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Misc - temp/procedures > Key equations and laws > Flashcards

Key equations and laws Flashcards

1
Q

Combine the Beer and Lambert law into one definition

A

◦ The measured absorbance for a single compound is directly proportional to the concentration fo the compound and the length of the light path through the sample

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2
Q

beer’s law

A

‣ Beers law deals the the concentration measurement - absorption or attenutation of light is proportional to concentration of the substance

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3
Q

Lamberts law

A

‣ Lamberts law deals with identification fo the pulsatile signal - ababsorption or attentuation is proportional to the distance the light has ti travel

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4
Q

Oxygen saturation equations (not fractional saturations)

A
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5
Q

Draw the equation for calculating HCO3 concentration

A
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6
Q

Joule thomson efffect

A

A gas changes temperature when it moves from higher pressure to lower pressure, and for most gasses they cool e.g. bike tire pumped = hot

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7
Q

Viscocity

A

Fluids resistance to flow

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8
Q

Newtonian fluid

A

Constant viscocity regardless of flow rate

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9
Q

Non newtonian fluid

A

Viscocity changes with flow rate

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10
Q

Surface tension

A

The result of attraction between moleciles across the surface of a liquid - as the molecules on the surface have reduced molecules to interact with compared to those deeper they form stronger bonds leaving the surface with the smallest possibel surface area for a given volume

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11
Q

Wall tension

A

Vessel wall that is an elasticated solid and the attraction between molecules across the surface of the solid (similar ot surface tension)

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12
Q

Laplace’s law

A

The larger the radius of the vessel the greater the wall tension required to withstand a given internal fluid pressure

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13
Q

What is Laplace’s equation for a spherical bubble

A
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14
Q

What is Laplace’s law for a cylinder

A
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15
Q

Work equation

A

Force applied x distance moved

Amount of energy applied to a system
ie. holding a shopping bag is not work because there is no distance moved

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16
Q

Energy definition

A

Capacity to do work
Measured in joules - the energy required to exert a force of one newton through a distance of one metre

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17
Q

Power equation

A

Work done/ time taken
Units watt (1 J/sec)
The rate at which work is done or the rate of transfer of energy

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18
Q

What is pressure by definiition?

A

Force divided by area

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19
Q

Define compliance

A

The change of volume with respect to pressure and a measure of the ease of expansion
Units metres/newton

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20
Q

Compliance equation

A

Change in volume / change in pressure

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21
Q

What is elastance

A

The opposite, or reciprocal of compliance

Chnage in pressure/change in volume

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22
Q

How to calculate the energy required to move a volume througha tube?

A

E = pressure x volume

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23
Q

How are power and flow related? (laminar)

A

If the pressure difference remains constant when E = P x V then

power = pressure x the rate of change of volume (or flow rate)

therefore since pressure is directly related to flow in laminar conditions

Power directly related to flow squared for laminar flow

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24
Q

In turbulent flow how is this related to pressure?

A

Power is directly proportional to flow ^ 3

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25
Q

Explain pressure as a concept then define it

A

Gas in a box contains millions of molecules zipping around in all directions bouncing off one antoher and off the walls, the combined effect of these collisions with the walls of the box create pressure

Pressure = force per unit of area

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26
Q

Define flow

A

the movement of gas through a tube or system

Volume / time

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27
Q

What is the conservation of flow?

A

Flow remains constant although if cross sectional area changes the velocity will also change to account for flow being conserved therefore

Q = A1 x V1 = A2 x V2

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28
Q

What is laminar flow

A

Orderly movement of a fluid that complies with a model in which parallel layers have different velocities relative to one another

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29
Q

What is the velocity profile within a blood vessel

A

Parabolic - fastest at the middle, decreasingly fast either side

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30
Q

Flow occurs when…

A

There is a difference in pressure between two points

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31
Q

What effect does resistance have on flow?

