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[body.CVS.heart.rate]
Heart rate, or pulse, is the  number of heart beats per minute (72 /min).
Influenced by
AP (baroreceptor reflexes) strongly,
SYMP (sympathetic nerves and circulating catecholamines), and [not yet implemented]
body.TEMP (direct effect on pacemaker)
RAP (Bainbridge effect)

[body.CVS.heart.SV]
Stroke volume (80 ml) is the volume of blood expelled by each ventricle in each beat.
Mainly controlled by filling pressure ( LAP and RAP , via Starling's Law,  dependent on body.CVS.heart.left.starling ),
but also increased SYMP (sympathetic nerves and circulating catecholamines) and adrenergic drugs.
If SysBP is to high, there it is reduced due to incomplete emptying of the ventricle.
Severe acidosis (low pH ) impairs cardiac function. 
If there is AorticRegurgitation or MitralRegurgitation , the effective stroke 
volume is reduced as some of the pumped volume returns immediately to the ventricle. 

[body.CVS.heart.CO]
Cardiac output is rate of flow of blood around the body (5.5 l/min), i.e.
the amount of blood pumped by each side of the heart in one minute.
Equal to HR multiplied by SV .

[body.CVS.AP]
Mean arterial pressure (MAP) (86 mmHg).
Blood pressure is generated by the heart pumping against a resistance.
Because of the shape of the blood pressure waveform,  it is roughly the 
body.CVS.DiaBP plus a third of the body.CVS.pulseP .
Calculated from CO multiplied by PR .

[body.CVS.pulseP]
Pulse pressure is the difference between diastolic and systolic blood pressures. 
I.e., it relates to the arterial walls relaxing before each beat of the heart.
Depends on SV , Hard and AP

[body.icf.volume]
The amount of volume inside cells, including blood cells (45L).
Fluid enters and leaves cells by osmosis, therefore the volume 
is osmotically balanced with  body.ecf.Osm .


[body.CVS.DiaBP]
Diastolic blood pressure (80 mmHg)
Influenced by
SV
PR
arterial elasticity

[body.CVS.SysBP]
Systolic blood pressure (120 mmHg)
Influenced by
SV
PR
arterial elasticity

[body.CVS.PR]
Total peripheral resistance (PR, TPR), 
or Systemic vascular resistance (SVR) (18 mPRU, or 18 mmHg/l/min)
Calculated from the combined effects of
body.kidney.resistance ,
body.muscle.resistance ,
body.skin.resistance ,
body.viscera.resistance ,
body.brain.resistance , and
body.CVS.heart.resistance

[body.kidney.resistance]
Renal resistance (83 mPRU, or 83 mmHg/l/min)
This is proportional to AngII .
//(Used to be influenced by body.blood.Visc)

[body.kidney.flow]
Renal blood flow (1.25 l/min)
Equal to
body.CVS.AP / body.kidney.resistance

[body.muscle.resistance]
Muscle resistance (90 mPRU, or 90 mmHg/l/min)
Influenced by
muscle.O2Use
VISC
muscle.CO2
SYMP

[body.muscle.flow]
Muscle blood flow  (1.1 l/min)
Equal to
CVS.AP / muscle.resistance

[body.skin.resistance]
Skin resistance (250 mPRU, or 250 mmHg/l/min)
Vasconstriction of the skin is caused by
a fall in AP (baroceptor reflexes),
or increased SYMP .
Dilatation in response to
low body.TEMP and SKTMP
. Resistance also affected by VISC .

[body.skin.flow]
Skin blood flow (400 ml/min)
Equal to
AP / SKRES

[body.viscera.resistance]
Visceral resistance (56 mPRU, or 56 mmHg/l/min)
Influenced by
AP (baroceptor reflexes)
VISC
SYMP and
volume of food in gut.


[body.viscera.flow]
VIFLO
Visceral blood flow (1.825 l/min)
Equal to AP / VIRES

[body.brain.resistance]
Brain resistance (750 mPRU, or 750 mmHg/l/min)
Influenced by
SYMP
VISC

[body.brain.flow]
Brain blood flow (750 ml/min)
Equal to AP / BRRES

[body.CVS.heart.resistance]
Coronary resistance (340 mPRU, or 18 mmHg/l/min)
Influenced by
SYMP and
VISC

[body.CVS.heart.flow]
Coronary blood flow (225 ml/min)
Equal to
AP /
HTRES

[body.CVS.heart.right.atrialP]
Right atrial pressure (5 mmHg)
Dependent on quantity of blood in proximal veins, venoconstriction
and right ventricular function; hence on
BV (depending on venous compliance),
UPRT ,
 Symp ,
body.lungs.ITP, body.CVS.heart.pericVol , TricuspidRegurgitation
In the valsalva manoevre, an increase in reduces venous return and therefore filling.  


