dr. jitendra patel (mbbs, md) · 3 dr. jitendra patel (mbbs, md) medical educator & researcher...
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Dr. Jitendra Patel (MBBS, MD)
Medical Educator & Researcher
Associate Professor, Department of Physiology
Email: [email protected] Web: www.esphys.weebly.com
OUTLINE
1. Composition of body
2. Functions of body fluid
3. Body fluid compartments and its Measurement
4. Ionic composition and units of measuring solutes
5. Fluid homeostasis
6. Applied Physiology
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Composition
In adult male,
Protein =18%
Fat =15%
Mineral =7%,
Water =60%.
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Water is the principal body
fluid & essential for life
Functions of body fluid
Facilitate the transport;
[nutrients, hormones, proteins, & others]
Aid in removal of cellular metabolic wastes
Provide medium for cellular metabolism
Regulate the body temperature
Provide lubrication of musculoskeletal joints.
Component in all body cavities
[parietal, pleural… fluids]
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Body Water Distribution
Extracellular fluid-14L
(20% body wt)
Plasma-3.5 L
(5% body wt)
Lymph & Transcellular fluid
Total Body Water-42L
(60% body wt)
Intracellular fluid-28L
(40% body wt)
Interstitial Fluid-10.5L (15% body wt)
Key: Wt=weight
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• Lower values in females [ More Fats]
• Decreases with age
Dehydration is more common and rapid in children
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Indicator dilution method 11
A1 – A2
V =
c
V – volume of fluid compartment
A1 – amount of indicator injected in fluid
A2 – amount of indicator removed by excretion & metabolism
C – concentration in the fluid
Prerequisites of indicator for accurate body fluid compartments
Non-toxic
Should mix evenly
Easy measurement of concentration
No effect on distribution of other substances
Should remain unchanged
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Body fluid
compartment Name of indicators
Total body
water
Radioactive water (tritium, 3H2O) or heavy water (deuterium, 2H2O) , antipyrine
Extracellular
fluid 22Na, 125I-iothalamate, thiosulfate, inulin
Intracellular
fluid (Calculated as total body water - Extracellular fluid volume)
Plasma volume 125I-albumin, Evans blue dye (T-1824)
Blood volume 51Cr-labeled red blood cells, or calculated as blood volume =
Plasma volume/(1 - Hematocrit)
Interstitial
fluid (Calculated as extracellular fluid volume - Plasma volume)
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Body fluid
compartment Name of indicators
Total body
water
Radioactive water (tritium, 3H2O) or heavy water (deuterium, 2H2O) , antipyrine
Extracellular
fluid 22Na, 125I-iothalamate, thiosulfate, inulin
Intracellular
fluid (Calculated as total body water - Extracellular fluid volume)
Plasma volume 125I-albumin, Evans blue dye (T-1824)
Blood volume 51Cr-labeled red blood cells, or calculated as blood volume =
Plasma volume/(1 - Hematocrit)
Interstitial
fluid (Calculated as extracellular fluid volume - Plasma volume)
ECF Vs ICF
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ECF Vs ICF (mmol/L)
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Component ECF(Plasma) ICF
Na+ 142 14
K+ 4 140
Ca2+ 1.3 0
Cl- 108 4
HCO3- 24 10
Mg+ 0.8 20
Proteins 1.2 4
Po43- 2 60
Osmolarity (mOsm/l)
290-300 290-300
pH 7.4 7.1-7.2
ECF Vs ICF (mmol/L)
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Component ECF(Plasma) ICF
Na+ 142 14
K+ 4 140
Ca2+ 1.3 0
Cl- 108 4
HCO3- 24 10
Mg+ 0.8 20
Proteins 1.2 4
Po43- 2 60
Osmolarity (mOsm/l)
290-300 290-300
pH 7.4 7.1-7.2
Unit of measuring solutes
Moles (M/mMol) –mw in grams
Equivalents (Eq/mEq)- valency
Osmolarity (mOsmol/L)
Vs
Osmolality (mOsmol/Kg)
pH=H+ conc.
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Fluid Homeostasis
Plasma ISF ICF
Comparable composition due to
high permeability of endothelium
Specific composition -
selective permeability
of membrane; active
transport mechanisms
Skin
ICF
28L
ISF
11L
Plasma
3L
Kidneys
Lungs
Endothelium
Cell membrane
GI tract
Lymphatics
Body Fluid - Gain And Loss
ECF ICF
Normal Routes of water gain and loss
INTAKE OUTPUT ml/day ml/day
Fluid intake 1,100
Food 1,000
Metabolic water 200
TOTAL 2,300
Insensible loss 700
Sweat 100
Feces 100
Urine 1,400
TOTAL 2,300
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Recalling the five main excretory organs
Recalling the five main excretory organs is a SKILL well worth knowing!
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“I honour, and shall always honour, every one
who advances the noble science of physiology.”
— Charles Darwin
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