A

If resistance is increased a greater driving pressure is needed to maintain a fixed flow rate, BUT it will not prevent flow

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32
Q

Describe the relationship between flow and resistance

A

Flow = change in pressure or driving pressure / flow resistance of the tube

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33
Q

What is Ohms law

A

Current = potential difference or voltage/ resistance

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34
Q

Flow has what relationship to pressure

A

Directly proportional

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35
Q

What is resistance defined by

A

Hagen Poiseuelle law

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36
Q

What are the assumptions of the hagen Poiseuille equation

A

liquid is incompressible
Viscosity is stable
Flow is laminar

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37
Q

Hagen poiseuelle equation

A
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38
Q

What equation is this

A

Hagen Poiseulle equation

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39
Q

What is the equation for low solved for the Hagen POisuelle equation

A
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40
Q

Define turbulent flow

A

Movement of a fluid in which small scale currrents in the fluid move in irregular patterns while the overall flow is one directoin

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41
Q

What is Reynolds number?

A

A number used to predict whether turbulent or laminar flow would occur in a given system. It has no units

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42
Q

Reynaulds number equation

A
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43
Q

Reynaulds number equation

A
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44
Q

What is the unit for density

A

kg/m cubed

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45
Q

What is the unit for viscocity

A

newton x seconds/ metres cubed

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46
Q

What are the cutoffs for the Reynolds number

A

<2000 predominantly laminar
>4000 turbulen flow predominant
2000-4000 transitional with eddies and vortices

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47
Q

What effect does viscocity have on laminar flow?

A

Increasing viscocity reduces the reynolds number proportionally and therefore makes flow more laminar

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48
Q

What effect does density have on laminar flow

A

the more dense something is the hgiher the reynolds number and the more turbulent the flow will be

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49
Q

What is the COanda effect

A

fluid or gas stream will hug the convex contour when directed at a tangent to the surface

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50
Q

Explain the coanda effect

A

As has already been seen with the Venturi effect, when the water leaves the tap at speed, the flowing fluid entrains fluid (in this case air) into the stream of flow. When there is an obstruction, such as the spoon’s surface, this entrainment is dramatically reduced on the spoon side. There is a drop in pressure on the spoon side of the jet and this causes a deflection in the flow towards the spoon.

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51
Q

Define an ideal gas

A

An ideal gas has 3 conditions
- the molecules are assumed to be so far apart there is no attraction between them
- volume of the molecules themselves is negligible
- moleculears in random motion obeying newtons laws of motion

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52
Q

Avogadros law

A

equal volumes of gasses at the same temperature and pressure contain the same number of molecules

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53
Q

What is a mole

A

one mole is 6.02 x 10 ^ 23 atoms/molecules such that it represents a standard amount - it is derived from 12g of carbon

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54
Q

What is molar mass

A

the mass of 6.02 x 10 ^23 partiicles of the substance measured in g / mol

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55
Q

Daltons law

A

for a gas the total pressure is simply all the partial pressures added up

Pt = P1 + P2 + P3

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56
Q

How would you calculate the partial pressure of oxygen change between dry air at standard H20 pressures, and alveolar gas pressures?

A
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57
Q

Boyles law

A

the volume of gas is inversely proportional to its pressure at a fixed temperature

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58
Q

Describe the relationship between pressure and volume in gasses and draw a diagram to represent the same

A
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59
Q

What is Charle’s law

A

at a given pressure the temperature is directly proportional to the volume of the gas - linera relationship

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60
Q

Guy-Lussac’s law

A

the pressure of a gas is directly proportional to its temperature within a fixed volume

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61
Q

Draw a curve representing Guy Lussacs law

A

Benedict Roth spirometer - collecting gas passing through an airway opening. It is an expandable compartment consistent of a moveable statically counterbalanced rigid chamber or bell, a stationary base and a dynamic seal between them. The bell can move up and down freely so pressure inside it is close to atmospheric, the seal is often water but dry seals have been used. Changes in internal volume are proportional to displacement

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62
Q

What is the combined gas law

A
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63
Q

What is the univertsal gas equation

A
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64
Q

Define diffusion

A

Passive movemen tof a substance from an area of high concentration to that of lower concentration

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65
Q

Ficks law of diffusion

A
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66
Q

Add the diffusion constant to Fick’s law of diffusion

A
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67
Q

What factors lead to a faster rate of diffusion

A

Large surface area
Large concentration gradient
Small thickness ot diffuse through
High solubility in medium diffusing thorugh
Low molecular weight or density

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68
Q

Grahams law of diffusion

A

rate at which gasses diffuse are inversely proportional to the square root of their densities

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69
Q

Why is Grahams law of diffusion based on density? How can it be rearranged for molecular mass?