[body.CVS.heart.left.atrialP]
The pressure in the left atrium is the filling pressure, or preload.
Also known as 'pulmonary capillary wedge pressure', as it is measured by
blocking the pulmonary artery and measuring pressure in the lung vasculature.
It depends primarily on BV (depending on venous compliance).
If left ventricular function is impaired, it will increase.
Changes in UPRT, body.lungs.ITP, Symp and venous vasoconstrictors will influence filling pressure.
Increased PericardialVolume reduces effective filling, whereas MitralRegurgitation increases
the atrial pressure directly.

[body.CVS.heart.left.diaP]
Left ventricular diastolic pressure is the lowest pressure in the ventricle,
at the start of diastole. Calculated from 
LVESV and 
body.CVS.heart.left.diaCompliance

[body.CVS.heart.left.EF]
Left ventricular ejection fraction is the proportion of the end-diastolic volume
that is pumped out of the ventricle during systole. It is a good measure of how
efficiently the heart is working.
Depends on LVEDV and LVESV

[body.CVS.heart.right.EF]
Right ventricular ejection fraction is the proportion of the end-diastolic volume
that is pumped out of the ventricle during systole.
Calculated as 1 - RVESV /  RVEDV .

[body.CVS.heart.left.diaV]
Left ventricular end-diastolic volume depends on LAP and on the diastolic
compliance of the ventricle, body.CVS.heart.left.diaCompliance.gradient . 
It is also reduces with faster HR 
(according to body.CVS.heart.left.fillingCurve )
 and MitralStenosis .

[body.CVS.heart.right.diaP]
Right ventricular diastolic pressure is the lowest pressure
in the right ventricle, at the start of diastole. calculated from 
RVESV and body.CVS.heart.right.diaCompliance 


[body.CVS.heart.right.diaV]
Right ventricular end-diastolic volume depends on RAP and the diastolic
compliance of the ventricle, body.CVS.heart.right.diaCompliance.gradient .
It also reduces with faster HR (according to body.CVS.heart.right.fillingCurve )
 and TricuspidStenosis .

[body.CVS.heart.left.sysP]
Left ventricular systolic pressure is the maximum pressure. This is calculated
from SysBP and body.CVS.heart.aorticStenosis .

[body.CVS.heart.left.sysV]
Left ventricular end-systolic volume is the residual amount of blood in the
left ventricle after contraction. It is calculated as LVEDV - SV .

[body.CVS.heart.right.sysP]
Right ventricular systolic pressure is the maximum pressure. In the absence of
pulmonary valve disease this is equal to SPAP

[body.CVS.heart.right.sysV]
Right ventricular end-systolic volume is the residual amount of blood in the
right ventricle after contraction. Calculated as RVEDV - SV

[body.CVS.heart.left.power]
Left ventricular power - the rate of useful work done by the ventricle. Depends
on CO and PR

[body.CVS.heart.right.power]
Right ventricular power - the rate of useful work done by the ventricle. Depends
on CO and PVR

[body.CVS.heart.left.SW]
Left ventricular stroke work - the useful work done in one beat. Depends on
SV and AP

[body.CVS.heart.right.SW]
Right ventricular stroke work - the useful work done in one beat. Depends on
SV and MPAP

[body.CVS.heart.O2supply]
Rate of oxygen delivery through coronary artery. Depends on body.CVS.heart.flow and AO2

[body.CVS.heart.CI]
This is CO divided by SA .

[body.CVS.heart.pericVol]
The volume of pericardial fluid (5 ml) directly
controls the maximum value of the diastolic filling curves
of both ventricles.

[body.CVS.heart.aorticStenosis]
Narrowing of the aortic valve. Causes a
fractional reduction of the normal SV due to outflow resistance
from the left ventricle. Determines LVSP , body.CVS.pulsePressure .

[body.CVS.heart.aorticRegurg]
Leaking of the aortic valve. Causes a
fractional reduction of the normal SV due to regurgitation through
the aortic valve. Increases body.CVS.pulsePressure , ventricular filling
curve and filling pressure thus increasing LVEDV , and decreases SV compared
to what is normal for this EDV.

[body.CVS.heart.mitralStenosis]
Narrowing of the mitral valve. Causes a
fractional reduction in left ventricle's diastolic filling rate curve.
This consequently reduces SV significantly, and so increases LAP .

[body.CVS.heart.mitralRegurg]
Leaking  of the mitral valve. Causes a
fractional reduction of the normal SV , but also directly increases
LAP so that SV is in fact increased.


[body.lungs.Oedema]
The fluid collecting in the alveolar spaces within the lung, which rises with
LAP .

