Symbols and Units

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Kilde : Poul-Erik_Paulev,MD

Originale kilde

Textbook in Medical Physiology And Pathophysiology
Essentials and clinical problems

Chapter Symbols and Units

Emne: Fysiologi

  • Cellular Physiology

Cells And Action Potentials
Muscle cells and disorders

  • The Nervous System

Somatosensory system and disorders
Brain function, locomotion and disorders
Special senses and disorders
Autonomic system and disorders
Neurological and psychiatric disorders

  • The Circulatory System

Cardiovascular physiology and disorders
Systemic resistance and disorders
Cardiac performance and disorders
Cardiac action potentials and disorders
Bloodflow, distribution and shock

  • The Respiratory System

Mechanics of breathing
Pulmonary gas exchange and disorders
Blood gas transport and disorders
Control of respiration. High altitude
Acid-base balance and disorders
Exercise, sports and doping
Flying, space life and diving

  • Metabolism and Gastrointestinal Function*

Metabolism and nutritional disorders
Thermoregulation, temperature and disorders
Gastrointestinal function and disorders
Hepato-pancreatic function and disorders

  • The Kidneys And The Body Fluids

Body fluids and their regulation
Renal physiology and disease

  • Endocrine Glands

The hypothalamo-pituitary system and ectopic hormones
Blood glucose and diabetes
Thyroid hormones and disorders
Sexual satisfaction, reproduction and disorders
Other hormones and disorders
The human genome and genetic disorders
Immunology and immune system disorders
Infectious disorders

 1.        Force is measured in Newton (N). One Newton (kgm s-2) is the force required to accelerate a mass of 1 kg with an acceleration of 1 m s-2. The acceleration due to gravity is generally accepted as g or G = 9.8067 or 9.807 m s-2.

 2.        Joule established already in 1848 that mechanical work and heat ener­gy were interchangeable. The commonly used unit of energy is the calorie (cal), which is the energy, required to raise the temperature of 1 gram (g) of water from 14.5 to 15.5oC. Work is force times distance, and it is measured as Newton-meter or Joule (J). The Joules equivalent has been determined to be 4.187 J ca­l-1.

 3.        Finally, work-rate or power is calculated as work­ per second (s). The power unit 1 W equals 1 J s-1.

 4.        Pressure is measured as force per area unit that is in N m-2 or Pascal.

In the gravity field of the earth G or g equals 9.807 m s-2. Blood and sea water has a relative density of 1033 kg m-3. A 10 m high sea water column resting on one square m, corresponds to the following pressure: (10 m × 1033 kg m-3 × 9.807 m s-2) =

101 306.3 (kg m s-2) m-2. This is 101 306.3 N m-2 or 101.3 kPa (= 1 atmosphere). The classical concept is that 1 atmosphere equals 760 mmHg. Accordingly, 1 Torr or 1 mmHg equals (101 306.3 Pa/760 =) 133.3 Pa. In this book pressures are given in Pa (or kPa) together with mmHg.

 5.        Concentration is mass per volume unit. Squared brackets around a substance or C denote concentration. The international unit is mM = mmol l-1 = mol m-3.

 6.        A prefix scale for different units is used as follows: milli = m = 10-3; micro = m = 10-6; nano = n = 10-9; pico = p = 10-12; femto = f = 10-15.

<a name="International Symbols">International Symbols</a> 

(Fed.Proc. 9: 602-605, 1950).

This is a precise short-cut for intellectual transfer used by all physiologists.