A
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70
Q

When does solubility of a gas matter to diffusion rate?

A

When diffusion is moving from a gas through a membrane into a liquid the rate of diffusion is proportional to soliubility of the gas

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71
Q

What two factors does the diffusion constant involve

A
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72
Q

What is osmotic pressure

A

the pressure required to stop the flow from one side of a semi permeable membrane to another

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73
Q

Henry’s law

A

at a cosntant temperature the amount of gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium wiht that liquid

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74
Q

Define partition coefficient

A

the ratio of conentrations of a substance in two phases of a mixture of two immiscible solvents

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75
Q

Blood gas coefficient- what does this mean and reflect?

A

The ratio fo the concentration of an anaesthetic agent in blood to that in the same volume of gas in contact with that blood at equilibrium

This reflects the solubility of the gas in blood

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76
Q

Oil/gas coefficeint - what does it reflect and why does it matter

A

the ratio of the concentration of an anaeshtetic agent in oil (adipose) to that in the same volume of gas in contact with that oil at equilibrium

this reflects the solubility of the gas in adipose/brain tissues in comparison to blood - it will reflect how easily it crosses the BBB. If the oil:blood coefficient is >1 (or blood:oil <1) then the concentration or amount of gas dissolved in adipose tissue will be higher than that in blood

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77
Q

What characteristics are ideal in an inhaled agent?

A

Low solubility in blood

If highly soluble it transfers quickly from the lungs, but has a lower partial pressure in blood once dissolved therefore staying in solution rather than passing to brian tissue therefore taking longer to work, longer to exit the body.

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78
Q

Raoults law

A

the fall in vapour pressure of a solvent is proportional to the molar concentration of the solute

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79
Q

Mathematics of the Beer-Lambert law

A
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80
Q

Define current

A

the flow of an electric charge - this can be electrons or flow of charged particles e.g. ions

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81
Q

Wire resistance is proportional to?

A

Increases with length
Decreases with cross sectoinal area increases
Conduct better at lower temperatures

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82
Q

What is voltage

A

an informal term for electrical potential difference - this is the amount of energy required to move a unit of charge between two points.

1 volt is if 1 coulomb were to move through a potential differenceof 1 volt it would require 1 joule of energy ; or the electrical potential required to move 1 ampere through 1 ohm resistor

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83
Q

Ohms law

A

the potential difference between two points is the product of the resitance and the current flowing

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84
Q

Draw the Ohm;s law pyramid

A
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85
Q

Kirchoffs first law

A

current in = current out
Or the sum of all currents going in and out is zero

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86
Q

Kirchoffs second law

A

closed loop netowrk the total voltage around the loop is equal tot he sum of all voltage drops within the same loop - this is also equal to zero (as the battery produces the voltage gain)

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87
Q

What is power in electircal terms

A

the rate of electrical energy usage/transferrance per second measured in watts - 1 watt is 1 joule transfered per second

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88
Q

Power in electrical terms =

A

Voltage x current
voltage squared / resistance
Current squared x resistance

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89
Q

Resistance in series calculation

A

the total resistance is greater than the largest reisstors

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90
Q

Resistors in parallel equation

A

the total resisstance is smaller than the smallest resistor

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91
Q

Impedence

A

the resistance to thef low of an alternating current - instead of resistance using in DC

Calculations for power remain the same

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92
Q

What is capacitance

A

a measure of the charge a device can hold measured in Farads

The cpacitance = charge stored in coulombs/ potential difference in volts

Energy stored = 1/2 capacitance x voltage squared

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93
Q

The charge Q in a capacitor is given by what equation

A

Q = C x Vc
C is caacitance
Vc is appplied voltage

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94
Q

How do you calculate distance in the pulse echo principle

A

2d = v x t

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95
Q

What is the equation for natural frequency

A
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96
Q

What is the Windkessel effect and how does it apply to arterial lines?