[body.CVS.Pcap]
Mean systemic capillary hydrostatic pressure (17.2 mmHg)
Influenced by
AP , RAP

[body.ICOP]
Interstitial colloid osmotic pressure (6 mmHg)
Determined by
EDEMA

[body.PCOP]
Plasma colloid osmotic pressure (28 mmHg)
Determined by
PPR

[body.blood.PPr]
Plasma protein (73 mg/ml)
Influenced by diet,
BV , glomerular protein leak.

[body.CVS.Oedema]
Degree of edema (100%)
Influenced by
PCAP
ICOP
PCOP - the Starling filtration mechanism.


[body.blood.HCT]
Hematocrit (45%)
Influenced by
blood.Eryth in relation to natural rate of breakdown.

[body.blood.Eryth]
Erythropoietin (100%)
Depends on long-term APO2

[body.blood.Visc]
Blood viscosity (100%)
Determined by
HCT

[body.blood.volume]
Blood volume (5 l)
Fluid is added to blood from gut ( body.gitract.stomach.volume ),
kidney reabsorbtion (dependent on body.blood.AngII ,
body.blood.Aldo and body.blood.ADH ).
Fluid is lost from the blood with
SWR
GFR
and ExhaledWaterLoss .
Kept in equilibrium with body.ecf.volume depending on Pcap.

[body.icf.volume]
Intracellular fluid volume (41 l)
Ionic contents of cells are currently taken as more or less constant,
so this depends solely on extracellular concentrations.

[body.ecf.volume]
Extracellular fluid volume (12.24 l), excluing plasma.
In osmotic equilibrium with
icf.volume and hydrostatic equilibrium with
BV . Indirectly controlled by blood.AngII .

[body.H2O]
Total body water (56 l)
Sum of
icf.volume
EH2O and
blood.volume

[body.blood.PNa]
Plasma sodium (144 mM)
Determined by equilibrium between diet,
SWR ,
kidney loss (dependent on Aldo and ADH ) and
equilibrium with ExNa

[body.blood.PK]
Plasma potassium (4.4 mM)
Determined by equilibrium between diet,
SWR ,
renal potassium loss ( dependent on Aldo and PNa ), and
ExK

[body.ecf.Na]
Extracellular sodium concentration depends on the
ingestion and excretion of sodium,
and is in equilibrium with PNa .

[body.ecf.K]
Extracellular potassium is in equilibrium with PK .

[body.blood.POsm]
Plasma osmolarity (304 mOsm)
Calculated from
PNa , PK , PGlu , PUN , PBic ,
PPR and other osmotic constituents such as
dextran when administered.

[body.blood.glucose]
Blood glucose (4 mM)
Balance between utilisation by metabolism (dependent on MBR ) and dietary intake dependent on brain.Appetite . It is buffered by ecf.glucose , glycogen and
FAT .
Some is lost in urine if the level is too high (diabetes).  In this simulation,
blood glucose is regarded as the only source of energy!

[body.blood.PBic]
Plasma bicarbonate (24 mM) is in equilibrium with
dissolved carbon dioxide ( proportional to VPCO2 ) and PHy .

[blody.blood.pH]
Blood pH (7.4)
Determined by equilibrium with
PBic and
dissolved venous carbon dioxide
(proportional to VPCO2 )

[body.icf.K]
Intracellular potassium is maintained high relative to body.ecf.K
by the sodium-potassium pump.
It remains essentially constant.

[body.icf.Na]
Intracellular sodium is maintained low compared to body.ecf.Na
by the sodium-potassium ATPase pump.
It remains essentially constant.

[body.icf.bicarb]
Intracellular bicarbonate concentration remains constant.

[body.icf.glucose]
Intracellular glucose remains constant.

[body.icf.pH]
Intracellular pH is acidic compared to blood.

[body.icf.prot]
Intracellular protein remains constant.

[body.KQ]
Total amount of potassium in the body. Potassium is mainly an
intracellular ion.

[body.NaQ]
Total amount of sodium in the body. Sodium is mainly an
extracellular ion.

[body.blood.arterial.PO2]
Arterial pO2 (100 mmHg)
Determined by exchange processes in lung. The alveolar
capillary pO2 is determined by
ATO2
VPO2
AVENT and
CO . VPCO2 also influences the binding of O2.
 The arterial pO2 may fall
significantly with any Shunt .

[body.blood.arterial.O2]
Arterial oxygen content (196 ml/l)
Calculated directly from
APO2 and
APCO2 .

[body.blood.arterial.PCO2]
Arterial pCO2 (40 mmHg)
Determined by exchange processes in lung, primarily by
*ATCO2
*VPCO2
*AVENT . Also affected by
*VPO2
*CO , and to a minimal extent
by Shunt .

