer 13

ECF volume loss –> increased hematocrit

ECF volume gain –> decreased hematocrit

Question 14

How would ICF volume changes affect hematocrit?

Answer 14

ICF increase –> increased hematocrit (cells swell)

ICF decrease –> cells shrink –> decreased hematocrit

Question 15

What marker is used to measure the volume of ECF?

Answer 15

inulin

Question 16

What indicator is used to measure plasma volume?

Answer 16

albumin

Question 17

What is the Gibbs-Donnan Effect?

Answer 17

presence of negatively charged proteins in cell that are impermeable to membrane –> causes both water and charges to want to come into cell

= both osmotic and electrochemical gradients generated

Question 18

How does the body counteract the gibbs’donnan effect?

Answer 18

Na/K ATPase counteracts inward force –> pumps 3 Na out for every 2 K in

(PumpKin)

prevents excessive inward mvnt of water

Question 19

What pressure relationships favor filtration?

Answer 19

Capillary hydrostatic pressure > capillary osmotic pressure

Question 20

What pressure relationship favors absorption?

Answer 20

when capillary blood pressure/hydrostatic pressure falls below capillary osmotic pressure

Question 21

When does edema become apparent?

Answer 21

when interstitial volume is increased by 2.5-3 L

need renal retention to actually see edema

Question 22

What is pitting vs non-pitting edema due to?

Answer 22

non-pitting edema = swollen cells due to increased ICF

pitting edema = increased ECF

Question 23

What is the starling eqn for net filtration?

Answer 23

K[(Pc - Pi) - (πc - πi)]

Question 24

What is a hypertonic solution?

Answer 24

causes cells to shrink

NaCl concetration greater than 0.85%

Question 25

What is a hypotonic solution?

Answer 25

causes cells to swell NaCl concentration less than 0.85%

Question 26

What is an isotonic solution?

Answer 26

NaCl concetration equal to 0.85% or 300 mOsm cells stay happy

Question 27

What is a crystalloid replacement?

Answer 27

contain organic or inorganic salts (saline) do not cross plama membranes, but can go across capillary walls = stay in IF and blood

Question 28

What is colloid replacement?

Answer 28

contains large molecules that don't pass through capillary walls = stay in intravascular space and pull in more water to bloodstream

Question 29

What is the eqn for plasm/serum osmolarity?

Answer 29

2(Na) + glucose/18 + BUN/2.8

Question 30

What is the eqn for plasma osmolality?

Answer 30

2(plasma [Na+])

Question 31

What is hypotonic/ hyponatremic dehydration?

Answer 31

Na leaves faster than H20 --\> [Na] in ICF becomes greater than in ECF --\> water will shift from ECF to cells

Question 32

What is hypertonic/ hypernatremic dehydration?

Answer 32

H2O leaves faster than sodium --\> [Na] is greater in ECF --\> water leaves cells serum osmolality and sodium levels will be increased

Question 33

What is a volume contraction?

Answer 33

decrease in ECF --\> decreased blood volume and BP

Question 34

What is volume expansion?

Answer 34

increased ECF --\> increased BP and edema

Question 35

What is a darrow-yannet diagram?

Answer 35

used to study the effect of clinical conditions osmolality = Y axis volume = x axis solid line = normal values dashed lines = change in volume and osmolality

Question 36

What is an iso-osmotic volume contraction? What does it look like on darrow-yannet?

Answer 36

direct loss of ECF --\> only see ECF volume loss, but no change in osmolality or ICF volume

Question 37

What is a hyperosmotic volume contraction? What does it look like on darrow-yannet?

Answer 37

decrease in ECF and ICF volumes increase in body osmolality

Question 38

What does a hypo-osmotic volume expansion look like?

Answer 38

gain of hypotonic fluid --\> increased ECF and ICF, but decreased body osmolality

Question 39

What does an isoosmotic volume expansion look like?

Answer 39

gain isotonic solution --\> increased ECF no change in ICF or osmolality