A

◦ The reflected wave in the upper aorta is more prominent however they merge as you progress down the vascular tree, amplification increases as the vascular tree becomes less compliant and more and more reflection waves accumulate —> windkessel effect as the stored energy

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97
Q

In the simple flow model of dye calculation of cardiac output what equation is used to calculate the rate of dye removal from a tank?

A

rate of dye removal = liquid flow x dye concentration

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98
Q

In the simple flow model of dye dilution cardiac output calculation what is flow rate equal to

A

amount of dye added / area under the graph

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99
Q

What is cardiac output equal to in the circulatory flow model diagram dye dilution technique

A

Amount of dye injected / area under graph

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100
Q

Describe the Fick principle in words where oxygen is the substrate

A
  • Total uptake of oxygen by the body is equal to the product of the cardiac output and the arterial-venous oygen content difference
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101
Q

FICK EQUATION

A
  • CO = VO2/ Ca - Cv
    ◦ Blood flow to an organ = rate of uptake or excretion of a substance / arterio-venous concentration difference
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102
Q

How is VO2 measured in the direct Fick method

A
  • VO2 measurement
    ◦ patients breaths through a spirometer containing a known volume of 100% oxygen and a CO2 absorbed, after a minute the volume of O2 remaining in the spirometer allows the calculation of O2 uptake
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103
Q

What is the Stewart Hamilton equation

A
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104
Q

How is the Fick principle used indirectly?

A
  • Measured of cardiac outptu using the Fick equation but substituting estimated values for the some of the measured variables
  • Estimations
    ◦ Uses age/weight and sex based nomogram to estimate VO2 - especially inaccurate if morbidly obese, paralysed, thyrotoxicosis, burns, sepsis, hypothermia where metabolically not normal patients. Additionally pulmonary O2 consumption can be dramatically increased in pnumonia overestimating cardiac output
    ◦ Mixed venous blood assumed on the basis of normal vlues or estimated from CVC samplws; or from end tidal
    ◦ Arterial oxygen content can be estimated from pulse oximetry
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105
Q

What is the equation for cardiac output when an indicator dye is used?

A
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106
Q

What is the equationf or cardiac output when temperature change is used?

A
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107
Q

How is stroke volume derived from pulse contour analysis? How is it calibrated? What is the calibration factor?

A
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108
Q

What is the doppler equation for measuring velocity? How does velocity relate to flow?

A

◦ V = F (d)c / 2 F(O) cos (theta)
‣ V = velocity of blood in descending aorta
‣ F(d)c = change in frequency of the reflected ultrasound x speed of ultrasound in tissue
‣ F(O) = transmitted ultrasound freqeuncy
◦ Blood flow is then determined by velocity x cross sectional area of the descending aorta (thoracic) estimated from patients height and weight

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109
Q

What is the equation for SVR

A
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110
Q

BSA calculation

A
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111
Q

What is cardiac index? How is it calculated? What are its normal values?

A

Cardiac output / BSA

COmparison between cardiac output of patients of a different size

Normal 2.5 - 4 L/min/metre squared

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112
Q

Define stroke volume

A

the volume of blood pumped out fo the L of the heart during each systolic contraction

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113
Q

How is stroke volume determined using cardiac measurement devices

A

cardiac output / HR –> i.e. average SV over 1 minute

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114
Q

SVI define? Normal values

A

CI / HR x 1000

Indexed for body size

33 - 47 mL/metre squared / beat

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115
Q

SVR calculation and normal values

A

80 x (MAP - CVP) / cardiac output

Normal 800 - 1200 dynes-sec/cm ^ -5

116
Q

SVRI - Define?

A

SVR indxed to body size

80 x (MAP - CVP) / CI

Normal vlue 1970 - 2390 dynes-sec/cm^-5 x metres squared

117
Q

Pulmonary vascular resistance calculation

A

80 x (MPAP - PAWP) / cardiac output

Normal value <250 dynes - sec / cm^ -5

118
Q

Hagen Poiseuille law

A
119
Q

Turbulent flow is proportional to? and inversely proportional to?