[body.blood.arterial.CO2]
Arterial carbon dioxide content (485 ml/l)
Calculated from
*APO2 and
*APCO2

[body.blood.venous.PO2]
Venous pO2 (40 mmHg)
Calculated from
*VCO2
*VO2

[body.blood.venous.O2]
Venous oxygen content (145 ml/l)
Determined from
O2Use
CO
AO2

[body.blood.venous.PCO2]
Venous pCO2 (46 mmHg)
Calculated from
VCO2
VO2

[body.blood.venous.CO2]
Venous carbon dioxide content (540 ml/l)
Determined from
body.CO2Production
CO
ACO2

[body.skin.Temp]
Skin temperature (27 degC )
Influenced by
environment.Temp
skin.flow
body.Temp
SWR
HUM

[body.muscle.O2Use]
Muscle oxygen use (63 ml/min) is the amount of
oxygen actually taken up by muscle from the blood.
Calculated from muscle oxygen requirement due to
EXER plus the amount being used to pay off
the muscle.O2Debt , but limited by availability in blood
(depending on AO2 and MUFLO) ; deficit goes into
O2DBT .


[body.NMO2Use]
Non-muscle oxygen use (187 ml/min)
Calculated from
MBR , less muscle requirement.

[body.O2Use]
Total oxygen requirement (250 ml/min)
The sum of muscle.O2Use and
NMO2Use



[body.CO2Production]
CO2 production (200 ml/min)
Rate of production of CO2 from all body's
metabolism: it is calculated as the product of
body.O2Use and RQ .

[body.RQ]
Respiratory quotient (0.85) is the amount of CO2 produced
per unit O2 used in respiration. Pure carbohydrate breakdown
would give an RQ of 1.0. Depends on rate of lipid breakdown,
and therefore depends on body.Glycogen and Glu .

[body.muscle.O2Debt]
Oxygen debt (0 l)
Calculated as difference between muscle oxygen requirement and
*muscle.O2Use .

[body.blood.lactate]
Lactic acid (2-hydroxy propanoic acid) is produced by
anaerobic respiration, when muscle oxygen demand exceeds
oxygen supply. The resulting acid is released into the
blood stream.
Depends on muscle.flow, blood.arterial.O2, muscle.O2Use

[body.lungs.RespR]
Respiration rate (12 /min)
Influenced by
*blood.arterial.PCO2
*blood.arterial.PO2
*blood.pH
 and environmental factors such as voluntary breath-holding, hyperventilation, playing wind instruments

[body.lungs.TidV]
Tidal volume (50 ml)
Influenced by
*blood.arterial.PCO2
*blood.arterial.PO2
*blood.pH
 and environmental factors such as voluntary breath-holding, hyperventilation, playing wind instruments

[body.lungs.Vent]
Ventilation rate (6 l/min)
Calculated as
*lungs.TidV times
*lungs.RespR .

[body.lungs.AVent]
Alveolar ventilation rate (4 l/min)
Calculated from
lungs.Vent minus the volume of the lungs.DdSp , taken as 150 ml.

[body.XPCO2]
pCO2 in expired air (25 mmHg)
Calculated from
*blood.venous.CO2
*lungs.Vent
*air.CO2

[body.muscle.CO2]
CO2 content of muscle veins (490 ml/l)
Determined from
*Exer
*blood.arterial.CO2
*muscle.flow

[body.MBR]
Metabolic rate (2000 kcal/day)
The sum of the BMR (a function of
body.mass and
body.Temp ) and the contribution of
Exer (assumed 24% efficient); also influenced by
*blood.Thyr and Fever .

[body.Temp]
Core body temperature (37 deg C)
Heat is lost by exchange with
*skin.Temp , dependent on
*skin.flow . Heat is also lost via
*lungs.AVent , dependent on
*Hum .
Heat is produced proportionally to *body.MBR ,
and is distributed over Mass .

[body.blood.Thyr]
Thyroxine level (9.8 to 23 pM)
Dependent on long-term
*body.Temp .

[body.skin.SwR]
Sweat rate (0.5 ml/min)
Influenced by
*body.Temp and
*skin.Temp , and also
*brain.Symp

[body.skin.area]
Total body surface area is estimated from
height and weight.

[body.Fat.mass]
Total fat-mass (15 kg)
Fat is synthesised when Insul and BGlu are high, and broken down when both are low. Thus it reflects long-term
*blood.glucose level .

[body.Fat.flow]
Blood flow to adipose tissue, dependent on
body.Fat.resistance and AP

[body.Fat.resistance]
Vascular resistance of adipose tissue - constant.

