Inner Environment Flashcards
Isovolemia
Constant volume
Isotonia
Constant osmotic pressure
Isoionia
Constant ion composition
Isohydria
Constant pH
The ‘flickering cluster’ is used to describe…
The quarternary order of water
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What are the most important functions of water?
- Solvent; a medium for reactions
- Source of osmotic forces
- Comparment and form
Give the water content of blood
90%
Give the water content of liver, muscle and brain
70-75%
Give the water content of bone
25%
Give the water content of fat
10%
Give the barriers separating compartments
Cell membranes
Capillary walls
Cell membrane
- Permeable for water without restriction
- Selective for every other substance
Capillary wall
- Retains colloids
- Permeable for every other substances
- >50,000 daltons cannot pass through capillary wall
Which parts of the membrane determine transport?
- Lipid double layer
- Complex proteins:
- Receptors
- Enzymes
- Carriers
- Channels
What are the types of membrane transport?
- Passive transport:
- Simple diffusion
- Facilitated diffusion
- Active transport:
- From direct energy source
- From indirect energy source
What is the ratio of extracellular water to intracellular water in the body?
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Total body water (TBW) =
Extracellular compartment + Intracellular compartment
600-650 ml/bwkg
What are the subcompartments of the EC space?
- Intravasal (circulation)
- Tissues (interstitial)
- Transcellular (seperated by epithelial cell layers)
Give examples of transcellular extracellular subcompartments
- Synovial fluid
- Aqueus humour
- Glandular discharges
- Urinary bladder contents
- Gastrointestinal tract
- Rumen
Intravascular water is divided into…
- Plasma water
- Blood cells
Interstitium water is split into…
- Soft tissues
- Fibrous connective tissue
- Bone tissue
What proportion of body water is in plasma water?
45 ml/bwkg
What proportion of body water is in blood cells?
35 ml/bwkg
What proportion of body water is in soft tissue?
120-150 ml/bwkg
What proportion of body water is in bone tissue?
45 ml/bwkg
What proportion of body water is in fibrous connective tissue?
45 ml/bwkg
What proportion of water is in the Interstitium?
250 ml/bwkg
What proportion of water is in the Trancellular compartment?
15 ml/bwkg
When measuring the EC compartment by dilution principle, what are the two phases of dilution of indicator in the extracellular space?
- Quickly equilibrating space
- Fast (0.5 - 1 hour)
- Bloody plasma
- Interstitium
- Lymph
- Slowly equilibrating space
- Uniform distribution (8-10 hours later)
- Bone
- Transcellular space
What is the formula for Stewart dilution principle in a living organism?
- S = Substance*
- C0 = Calculated original concentration*
- V = Volume*
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Give the graph for the Stewart dilution principle
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The intracellular compartment is considered to be…
Uniform
even though it contains a number of small compartments
What is the green arrow indicating?
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Outflow
What does this graph show?
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Concentration of indicator with time
Shows EC fluid distribution from the compartment at differnet rates
What is the green arrow indicating?
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Backflow
What is the green arrow indicating?
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Slow excretion
What is used to quantify volume of the EC space?
Sterwart dilution principle
How does the concentraion of indicater change in a living organism?
It decreases constantly
- Permeate barriers
- Metabolised
- Excreted by kidney, lung or skin
Extrapolation of the concentration/time graph allows…
Extrapolation of data to calculate the C0
What is assessment of total body water based on?
Dilution principle:
- 3H2O
- 2H2O
- Antipirina
- Urea
- Thiourea
What is exsciccation?
Dessiccation until a constant mass is reached
at 105°C
“in vivo”
“Within the living”
What does the green arrow show?
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Fast distribution
C0 (f)
shows the volume of the soft tissues
What does the green arrow show?
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Slow distribution
C0 (s)
Shows the volume of the soft plus fibrous tissues
What does the green arrow show?
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Late distribution
C0 (l)
Shows the volume of the soft, fibrous and bone tissues
Formula to calculate density
m/V
Density of bone
1.56 g/ml
Density of soft tissue
1.06 g/ml
Density of fat
0.94 g/ml
As % fat in the body increases, TBW…
Decreases
How is quantification of the EC compartment measured?
Substances observed diffusing accross the capillary wall
These do not cross the cell membrane
Which substances are suitable for Quantification of the EC compartment?
- Inulin
- Mannitol
- Sacharose
- Isotopes of EC ions
- Na+
- Cl-
- Br-
How can the intravascular compartment be quantified?
Substances do not cross the capillary wall
Do not cross the cell membrane
Which substances are suitable for measuring the proprotion of body water in plasma?
In albumin, globulin or fibrinogen:
- Evans blue
- 131 v. 125 iodine
Quantity of Intracellular component =
Total Body Water - Extracellular Compartment
Quantity of Interstitial volume =
Extracellular volume - Intravasal volume
Symptoms of Isoosmotic hypovolemia
- Hemorrage
- Burn
- Vomiting
- Diarrhoea
Symptoms of Hyperosmotic hypovolemia
- Hydropenia: Decreased intake
- Increased loss
- Increased evapouration
- Diabetes insipidus
Symptoms of Hypoosmotic hypovolemia
- Decreased salt intake
- Primary salt loss
- Sweating
- Hypoadrenocorticalismus (Salt loss through kidney)
Give the three types of dehydration/hypovolemia
- Isoosmotic hypovolemia
- Hyperosmotic hypovolemia
- Hypoosmotic hypovolemia
Give the three types of Hyperhydration/Hypervolemia
- Isoosmotic hypervolemia
- Hyperosmotic hypervolemia
- Hypoosmotic hypervolemia
Symptoms of Isoosmotic hypervolemia
- Oedema
- Overdose physiological saline
- per os (through mouth)
- Parenterally
Give the symptoms of Hyperosmotic hypervolemia
Hyperosmotic fluid intake orally or parenterally
Symptoms of Hypoosmotic hypervolemia
- Exaggerated water uptake
- Water retention in the kidney (ADH overproduction)
Time taken for IC and EC isoosmosis to form
30 minutes
Time taken for isovolemia to restore
2 days
‘Milieu interieur’
- “The living organism does not live in an outer environment but in its own fluid environment”*
- Claude Bernard