Body Fluids

Question 1

% of Water in various tissues

Answer 1

-Skin 70%
-Muscle 75%
-Heart,Liver, 70-80%
,Brain Kidney

• Bone 25%
• Fat (adipose) 10%

Question 2

How does water differentiate in proportions of body mass

Answer 2

Normal = 60%
obese/fatter: lower percent = 45%
Skinny = 75%

Amount of water remains constant but percent changes depending on mass

Question 3

Body Water (as % of body mass)
Percents for age and gender:

Answer 3

Infants = 65%
10-18 yrs = 59%m - 57%f
18-40yrs = 61%m - 51%f
40-60yrs = 55%m - 47%f
>60yrs   = 52%m - 46%f

*m= male f= female

Question 4

How to calculate approximate Body Water

Answer 4

For 70 kg male: %water ~60%

Absolute amount of water
(70x60)/100 = 42 kg = ~42L

Question 5

Sources for intake of water

Answer 5

Oral fluid - 1.2L
Oral Intake as food - 1.1L
Oxidative water-
from metabolism 0.4L

Question 6

Sources for Output of water

Answer 6

Lungs - 0.4L )__> Insensible
Skin - 0.5L )

Kidney - 0.5L
Stool (feces) 0.1 L

Question 7

Obligatory Losses

Answer 7

Account for 1.5 L of water

insensible ~1.0L
Urine + Stool ~0.5L

Question 8

Facultative Losses

Answer 8

Vary with intake

-kidney(major homeostatic organ)

Question 9

Insensible perspiration

Answer 9

1. Pure Water
2. Passive Evaporation(affected by ambient temp. and relative humidity)
3. Entire skin surface(present even in individuals lacking sweat glands)
4. Continous

Question 10

Sweating

Answer 10

1. Electrolyte solution
2. Active secretion
3. Sweat glands
4. Activated by heavy work or high temperature

Question 11

Approximate turnover of water in a 24 hr period

Answer 11

3-4% of body weight — adults

~10% of body weight —- infant

Question 12

Compartments of Total body Water

Answer 12

Total body Water =60% of mass

Of this 60% mass
Intracellular Fluid(ICF) = 2/3 or 40% or body mass
Extracellular Fluid(ECF) = 1/3 or 20% of body mass

Of the ECF
5% of body weight is plasma
15% of body weight is ISF

Two subcompartments
Lymph Drainage ~1-2% of ECF
Transcellular

Question 13

Interstitial Fluid

Answer 13

fluid which percolates between individual cells

Question 14

Transcellular fluid

Answer 14

aggregate of small fluid volumes secreted by specific cells into a number of body cavities (line by epithelial cells) and having specialized functions

Question 15

Calculating Total Water Mass + mass of compartments

Answer 15

Equation for find total volume
V= Q/c q=quantity c=conc.

Use Antipyrine, D20, T2O for measuring TOTAL (ICF+ECF)

Use Inulin, sucrose, mannitol to measure TOTAL ECF

Use Evans Blue to measure TOTAL PLASMA volume

Question 16

Body fluids- ionic composition

Answer 16

ICF - high in K+ (and Mg++)
but low in Na+ and Cl-

ECF - High in Na+, Cl- and low in K+