[body.Mass]
Total body mass (70 kg)
The sum of
*body.ecf.volume
*body.icf.volume
*body.blood.volume
*body.fat.mass
, gut and bladder contents, and a constant representing other body mass.

[body.kidney.GFR]
Glomerular filtration rate (125 ml/min)
Depends on the hydrostatic pressure in the glomerulus (
from body.CVS.AP ,
body.kidney.resistance and VCT ) and the PCOP .

[body.kidney.urine.K]
Urinary potassium (42 mM)
Result of balance between dietary intake,
body.kidney.GFR and renal reabsorbtion.

[body.kidney.urine.Na]
Urinary sodium (118 mM)
Result of balance between
GFR and reabsorbtion.

[body.kidney.urine.Osm]
Urine osmolarity (600 mOsm)
Result of balance between
GFR and reabsorbtion.

[body.kidney.urine.pH]
Urine_pH (6.0)
Depends on the rate of H+ excretion,
which is proportional to blood.pH .
Also depends on bicarbonate reabsorption
(dependent on PBic ) and phosphate buffering.

[body.kidney.urine.Pr]
Urinary protein (0.3 mg/ml)
Taken as constant, except in disease.

[body.kidney.urine.urea]
Urinary urea nitrogen (8 mM)
Derived from
*body.blood.urea


[body.blood.baseExcess]
Base excess is the quantity of acid is needed
to be added to blood to make it neutral, once
the carbon dioxide content has been equilibrated
with air.
It is calculated from blood.venous.CO2 and blood.bicarb
concentrations.

[body.blood.urea]
Blood urea nitrogen (1.5 mM)
Derived from diet, which increases
*body.blood.PPr , and is reduced by renal excretion
*body.kidney.urine.urea .

[body.blood.Aldo]
Aldosterone (80 pg/ml)
Aldosterone is produced by the adrenals in response
to high PK and, in future, AngII . It increases potassium absorption 
in the proximal renal tubule.

[body.blood.AngII]
Angiotensin II (25 pM)
The primary function of Angiotensin II is to promote reabsorption of Na
from the proximal convoluted tubule.
Released in response to low body.ecf.volume .
(In the future, will become dependent on MacDn
and the renin-angiotensin axis.)

[body.blood.ADH]
Antidiuretic hormone (4 pg/ml)
The main function of ADH is to increase water reabsorption from the
collecting ducts. Low ADH causes dilute urine, and much water loss.
It is secreted when body.blood.POsm rises, or at very low BV .

[body.brain.Symp]
General sympathetic activity (normal: 50%)
Increased by hypoxia (low APO2 ),
hypotension (low AP ) or by fear or Pain .
It is also increased by adrenaline and
there is a direct effect of Exer .
<P>
It causes increased vasoconstrictor tone,
heart rate and stroke volume.

[body.CVS.APL]
Long-term arterial pressure is the average of recent
AP over several minutes.

[body.DOsm]
Difference in osmolarity
The osmolarity of the intracellular fluid minus osmolarity of extracellular fluid.
*body.IQ /
*body.icf.volume -
*body.ecf.Osm

[body.icf.Osm]
Intracellular ion quantity
The total quantity of intracellular ions, in moles; it is used to calculate
the osmolarity difference for osmosis.
This is a constant.

[body.BMR]
Basal metabolic rate (2 megajoules per day)
This is body energy used to produce heat, and for basic metabolic
processes such as digestion.
This is determined by the Thyr .

[body.Glycogen]
Total liver glycogen storage (2kg)
Rate of glycogen assimilation depends on
blood.glucose and blood.Insul

[body.kidney.urineFlow]
Rate of urine production.
This depends on GFR and by renal reabsorption,
as determined by blood composition,
AngII , Aldo , and ADH .

[body.kidney.MacDn]
Concentration of sodium at the macula densa
This determines renin secretion. It depends on
PNa and Aldosterone .


[body.CVS.VCT]
Vasoconstrictor tone
This is determined by cvs.AP and Symp .
It controls skin and visceral resistance.

[body.kidney.overallRenalFunction]
This represents how many viable nephrons the kidney has,
and is used to calculate the maximum GFR .
This value falls with age, and in renal failure.
100% corresponds to a normal young healthy adult,
and a value of less than 20% corresponds to
chronic renal failure.


[body.CVS.Hard]
Hardness of arteries
This is a constant for the individual.
It determines the systolic and diastolic blood pressure.

[body.lungs.DdSp]
Dead space in lung.
This is a constant

[body.lungs.XCO2]
Expired carbon dioxide level, as a percentage of
expired volume. Proportional to CO2Production ,
but depends on the lungs.Vent and inspired
environment.air.CO2 .