A dash next to any symbol (-) indicates a mean value. A dot next to any symbol (.) denotes a time derivative. Small letters in a suffix denote gas dissolved in blood, whereas large letters denote gas in air. The symbol is often the first letter in the English word. 

a  = Solubility: The Bunsen solubility coefficient (ml STPD per ml fluid per 760 mmHg) 
A = Alveolar gas
AA = arachidonic acid
Ach = acetylcholine
ACTH =  adrenocorticotropic hormone
Ad =  adrenaline
ADH = antidiuretic hormone
ADP = adenine diphosphate
AIDS =  acquired immunodeficiency syndrome
AMP = adenine monophosphate
AMPA = special glutamate receptors
ANF = atrial natriuretic factor
ANH/ANP = atrial natriuretic hormone/peptide
AP =  action potential
AR = absolute refractory period
ASA = acetylsalicylic acid
ATP = adenine triphosphate
ATPS = ambient temperature, pressure, saturated with water vapour
AV node = atrioventricular node
BB = buffer base
BD =  base deficit
BE =  base excess
BMR =  basal metabolic rate
BSA = body surface area
BTPS = body temperature and ambient pressure, saturated with water vapour
C = concentration of gas in blood. Squared brackets around a substance also denote concentration
Cal = calorie
Cv_CO2 = concentration of CO2 in mixed venous blood
CA = carbonanhydrase
cAMP = cyclic adenine monophosphate
CBF = cerebral bloodflow
CBG = corticosteroid binding globulin
CCh = carbacholine
CCK = cholecystokinin
cGMP = cyclic guanosine monophosphate
CNS = central nervous system
CSF = cerebrospinal fluid
COLD =  chronic obstructive lung disease
COMT = catechol-O-methyl transferase
C peptide = connecting peptide
CRH = corticotropin releasing hormone
CVP = central venous pressure
D = diffusion capacity
Da = Daltons (MW units)
DAG = diacylglycerol
1, 25-D3 =  1,25-dihydroxy-cholecalciferol
25-OH-D = 25-hydroxy-cholecalciferol
DIT = di-iodine-thyronin
DM = Diabetes mellitus
DMNV = dorsal motor nucleus of the vagus
DMPP = dimethylphenylpiperazine
DNA = deoxyribonucleic acid
DOPA = dihydroxy-phenylalanine
2,3-DPG = diphosphoglycerate
DPPC = dipalmitoyl phosphatidylcholine
E = expiration
Enet  = mechanical net-efficiency of external work
EAA =  excitatory amino acids
ECG = electrocardiogram
ECF = extracellular fluid
ECV = extracellular fluid volume
EDIP =  end-diastolic intraventricular pressure
EDRF = endothelium-derived relaxing factor
EDTA = ethylene-diamine-tetra-acetate
EEG = electroencephalogram
EF = excretion fraction
EGF =  epidermal growth factor
e.p. = equilibrium potential
EPSP = excitatory postsynaptic potential
ER = endoplasmic reticulum
ERBF = effective renal blood low
ERPF = effective renal plasma flow
ERV = expiratory reserve volume
ESV = end systolic volume
F = fraction of gas in dry air or force
f = respiratory frequency (breath/min)
FABP = fatty acid binding protein
FAD = flavine adenine dinocleotide
FADH2    = flavine adenine dinucleotide (reduced)
FFA =  free fatty acids
FGF = fibroblast growth factor
FRC = functional residual capacity (= RV + ERV)
FSH =  follicle stimulating hormone
FU = Flow units in ml of blood (100 g tissue)-1 min-1
G = Gibbs energy (free, chemical energy)
GABA = gamma-aminobutyric acid
GFF = glomerular filtration fraction
GFR = glomerular filtration rate (normal 118-120 ml min-1)
GH = growth hormone
GHIH = growth hormone inhibiting hormone
GHRH = growth hormone releasing hormone
GIP = gastric inhibitory peptide or glucose-dependent insulin-releasing peptide
GLP = glucagon-like peptide
GnRH = gonadotropin releasing hormone
GLUT = glucose transporter
GRP = gastrin releasing peptide
GTP =  guanosine triphosphate
H = heat content (enthalpy; all energy when the pressure-volume work is zero)
Hb = haemoglobin (haemoglobin F = foetal haemoglobin)
HBF = hepatic blood flow
hCG = human chorionic gonadotropin
HDL = high density lipoprotein
HGF = hepatocytic growth factor
HGH = human growth hormone
HIP = hydrostatic indifference point
HIV = human immunodeficiency virus
hPL = human placental Lactogen
HPLC =  high pressure liquid chromatography
HSS = hepatocyte stimulating substance