A
120
Q

Reynolds number

A
121
Q

What affects flow

A
122
Q

Define absorption

A

movement of drug from site of administration into central compartment

123
Q

Define afterload

A

impedance to ventricular ejection/ventricular wall tension/stress to eject stroke volume (as per
Laplace’s law)

124
Q

What does drug affinity refer to

A

attraction of a drug to a receptor

125
Q

Define anaphylactoid

A

clinical indistinguishable from anaphylaxis, cause by complement/indirect histamine release
from mast cell. Dose dependent

126
Q

Anode

A

negative electrode (donates electrons)

127
Q

Avogadros hypothesis

A

equal volume of gases at same temp and pressure contains equal number of molecules.
(One mole of gas = 6 x1023 molecules occupies 22.4L at STP)

128
Q

Bainbridge reflex

A

increased intravascular volume in normovolemic pts causes reflex tachycardia independent
of increased blood pressure

129
Q

Baricity

A

density of liquid in relation with CSF

130
Q

Basal metabolic rater

A

minimal metabolic rate, amount of energy liberated per unit time to maintain basal
cellular function (J/s or W) at defined conditions (rest, room temperature, 12hr post-meal)

131
Q

Define base excess

A

blood sample equilibrated to PaCO2 40mmHg (titrated with acid/base until pH is normal)

132
Q

beer lamert law

A

intensity of light passing through a solution decreases exponentially with concentration
(Beers) and distance (Lambert)
I Trans = I Incident.e-A A=absorption (A= distance x extinction coefficient x concentration)

133
Q

Define bernoulli effect

A

decreased pressure in tube as velocity of flow increases

134
Q

Define bioavailability

A

proportion of drug which reaches systemic circulation FB=FA x (1-HER)

135
Q

Blood volume distribution in veins

A

65%
55% if supine

136
Q

% of blood in arteries at any one time

A

13%

137
Q

% of blood in capillaries at baseline

A

5%

138
Q

% of blood in arterioles at baseline

A

2%

139
Q

% of blood centrally aat baseline?

A

15%
25% when supine (the only source from which veinous redistribution goes to)

140
Q

Blood gas partition coefficient

A

Blood Gas Partition Coefficient – ratio of anaesthetic agent in equilibrium at 37oC contain same partial pressure
between the 2 phases

141
Q

Bohr effect

A

Bohr Effect – the variable affinity of Hb to O2 in the variable concentration of H+ and PCO2

142
Q

Bohr equation

A

amount of physiological dead space in lung Vd/Vt=PaCO2 – PeCO2/PaCO2

143
Q

Bourdon gauage

A

coiled metal where a rise in temperature cause the tube to uncoil

144
Q

Define buffer

A

substance which to receive or donate H+ in solution preventing the change in pH

145
Q

Calorie

A

heat energy necessary to raise the temp of 1g of H2O by 1oC

146
Q

% of blood flow to heart? % of VO2?

A

5% - 70% LCA
10% of VO2

147
Q

Renal % of blood flow? % of VO2?

A

25% of blood flow
90% of which goes to cortex, 5% medulla

7% of VO2

148
Q

Brain blood flow? O2 extraction?

A

15% of CO
65% grey matter

20% VO2

149
Q

L:iver blood flow? VO2?

A

25-30% CO
1/3 hepatic artery

25% VO2

150
Q

Skeletal muscle cardiac output? VO2

A

20% for both

151
Q

What is bathmotropy?

A

Bathmotropy: excitability, ease of myocyte depolarise by stimulus (slope phase 0)

152
Q

Cardaic properties?

A

Automaticity: ability to initiate own beat
Dromotropy: speed of conduction via AV node
Inotropy: contractility
Lusitropy: active relaxation
Bathmotropy: excitability, ease of myocyte depolarise by stimulus (slope phase 0)
Irritability: size of stimulus required to depolarise cell in context to resting phase
(difference between threshold and RMP

153
Q

Cathode

A

Cathode – positive electrode which receives electron

154
Q

Define chiral

A

Chiral – asymmetric in which the structure and its mirror image is not superimposable

155
Q

Clearance

A

volume of plasma clear of a drug per unit time

156
Q

Closing capacity

A

the lung volume at which dependant airways begin to close (CV+RV)

157
Q

Colligative properties

A

properties of a solution that depends only on the number of freely moving particles and
not on the nature of those particles
i.e. – Osmotic pressure, Boiling point elevation, Freezing point depression, Vapour pressure depression