[body.blood.Insul]
Blood insulin concentration measured in nanomoles/L.
Continuously metabolised and synthesised.
Secreted with high blood.glucose and
gitract.stomach.volume


[body.Cals]
Total generated body heat (1.389 kCal/d)
Determined by MBR

[body.CVS.PCOP]
Plasma colloidal osmotic (oncotic) pressure
This is proportional to PPr

[body.CVS.ICOP]
ECF colloidal osmotic (oncotic) pressure
This is proportional to ecf.prot

[body.lungs.H2Oloss]
Rate of respiratory water loss
Determined by RespR , environment.Temp ,
environment.Hum


[body.blood.pH]
The pH of the blood (7.4)
It is - log10( PHy )

[body.blood.PHy]
Plasma hydrogen ion concentration.
This is determined by blood.bicarb and
blood.arterial.CO2 concentrations, using
the Hendersen-Hasselbalch dissociation equilibrium

[body.blood.Hct]
The percentage of blood that is made of red cells.
It is determined by the PV ,
and the RCM .

[body.blood.AHct]
The percentage of the blood volume that is plasma.
It is 100% - Hct .

[body.blood.bicarb]
The blood bicarbonate concentration. This
depends on urinary bicarbonate excretion,
the Henderson-Hasselbach equilibrium
(dependent on blood.pH and blood.venous.CO2 )
and on bicarbonate uptake from the gut.


[body.blood.RCM]
The red cell volume depends on the number of red blood cells
in the circulation. It depends on erythrocyte synthesis
governed by Eryth .

[body.blood.Eryth]
Erythropoietin is a hormone produced by
the kidney in response
to low body.blood.arterial.PO2
, to increase red cell production.

[body.blood.Osm]
The osmolarity of blood depends on
BNa , BK , body.blood.glucose ,
body.blood.bicarb ,
body.blood.prot , and
body.blood.urea

[body.blood.Hb]
The haemoglobin concentration in grams/litre
is dependent on the blood.Hct and the mean cell
heamoglobin.

[body.blood.prot]
Blood protein depends on diet and
blood.volume .

[body.blood.SatO2]
Oxygen saturation should lie in the range 92
to 100%, and is the ratio of blood.arterial.O2
to the maximum amount of oxygen the blood
can currently carry (depends on Hct ).

[body.blood.PV]
Plasma volume is the blood.volume multiplied by the blood.AHct .



[environment.Hyperv]
Make the patient hyperventilate by raising
this percentage. It influences RespR and TidV

[environment.bleedingRate]
Make the patient bleed at a specified rate, in
mL per minute. Bleeds when 'Is Bleeding' variable is switched on.

[environment.actions.fright]
Determines the amount of fright, when the
frighten action is performed.

[body.ecf.Osm]
Extracellular osmolarity is calculated from the
concentrations of ecf.Na ecf.K ecf.glucose
ecf.prot ecf.urea and ecf.H .
Since the quantity of intracellular ions remains pretty constant,
so this is primarily a reflection of the ecf.Osm .

[body.ecf.glucose]
Extracellular glucose is kept in balance with Glu .

[body.CVS.PVR]
Decreases with CO

[body.CVS.SysPAP]
This depends on CO and PVR

[body.CVS.DiaPAP]
This depends on CO and PVR

[body.blood.PGlu]
Plasma glucose depends on blood.glucose .

[body.blood.creat]
Blood creatinine levels determined
by protein breakdown rate vs. rate
of excretion by kidney.

[body.blood.PCreat]
Plasma creatinine levels determined
by protein breakdown rate, muscle bulk,
and GFR .

[body.blood.PUN]
Plasma urea levels depend on protein breakdown rate,
and GFR .

[body.blood.ketones]
Ketones include butylhydroxybutyrate and acetylacetic acid.
They are produced in the liver when Insul is low -
i.e. when the body is starved of glucose.

[body.kidney.urine.glucose]
Glucose is present in the urine when PGlu is high
and GFR is high.
It occurs when the rate of glucose passing through the nephron
exceeds the 'transport maximum' rate of glucose absorption
in the proximal convoluted tubule.

[body.kidney.glomerularLeak]
The glomerular leak is a flow rate corresponding to the amount
of plasma whose protein leaks into the glomerular filtrate.
It is used to simulate the nephrotic syndrome.


[body.lungs.AVent]
The ventilation of the alveoli, in litres per minute.
It is calculated from the TidV minus DdSp, multiplied by the RespR

[body.lungs.alvP.O2]
This is the alveolar partial pressure of oxygen, which depends
on air.O2 , the BarP , and the partial pressure of water
vapour in the lung (calculated from body.Temp ).

[body.lungs.alvP.CO2]
Alveolar partial pressure of CO2, which depends on air.CO2 ,
BarP , and the partial pressure of water vapour in the lung
(calculated from body.Temp ).