I =  inspired gas
ICSH = interstitial cell stimulating hormone
ICV =  intracellular fluid volume
IDDM = insulin-dependent diabetes mellitus
IDL = intermediate density lipoprotein
IGF = insulin-like growth factor
IGF-BP = IGF-binding protein
IP3   = inositol triphosphate
IRV = inspiratory reserve volume
ISF = inter­stitial fluid (tissue fluid)
Iso = isoprenaline
ISS = interpreted signal strength
i.v. = intravenous
J = flux of a substance (mol min-1) through an area unit
J = Joule
JG = juxtaglomerular
K = Kelvin degrees of temperature
LAT = lactic acid threshold
LBNP = lower-body-negative-pressure
LES = lower oesophageal sphincter
LH = luteinizing hormone
LHRH = luteinizing hormone releasing hormone
LPL = lipoprotein-lipase
LDL = low density lipoprotein
LTH = prolactin
LVET = left ventricular ejection time
MAO = monoamine oxidase
MAP = mean arterial pressure/mean aortic pressure
MeCH = metacholine
MEOS = microsomal ethanol oxidation system
MG = monoglycerides
2MG = 2-monoglyceride
MIH = Muller inhibiting hormone
MIT = mono-iodine-thyronin
mM = mmol l-1
MR = metabolic rate
MSH = melanocytic stimulating hormone
MW = molecular weight (in Daltons)
N = Newton
NA = noradrenaline
NAD = nicotinamide adenine dinucleotide
NADH2  = nicotinamide adenine dinucleotide (reduced)
NANC = non-adrenergic, non-cholinergic
NBB = normal buffer base/neutral brush border
NGF = nerve growth factor
NIDDM = non-insulin-dependent diabetes mellitus
NMDA = N-methyl-D aspartate
NOS = nitric oxide synthase
NSAID = non-steroid anti-inflammatory drug
P = partial pressure of gas in air or blood
PAH = para-amino hippuric acid
PCV = packed cell volume
PDE = phosphodiesterase
PDGF = platelet derived growth factor
PEF =  peak expiratory flow
PG =  prostaglandins
PG2 = prostacyclin
PGE2 =  prostaglandin E2
PIF = prolactin inhibiting factor
PIP2    = phosphatidyl-inositol diphosphate
PB    = barometric pressure
Pc'CO2 = partial pressure of CO2 in end-capillary blood
PIO2 = partial pressure of O2 in inspired air in trachea 
PaO2 = partial pressure of O2 in arterial blood
POMC = pro-opiomelanocortin
PP = pancreatic polypeptide/ pulse pressure amplitude
PRL = prolactin
PRU = pressure resistance unit
PTH = parathyroid hormone
PVR = pulmonary vascular resistance
Q°   = Cardiac output (l min-1)
QRS =  the ventricle complex of the ECG
R =  ventilatory exchange ratio (pulmonic)
R = Gas constant
RAS = reticular activating system
RBF = Renal bloodflow
RC =  respiratory controller/ respiratory centres
REM = rapid eye movements
RES = reticulo-endothelial system
RIA = radio-immuno assay
RMP = resting membrane potential
RNA = ribonucleic acid
RPF = renal plasma flow
RPM = revolutions per minute
RQ = respiratory quotient (metabolic)
RR = relative refractory period
RV =  residual volume
S = entropy (the tendency to spread in a maximum space)
S = saturation degree
SA = specific activity
SAmode = sinoatrial node
SB = standard bicarbonate concentration
SBE = standard base excess
SDA = specific dynamic activity
SR = sarcoplasmic reticulum
SS = steady state/ stimulus strength
STPD = standard temperature and pressure, dry (0oC, 760 mmHg)
STN = solitary tract nucleus
sv = stroke volume
T = tension (force)
T =  temperature
T3  = Tri-iodo-thyronine
T4  = tetra-iodo-thyronine
TBA =  thyroxine-binding albumin
TBG = thyroxine-binding globulin
TBPA = thyroxine-binding prealbumin
TBV =  total blood volume
TCA = tri-carboxylic acid
TEV =  total erythrocyte volume
TFGF = transforming growth factor
TG =  triglycerides
TGF =  tubuloglomerular feedback
TH = total haemoglobin content
TLC = total lung capacity (=RV+VC)
TP = threshold potential
TPVR =  total peripheral vascular resistance
TRH = thyrotropin-releasing hormone
tRNA = transfer RNA
TSH = thyroid-stimulating hormone
TV =  tidal volume
TxA2 =  thromboxane A2
v dash = linear mean velocity
V°   = volume velocity of gas
V = volume
V°A   = expired alveolar ventilation (l min-1)
VC = vital capacity (=IRV+TV+ERV)
VD =  dead volume
W = Watts (J s-1)
W = external work (with pressure-volume work zero)