158
Q

Colloid

A

substances unable to pass semipermeable membrane (suspension of solutes)

159
Q

Compliance

A

change in volume over change in pressure. (Normal 200ml/cmH2O) affected by lung elastic
recoil/lung volume/disease/pulmonary blood volume

160
Q

Static compliance

A

patient inspiring sequentially to different known volume, relaxing against a closed
glottis (time for equilibrium to occur) =VT/(Pplateau-PEEP)

161
Q

Dyanamic compliance

A

against normal breathing, volume and pressure at point of no flow =VT/(Ppeak-
PEEP)

162
Q

Specific compliance

A

compliance divided by FRC (Normal: 0.05/cmH2O)

163
Q

Context sensitive half time

A

time for plasma concentration of a drug to decrease by 50% after stopping the
infusion designed to maintain steady state
Dependant on: Duration of infusion/Distribution/Clearance

164
Q

Define contractility

A

Contractility – myocardial performance factor that is independent of heart rate and loading factors

164
Q

Define convection

A

mode of heat transfer via bulk movement of liquid or gas in contact

165
Q

Coronary perfusion pressure

A

Diastolic BP-LVEDP

166
Q

Counter current exchange

A

provides circulatory perfusion to LOH and CD while maintaining hypertonic
interstitial medullary gradient

167
Q

Counter current multiplier

A

concentrating effect of the medullary interstitium multiplied by the counter
current flow of tubular fluid within LOH

168
Q

Critical pressure

A

pressure required to liquefy a vapour at its critical temperature

169
Q

Critical temperaturw

A

temperature above which substance cannot be liquefied however much pressure applied

170
Q

Critical velocity

A

velocity above which laminar flow become turbulent

171
Q

Major cross match

A

part of blood compatibility testing (to prevent haemolysis post transfusion)
Major – patient serum + donors’ RBC
Saline agglutination: reconfirms ABO grouping
Indirect Coombs: reconfirms presence of minor antibodies

172
Q

Minor cross match

A

Minor – patient RBC + donors’ serum

173
Q

Define crystalloid

A

substances able to pass semipermeable membrane

174
Q

Daltons law

A

the pressure exerted by a mixture of gas = the sum of pressures of each individual gasses

175
Q

Damping?

A

resistance to free oscillation
Under damping: overshoot common, system oscillates
Over damping: slow signal response with inability to respond to rapid change
Critical damping: point of overshoot is just avoided
Optimal damping: 64% critical damping, minimal overshoot and minimal response reduction

176
Q

Under damping

A

resistance to free oscillation
Under damping: overshoot common, system oscillates
Over damping: slow signal response with inability to respond to rapid change
Critical damping: point of overshoot is just avoided
Optimal damping: 64% critical damping, minimal overshoot and minimal response reduction

177
Q

Overdamping

A

resistance to free oscillation
Under damping: overshoot common, system oscillates
Over damping: slow signal response with inability to respond to rapid change
Critical damping: point of overshoot is just avoided
Optimal damping: 64% critical damping, minimal overshoot and minimal response reduction

178
Q

Critical damping

A

resistance to free oscillation
Under damping: overshoot common, system oscillates
Over damping: slow signal response with inability to respond to rapid change
Critical damping: point of overshoot is just avoided
Optimal damping: 64% critical damping, minimal overshoot and minimal response reduction

179
Q

Optimal damping

A

resistance to free oscillation
Under damping: overshoot common, system oscillates
Over damping: slow signal response with inability to respond to rapid change
Critical damping: point of overshoot is just avoided
Optimal damping: 64% critical damping, minimal overshoot and minimal response reduction

180
Q

Dead space and its components

A

tidal volume that does not take part in ventilation
Physiological – alveolar + anatomical (Bohr’s equation)
Anatomical – volume of conducting airways (Fowler’s method)
Alveolar – volume beyond conducting airways that do not take part in ventilation (V/Q mismatch)