[body.lungs.alvV.O2]
The effective rate at which oxygen gas is delivered to
the alveoli. It is calculated from lung.alvP.O2 as a proportion
of BarP , multiplied by AVent .

[body.lungs.alvV.CO2]
The effective rate at which CO2 gas is delivered to
the alveoli from inspired air. It is calculated from lung.alvP.CO2 as a proportion
of BarP , multiplied by AVent .

[body.lungs.lungVolume]
This is the total volume of air in the respiratory tract. After normal expiration
at rest, this is equal to DdSp plus FRC . It is determined dynamically by
body.lungs.flow

[body.lungs.flow]
Airway flow depends on the difference of pressure between BarP and ITP


[body.lungs.Pairway]
The pressure applied by the respiratory muscles for ventilation
(or the pressure exerted by a ventilator at the airway).
This varies during the
respiratory cycle. During spontaneous ventilation, it is estimated from the
required TV, the
required inspiratory time (from IER and RespR ), Compl , and Raw .
In BIPAP it is fixed at one of two levels.

[body.lungs.ITP]
Intrathoracic pressure is the pressure in the pleural space and mediastinum.
It is negative at rest,
keeping the lungs stretched (against their
natural elastic tendency to collapse). It is determined by Paw .



[body.lungs.FRC]
The amount of air that remains in the lung after a normal expiration and is
involved in gas exchange. This is a constant for a given person, and depends
on age, sex, and lung disease.


[body.brain.O2Supply]
The rate at which oxygen is delivered to the brain.
It is the product of AO2 and BrFlo .

[environment.Hmrg]
Haemorrhage

[What?]

\~3O2+~6                Oxygen consumption (250 ml/min)~7
Rate of consumption of oxygen from the atmosphere: depends on ~3AVENT, O2-, CO, ATO2, ATCO2~7.


\~3DADR~6               Sudden fright ~7





\~3AMYL~6                Amyl nitrite~7


\~3DRH2O~6              Drink water~7


\~3INH2O~6              Water infusion~7


\~3DRSEA~6              Drink seawater~7


\~3INSAL~6              Isotonic saline infusion~7


\~3DRSAL~6              Drink isotonic saline~7


\~3INPL~6               Plasma infusion~7


\~3INBL~6               Blood transfusion~7


\~3DRBL~6               Drink blood~7


\~3INDX~6               Isotonic dextran infusion~7


\~3DRDX~6               Drink isotonic dextran~7


\~3EAT1~6               Eat standard meal~7


\~3STRV~6               No food permitted~7


\~3NBM~6                Nil by mouth~7

[environment.Exer]
Exercise (0 J)
Exercise is specified in terms of the actual external work done, in Joules.

To get your bearings, recollect that 3600 J/min
is 60W - i.e. what is needed to light an ordinary
light-bulb.  1 Horse-power is about 45 kJ/min.

Taking muscular efficiency at 24%, 3600 J/min
increases the metabolic rate by 15kJ/min
(compared with a resting BMR of 5.8kJ/min).


[environment.air.O2]
Percent oxygen in atmosphere (20%)
[environment.air.CO2]
Percent  CO2 in atmosphere (0%)
[environment.Temp]
Ambient temperature (20 degC)

[environment.Hum]
Atmospheric humidity (0%)

[environment.BarP]
Barometric pressure (760 mmHg)

760 mmHg is the normal value at sea level; 330 mmHg is equivalent
to an altitude of 6000 m, and the highest human habitations;
230 mmHg is the top of Mt. Everest (you will need an increased ATO2!);
120 mmHg (13500 m) is the maximum altitude possible breathing 100% oxygen.
At 47 mmHg your blood boils.


[environment.Uprt]

100% means fully upright; 50% is lying down flat; 0% is upside-down.
These positions are generated passively:
 Uprightness has no influence on EXER , and esentially only
affects RAP and the apparent baroceptor pressure.

[environment.Togs]
Clothing index.
Determines thermal insulation and
impedes evaporation of sweat.
 
[body.brain.thirstiness]
This modulates the desire to drink. 100% is
the normal; 0% stops spontaneous drinking, and 200%
doubles the sensitivity of the thirst centre.

[body.brain.greed]
This modulates the desire to eat. 100% is the
normal; 0% stops spontaneous eating, and 200%
doubles the sensitivity of the hunger centre.

[body.brain.pain]
The amount of pain experienced. This depends on
the environment.pain, and on analgesic drugs.

[environment.pain]
Allows simulating inflicting pain. 80% is the
equivalent of an amputation


//[environment.actions.colloidBolus]
//Infuse a rapid 500 ml bolus of colloid (protein or starch solution).


