Body Fluids

Question 1

% of lean body mass

% of adipose

Answer 1

LBM = 80%

Adipose = 20%

Question 2

Lean body mass

Answer 2

Contains the body’s water

73% water

Divided into extracellular and intracellular compartments

Question 3

Essential fat

Answer 3

Necessary to sustain life

5% of BW in males (12% in females)

Question 4

Storage fat

Answer 4

Stored subcutaneously between skin and muscles

= 1/2 of the fat in young adults

Other 1/2 = is internalized = visceral fat = more associated with cardio disease

Question 5

Obesity

Answer 5

Defined as an excess body fat expressed as a percent of BW

Males > 25%

Females > 32%

Hypertrophic = increase fat per cell

Hyperplastic = increased number of cells

Question 6

Total body water / 0.73 =

Answer 6

Lean body mass

Question 7

Fat =

Answer 7

Total weight - LBM

Question 8

Water = % of BW

Answer 8

57%

Question 9

% body water varies (?) to body fat content

Answer 9

Inversely

Question 10

During protein folding, water…

Answer 10

Rearranges to accommodate changing exposure of hydrophilic and hydrophobic regions to the water molecules

Question 11

Intracellular volume

Answer 11

25L

63% of body water

= collective volume of fluid in all cells…

Cells regulate by controlling transport processes and regulating effective solute content within cell

Question 12

Extracellular volume

Answer 12

15L

37% of body water

Fluid throughout compartment in dynamic equilibrium ‘internal evironment’

Distributed mostly in interstitial space (11.5L)

Remained in vascular compartment (3.5L)

Must be precisely regulated both in terms of composition, totaly solute concentration (osmolality) and volume

Question 13

Major solutes in EC fluid

Answer 13

Na+, Cl-, HCO3-

Question 14

Major cation in IC fluid

Answer 14

K+

Question 15

Anions in IC fluid

Answer 15

Very little Cl- and HCO3-

Most of anionic cahrges are contirbutes by IC proteins and organic anions

Question 16

Plasma (mMol/L) vs Cell water (mMol/kg H20)

Na+
K+
Cl-
HCO3-
Osmolality

Answer 16

Na+ 135-145. 10-14

K+. 3.6-5.2. 120-145

Cl- 96-107. ~5-10

HCO3- 22-28. <10

Osmolality. 290. 290
(mOsmol/kg)

Question 17

Osmolality

Answer 17

Collective concentration of all solutes in solution

Regardless of size and charge…all have same contribution to the osmolality

Question 18

Anion gap

Answer 18

Difference between the sum of the 2 major cations (Na+ and K+) and the two major anions (Cl- and HCO3-)

Anion gap increases with….increase in organic anions (ketones, acetacetic acid, etc)

—> diabetes mellitus or anaerobic metabolism

Question 19

Hyponatremia

Answer 19

Low plasma Na+

Mild = 130-134 mM/L

Chronic <129

—> can lead to gout and attention and greater incidence of falls

When occurs rapidly…cerebral edema and death if untreated

Because EC fluid osmolality decreases driving water into cells and increasing cell volume —> brain cell edema

Question 20

Aquaporins

Answer 20

Water channels that allow water to diffuse across semi permeable membranes

Question 21

Hypertonic solution

Answer 21

Cell shrinks

Water moves out of cell (where there is less water)

May be associated with dehydration

Obtundation, myoclonus seizures, coma

Hypernatremic encephalopathy

Intracranial hemorrhage

Neuro manifestation occur with sudden changes usually iatrogenic

Question 22

Hypotonic solution

Answer 22

Cell swells

Water moves into cell (where there is less water)

Increase intracranial pressure

Confusion, seizures, coma, myoclonus

Hypo-osmolar encephalopathy

Important to know if condition is chronic or acute

Question 23

Steps to calculate changes with infusions of solutions

Answer 23

1. Add volume to body column
2. Add total mOsmole to body and ECF column
3. Calculate equilibrium concentration by dividing new total solute by new volume
4. Equilibrium concentration applies to both compartments
5. Calculate new volumes of compartments by dividing new total solute by new equilibrium concentration

Question 24

Indicator substance for measuring total body volume

Answer 24

D20

HTO

Question 25

Indicator for measuring extracellular volume (ECV)

Answer 25

Inulin

Mannitol

Radio labeled Na+

Radio labeled sulfate

Question 26

Indicator for measuring blood volume

Answer 26

Radio labeled iron

Cr^51

Question 27

Indicator for measuring plasma volume

Answer 27

RISA (radioiodinated serum albumin)

T-1824 (evan’s blue)

Question 28

Unknown volume =

Answer 28

Amount of indicator / concentration of indicator

Question 29

Blood volume =

Answer 29

Plasma volume / (1-hematocrit)

Question 30

Intracellular volume =

Answer 30

total body water - ECV

Question 31

Interstitial volume =

Answer 31

ECV - PV

Question 32

Changes in ECV and ICV with infusion of a hypertonic solution

Answer 32

ECV = Will expand more than the volume infused

ICV = will get smaller

Question 33

Changes in ECV and ICV with infusion of a isotonic solution

Answer 33

ECV = expands by the SAME amount as volume infused

ICV = no change

Question 34

ECV and ICV with infusion of a hypotonic solution

Answer 34

ECV = expands less than the volume infused

ICV = expands

Question 35

Common theme of change with ECV with infusion of a solution

Answer 35

It will expand…by how much depends on the nature of the solution (hyper, hypo, or iso-)

Question 36

Glucose solutions

Answer 36

Transiently effective osmotically

But are equivalent to water infusions once glucose is metabolized

Question 37

Urea solutions

Answer 37

No osmotically effective because most cell membranes are permeable to urea