<a name="Nutritive Equivalents And Enthalpy">Nutritive Equivalents And Enthalpy</a>

Nutritive equivalents for oxygen are:

Carbohydrate 37 mmol oxygen g-1, fat 91 mmol oxygen g-1 , and protein 43 mmol oxygen g-1. On a mixed diet 20 kJ of energy is transferred per litre STPD of oxygen used; the RQ is 0.8.

Nutritive equivalents for carbon dioxide are:

Carbohydrate 37 mmol g-1, fats 64 mmol g-1, and protein 34 mmol g-1.

Metabolic enthalpies (heat energy liberated in the body per g combusted nutrient) in kJ g-1 substance: Protein 17, fat 39 and carbohydrate 17.5.

<a name=" Essential Atomic And Molecular Weights"> </a><a name=" Essential Atomic And Molecular Weights">Essential Atomic And Molecular Weights</a>

These are given in g mol-1 (or Daltons, Da) throughout the text. Calcium 40; Carbon 12; Glucose 180; Helium 4; Hydrogen 1; Nitrogen 14; Oxygen 16; PAH 194.2; Phosphorus 31; Potassium 39; Sodium 23; Xenon 131.

Physical Constants And Conversion Factors

Acceleration due to gravity (standard 1 G): 9.81 m/s2.

Avogadro's constant: 6.02 1023 molecules mol-1 .

Diffusion coefficients for most molecules: 10-10 m2 s-1 per molecule.

Energy (J = N m = Volts Coulomb): 1 cal = 4.187 J.

Farad = Coulomb/Volts.

Faraday's constant: 96 487 (104) Coulomb/mol monovalent ion.

Molar gas constant (R): 8.31 J mol-1 per degree Kelvin (K).

Specific heat capacity of the human body: 3.47 kJ kg-1  oC-1.

Energy transfer by evaporation of 1 kg of water at the usual skin temperature: 2436 kJ.

Pressure (Pascal = Pa = N m-2): 1 mmHg = 1 Torr = 133.3 Pa.

Surface tension of body warm water: 0.07 N m-1.

Temperature conversion between degrees of Fahrenheit (oF) and degrees of Celsius (oC): (oF) = 9/5 (oC) + 32.

<a name="Calculated Partial Pressures">Calculated Partial Pressures</a>

The partial pressures of respiratory gasses are calculated in the alveoli and in the surrounding air of a healthy person, resting at sea level (101.3 kPa = 760 mmHg or Torr = 1 atmosphere).

The water vapour tension in a fluid (air or liquid) of the temperature 310 K (37oC) is 6.27 kPa or 47 mmHg. At 293 K (20oC) the tension is 2.4 kPa or 18 mmHg. The alveolar gas fractions are: FAO2 = 0.15, and FACO2 = 0.056. The composition of atmospheric air is: FIO2 = 0.2093 and FICO2  = 0.0003.

PO2 = FO2 (101.3 - 6.27) kPa.

PAO2 = 13.3 kPa (100 mmHg); PaO2 = 12.7 kPa (95 mmHg); PvO2 = 6 kPa (45 mmHg).

PACO2 = 5.3 kPa (40 mmHg) ; PaCO2 = 5.3 kPa (40 mmHg); PvCO2 = 6.1 kPa (46 mmHg).

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