[environment.food.Na]
Salt conentration of food. Yhe amount of salt in the diet,
along with renal excretion ( UNa ), determines determines
NaQ . Sodium is initially absorbed into blood, along with water.

[environment.food.K]
Potassium conentration of food. Yhe amount of potassium in the diet,
along with renal excretion ( UK ), determines determines
KQ .

[environment.food.bicarb]
Bicarbonate in food replenishes the body's organic buffer.

[environment.food.glucose]
Sugar concentration of food determines the
energy content of each meal.

[environment.food.prot]
Protein conentration of food. Dietary protein is converted into
amino acids and is used to
replace the continual protein breakdown occuring in the
liver (excreted as UUN ).

[environment.food.solids]
Food fibre percentage: the percentage by volume of
undigestible fibre.


[environment.poo.solids]
Stool solids - arises from fibre in diet.

[body.lungs.Shunt]
The functional shunt is the fraction of the cardiac output that
travels from the pulmonary artery to the
pulmonary vein without participating in gas exchange.



[body.brain.hunger]
The current level of feeling hungry. Gradually increases
as body.blood.glucose is low, if StVol is empty, or when Insul is low. 
It falls every time a meal is eaten.
The rate of rise is modulated by body.brain.greed .

[body.brain.thirst]
The current level of feeling hungry. Gradually increases
when BVol is low or POsm is high. It falls every time water is drunk.
The rate of rise is modulated by body.brain.thirstiness .

[body.brain.sedation]
Causes feeling drowsy or becoming unconscious.
Influenced by opiates, GABA-ergic drugs, raised
APCO2 , and body.brain.hypoxia

[body.brain.hypoxia]
The deficiency of oxygen supply to the brain.
Occurs if oxygen delivery (
body.brain.flow x body.blood.arterial.O2 )
&lt; 35 ml/min, or if body.blood.arterial.PO2
&lt; 55 mmHg.

[body.brain.nausea]
Nausea occurs when
body.gitract.stomach.volume &gt; body.gitract.stomachCapacity
or if body.gitract.stomach.Na is high, or
body.blood.urea is &gt; 40 mmol/L, or
is induced by opiates.

[body.blood.NH3]
Blood ammonia concentration (41 umol/L)
represents toxic nitrogenous waste products
that are metabolised in the liver.
Influenced by gitract.stomach.prot
and body.gitract.metabolicFunction

[body.brain.fever]
Increases the temperature set-point of SkRes and SwR ,
increases MBR and catabolism of PPr .
Induced by giving drug Interferon.


[body.lungs.compliance]
The amount of air in the lungs (lung volume) depends on the pressure difference
between the outside and inside of the lungs.
The compliance of lung tissue is the constant that determines how much lung volume
changes for a given change in pressure difference.
It is determined by age, smoking, and is sometimes increased in pneumonia.

[body.lungs.airwayResistance]
This constant determines the airflow into the lungs given the
pressure difference across the airway. It depends on age but is increased in
asthma and obstructive lung disease.

[body.lungs.IEratio]
The specifies the amount of time spent in inspiration, as a fraction of the
respiratory cycle period. E.g. for an I:E ratio of 1:2, use 0.333.

[body.brain.respiratoryDrive]
Calculated as the product of O2RespiratoryDrive , CO2RespiratoryDrive and pHRespiratoryDrive .

[body.blood.CO]
Arterial carboxyhaemoglobin fraction, calculated from environment.air.CO ,
APO2 , and the relative affinity of blood for carbon monoxide compared to oxygen.

[body.lungs.expired.CO]
The percentage of carbon monoxide in expired air. Dependent on body.blood.CO
, APO2 , environment.air.CO , body.lungs.DdSp

[environment.air.CO]
Atmospheric carbon monoxide percentage.

[body.gitract.glucoseTolerance]
Pancreas tolerance to glucose - 100% gives normal insulin
secretion, and 0% is an individual who is unable to produce insulin.

[body.gitract.stomach.volume]
Volume of fluid in the stomach. If it rises above 
body.gitract.stomachCapacity it contributes to nausea.


[body.CVS.lymphaticPressure]
Pressure in the lymphatic system (0 mmHg). Increased by excess body.ecf.volume
due to oedema, and stimulated by Exer .

[body.CVS.heart.ischaemia]
If uses more oxygen than permitted by the coronary blood flow, angina results.
The deficit in coronary oxygen supply, calculated as body.CVS.heart.VO2 - 
( body.CVS.heart.flow x body.blood.arterial.O2 )

[body.CVS.heart.LVH]
Ventricular wall thickness can increase if cardiac workload 
remains high in the long term.

[body.CVS.heart.VO2]
Cardiac oxygen demand.
This is proportional to the rate the heart is doing work,  CO times AP .
