6. ECF constitutes of:
A. Interstitial fluid including
lymph
B. Plasma
C. Transcellular fluids
Transcellular fluids:
CSF
Intraocular fluid
Gastrointestinal secretions
Pleural fluid
Pericardial fluid
Peritoneal fluid
Synovial fluid
Fluid in urinary tract
More the amount of fat, lesser the ECF volume
Elderly – lesser ECF volume
Infants & children – greater ECF volume
7. Body electrolytes
• 7% of total body weight
• Functions of electrolytes in the human body
− Maintenance of acid-base balance
− Maintenance of normal osmolality and
volume of body fluids
− Ions like Na+,Ca2+,K+,Cl- , etc affects
excitability of cells
8.
9.
10. Distribution of ions across
the cell membrane at rest
Ion ICF (mmol/L of H20) ECF(mmol/L of H20)
Na+ 1.5 150
K+ 150 5.5
Cl- 9 125
Ca2+ 0.0001 1.2
Protein anion 65 <5
Mg2+ 58 3
HCO3- 10 2.8
PO4
3- 75 4
12. Applied aspect
Infants are prone to dehydration i.e.,
infants are more vulnerable for water loss due to:
• Absolute ECF volume is lesser
• Increased body surface area compared to mass
• Higher metabolic rate
• Physiologic inability of the infant’s kidneys to
concentrate urine
see http://www.ihrdni.org/068b-022.pdf
14. Measurement of body fluid volumes
• Total body water is measured using dilution
principle.
• A marker is injected that will be evenly distributed in
all the compartments of body fluids.
• Marker that diffuses freely not only in the water
outside the cells, but also crosses the cell membrane
to reach the intracellular fluid.
15. • ECF volume is measured using substances that
cannot enter the cells, but can freely cross the
capillary membrane and thus distribute evenly in the
ECF compartments.
• Plasma volume is measured using substances that
binds specifically to plasma proteins, and will not
diffuse into the interstitium.
Measurement of body fluid volumes
I 131 ALBUMIN – SERUM ALBUMIN LABELED WT RADIOACTIVE IODINE
http://www.ihrdni.org/068b-022.pdf
Red Cell Volume Can Be Accurately Determined in Sheep Using a ...
https://www.ncbi.nlm.nih.gov › NCBI › Literature › PubMed Central (PMC)
by DM Mock - 2008 - Cited by 11 - Related articles
RCV determination by (14C)cyanate, 51Cr, and (125I)streptavidin. For each sample of blood obtained after infusion of the labeled RBCs, radioactivity per mL of blood was calculated and was plotted versus time.