Body Fluids Flashcards
Claude Bernard…
- Environment surrounding cell is different from external env.
- Internal environment remains constant under normal conditions
Water content of
Skin
Muscle
Organs
Bone
Fat
Skin: 70%
Muscle: 75%
Organs: 70-80%
Bone: 25%
Fat: 10%
Water content for men and women
Estrogen promotes fat deposition in women = lower water %
Age influence on water content
High as baby, then lowers a lot with age, less than 50% after 60 yrs old
Water Intake
Oral fluid
Oral intake as food
Oxidative water from metabolism
Water Output
Insensible - don’t notice: Lungs, skin
Sensible: kidneys (urine), stool (feces)
Water balance
Intake = obligatory loss + facultative loss
Insensible persperation
- Pure water
- Passive
- Entire skin surface
- Continuous
Sweating
- Electrolyte solution
- Active
- Sweat glands
- Activated by heavy work
Causes of negative water balance
Reduced intake
Excessive loss from gut (diarrhea)
Excessive sweating
Excessive loss in breathing
Excessive loss in urine
Water intoxication (cause and effect)
Due to excessive intake
Causes renal system failure
Body water compartments
- Intracellular fluid (40% water body mass): inside cells
- Extracellular fluid (20% water body mass): around cells
a) Major: Interstitial fluid (15%), Plasma (5%)
b) Minor: Lymph (~1-2% ECF), Transcellular fluid (<1-
2% of ECF)
Plasma
Where blood cells are suspended
Hematocrit
% of blood occupied by red blood cells
Height of erythrocyte column / height of total blood column
Interstitial fluid
Fluid surrounding all individual cells
Lymph / Lymphatic system
Network of blind ended tubules
Lymph / Lymphatic system
Network of blind ended tubules
Drains into large veins in chest
Transcellular Fluid
Secreted by cells into body cavities lined by epithelium
Body Fluids
Water: 60%
- ICF: 40%
- ECF: 20%
- ISF: 15%
- Plasma: 5%
Indicator Dilution Method requirements
- Quantity of test substance introduced
- Concentration of the substance
Indicator equation
V = Q/c
V: volume
Q: quantity
c: concentration
Indicator Procedure
- Inject quantity into vein
- Allow time to equilibrate
- Remove known volume of blood, and centrifuge to obtain plasma
- Measure concentration in unit of plasma
- Calculate V = Q/c
Indicator choice
Non-toxic
Diffuse through all compartments (capillary wall and cell membrane)
Does not induce changes in water distribution between compartments (diffusion or osmosis)
Easy to measure its concentration
Examples of indicators
Antipyrine
D2O
T2O
