Specialised Connective Tissue
Structure & Function
Lect # 5
Body Fluid Compartments
Lect 4
Prof Kumlesh K. Dev
Department of Physiology
SKELETAL
CARTILAGE
Lect 3
BONE
CARTILAGE
GENERAL
BONE
CELLS
FLUID
BLOOD
FIBRES
LYMPH
GROUND SUBSTANCE
Key importance of body fluids
– Homeostasis
– Primary transport between cells: Nutrition,
Nutrition Waste
Waste, Signals
Fluid balance
– Inputs/outputs
FIBRES
Mesenchymal cells
Fibroblasts
Adipocytes (fat cells)
Immune cells
- Macrophages
- Mast cells
- Plasma cells
- Lymphocyte
- Monocyte
Outline
Lect 5
FLUID
BLOOD
CELLS
SKELETAL
GENERAL
LYMPH
GROUND SUBSTANCE
Collagen
Elastin
What’s wrong?
─ what’s additional material in
his leg?
─ Lymph
─ Water
─ Interstitial fluid
Fluid Compartments
– Volumes
– Boundaries and movement of materials
– Exchanges (Starling’s Law)
– Pathophysiology (oedema)
– Measurement/estimation of compartments
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Pathophysiology - elephantiasis
─ is problem inflow or outflow?
Lymphatic drainage
─ 3 litres per day not reabsorbed in capillaries/venules
─ enters lymph
y p vessels
Answer
─ pumped to lymph nodes
─ block lymphatic drainage
─ re-enters circulation near right atrium
─ accumulation of fluid in tissue
Sherwood 10-25
Causes
─ Parasitic worm (filaria) in
lymph vessels
─ Generic term: Lymphoedema
Normal Daily Input and Output
Inputs
• Ingestion
– Fluid (1.25 litres)
– Food (1 litre)
• Metabolism (350 ml)
Outputs
• Urine (1.5 litres)
• Breathing/Skin (900 ml)
• Gut (Faeces 100 ml)
• Sweating (100 ml)
Total 2.6 litres
Total 2.6 litres
Abnormal Input and Output
Inputs
• Clinical
– injection
– infusion
• Excessive drinking
Outputs
• Urine (diabetes insipidus)
• Breathing/Skin (burns)
• Gut (vomiting, diarrhoea)
• Sweating
g
• Heamorrhage
2
Fluid Compartments
Fluid Compartments: compositions
Total body water
(TBW)
42 litres
Total body water
(TBW)
42 lit
litres
Extracellular
fluid (ECF)
(outside cells)
14 litres
Intracellular
fluid (ICF)
(inside cells)
28 litres
Na+ low
Cl- low
K+ high
Phosphates
Proteins
(ICF = TBW – ECF)
clinically 65% TBW
Plasma
(PI)
(20%)
2.8 litres
Interstitial
fluid (IF)
(80%)
11.2 litres
Plasma
(PI)
(20%)
2.8 litres
Extracellular
Na+ high
fluid (ECF)
Cl- high
(outside cells) K+ low
14 litres
Intracellular
fluid (ICF)
(inside cells)
28 litres
Interstitial
fluid (IF)
(80%)
11.2 litres
Na+ high
Cl- high
K+ low
(IF = ECF – Pl)
Body Water
Fluid Compartments: boundaries
Compartment
Intracellular
fluid (ICF)
(inside cells)
Na+ high
Cl- high
K+ low
Na+ low
Cl- low
g
K+ high
Phosphates
Proteins
Interstitial fluid
(IF)
(environment
between all cells)
Plasma
(in blood vessels)
Volume (litres)
Mass (kg)
Body Water in a 70 kg healthy male
barrier is the
cell membrane
• selectively permeable
(blocks proteins)
• ion Na+/K+/ATPase
pump (3 Na+ out, 2 K+
in)
barrier of the
capillary wall
• permeable (to small
mols)
• rapid equilibration
between plasma and
IF
Total body water (TBW)
Intracellular Fluid (ICF)
Extracellular Fluid (ECF)
Plasma (PI)
Interstitial Fluid (IF)
42
42 kg
28
28 kg
14
2.8
11.2
14 kg
─ 1 litre H2O weighs 1 kg
─ Total body water makes us 60% of total body mass
─ Which has lower proportion of body water?
a) 80 kg normal build
b) 80 kg obese
─ Ans: 80 kg obese (Fat has less water, only 10% water)
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Starling’s Law of Capillaries
─ capillary wall permeable
─ plasma & Interstitial Fluid
interchange
Kidney
─ plasma carefully regulated
─ hence IF composition is
carefully regulated
Arteriole BP
(37 mmHg)
Colloid OP
(osmotic pressure
of plasma proteins)
( 25 mmHg)
PRESSURE
Difference
~12mmHg
Osmolarity and Osmolality
Venule BP
(17 mmHg)
PRESSURE
Difference
~8 mmHg
Liver (failure)
─ liver synthesises
y
most
plasma proteins
─ in liver failure plasma
proteins & colloid OP falls
─ reduced inward flow
─ accumulation of fluid in
tissues (oedema)
hypotonic solution
– cell gains water
– swells (may lyse)
hypertonic solution
– cell loses water
– cell shrinks
• in dilute (physiological) solution approx. same as osmolarity
Osmolarity
• concentration/litre (moles/litre) of solute particles
– Glucose 0.1 mole/litre = 0.1 Osmole
– NaCl
0.1 mole/litre = 0.2 Osmole (dissociation: Na+, Cl-)
Relative osmolarity
– Intra-/Extracellular Fluid
– Iso-osmotic
– Hyper-osmotic
– Hypo-osmotic
Relative osmolarity
• cell memb. permeable
to water (passive) but
not to solute
• thus, water moves from
lower to higher solute
conc
Osmolality
• concentration/kg (moles/kg) of solute particles
Iso-osmotic
(300 mOsm)
Hypo-osmotic
(< 300 mOsm)
= 300 milli-Osmoles (mOsm)
= 300 mOsm
> 300 mOsm
< 300 mOsm
Fluid Replacement
Hyper-osmotic
(> 300 mOsm)
• Haemorrhage
– Replace blood with
isotonic saline (NaCl)
– No change in cell
volume
• Sports drinks
– Replace water and
ions
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Learning Outcomes – (Lessons 9)
To be able to:
• a) describe different fluid compartments of body and outline principles of their measurement
• b) state approximate volumes of major compartments of body water
• c) describe movement of water and other molecules between compartments
• d) list various forms of water input/output and state which are subject to physiological regulation
• e) explain role of plasma proteins in movement of fluid across capillaries
• f) describe differences in composition of different compartments
Intracellular (ICF) — high [K+], low [Na+]; PrInterstitial (IF) — high [Na+], low [K+]
Plasma — as IF, plus Proteins
• explain compartment compositions & boundaries
ICF/IF — cell membrane: semipermeable, Na+/K+ pump
Plasma/IF — capillary wall: bulk flow (not proteins)
• explain importance of movement of material between compartments
Plasma/IF —plasma closely regulated (kidney) hence IF regulated
ICF/IF — cell membrane regulates ICF
• g) explain flow of water/solutes (bulk flow) between plasma and interstitial fluid
• h) explain pathophysiological changes in body fluids (oedema)
• i) explain difference between osmolarity, osmolality and tonicity
osmotic effect on cell volume of solutions of different concentrations of non-penetrating solute:
hypertonic—
cell loses water
Lect
05 - Connective
- Fluids
• Tissue
j) describe
regulation and significance of composition of Plasma
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