181
Q

Decontamination

A

process which removes/destroys contaminants

182
Q

Cleaning

A

physical removal of foreign material

183
Q

Disinfection

A

process of eliminating most pathogenic organism except spores

184
Q

Disinfectant

A

chemical used to disinfect non-living surfaces

185
Q

Antiseptic

A

chemical used to disinfect living surfaces

186
Q

Sterilisation

A

process of killing all microbes

187
Q

Dependence

A

psychophysical requirement of continued supply of substance
Physical dependence: characterised by withdrawal symptoms after discontinuation of a drug or after
administration of an antagonist
Psychological dependence: a chronic state, characterised by the compulsive use of a substance resulting
in harm (physical, psychological or social) and continued use despite harm

188
Q

What are 2 examples of desensitisation

A

Tachyphylaxis: acute decrease in response to repeated dose of a drug
Tolerance: chronic decrease in response to repeated dose of a drug

189
Q

Tachyphylaxis

A

Tachyphylaxis: acute decrease in response to repeated dose of a drug
Tolerance: chronic decrease in response to repeated dose of a drug

190
Q

Tolerance

A

Tachyphylaxis: acute decrease in response to repeated dose of a drug
Tolerance: chronic decrease in response to repeated dose of a drug

191
Q

Dibucaine number

A

% inhibition of plasma cholinesterase activity after addition of dibucaine (quality of plasma
cholinesterase)

192
Q

Diffusion

A

movement of substances down its concentration gradient (obeys Fick’s law of diffusion)

193
Q

Diffusion hypoxia

A

reduced alveolar O2 concentration from dilution by N20 leaving the blood stream and
entering the alveoli

194
Q

Doppler effect

A

frequency shift effect where the frequency and wavelength of a signal changes in relation to
changes in soundwaves when source moves in relation to stationary observer

195
Q

ECG

A

graphical presentation of surface recording of electrical activity of heart

196
Q

EEG

A

graphical presentation of surface recording of electrical activity of neural cells (specifically the postsynaptic
potentials of subcortical neurons perpendicular to electrode)

197
Q

Efficacy

A

maximal effect attainable by drug

198
Q

Elimination

A

amount of drug excreted by the body

199
Q

Emulsion

A

pair of immiscible fluid (droplet disperse throughout another) inherently unstable and tend to coalesce
so need emulsifier to improve solubility

200
Q

Enzyme

A

biological catalyst

201
Q

Eutectic

A

mixture in which the physicochemical properties are different to that of its individual component

202
Q

Evaporation

A

mode of heat transfer via vaporisation of H2O from surface

203
Q

Fick prinicple

A

blood flow to an organ equals rate of substrate uptake/removal divided by A-V concentration
difference for that substance

204
Q

Laminar flow

A

Laminar: organised, parabolic, flow proportional to pressure
Turbulent: disorganised, eddies, flow2 proportional to pressure

205
Q

Turbulent flow

A

Laminar: organised, parabolic, flow proportional to pressure
Turbulent: disorganised, eddies, flow2 proportional to pressure

206
Q

Fouriers analysis

A

construction of complex waveform from multiple basic sine waves of different frequency
Slowest component: fundamental frequency
Faster component: harmonics

207
Q

Define FRC

A

lung volume at the end of normal tidal expiration, equilibrium point where the
chest wall expand outwards and the lung collapsing

208
Q

Boyles law

A

Boyle’s Law (1st gas law): at a constant temperature, volume of gas is inversely proportional with
absolute pressure (PV=k, T constant)

209
Q

Charles law

A

Charles’ Law (2nd gas law): at a constant pressure, volume of gas is directly proportional to absolute
temperature (V~T, P constant

210
Q

Amontons law

A

Amonton’s Law (3rd gas law): at a constant volume, pressure is directly proportional to temperature (P~T,
V constant)

211
Q

Daltons law

A

Dalton’s Law: the pressure exerted by a mixture of gas = the sum of pressures of each individual gasses

212
Q

Henry’s law

A

Henry’s Law: at given temperature, amount of a given gas dissolved in a given liquid is directly
proportional to the partial pressure of the gas in equilibrium with the liquid
Poynting effect: formation of a gaseous mixture of O2 and N2O when O2 is bubbled

213
Q

Gibbs Donnan

A

distribution of charged diffusible ions in the presence of non-diffusible ions across a
semi-permeable membrane
Responsible for: Oncotic pressure
Cell volume stability (double Donnan)
RMP

214
Q

Define haldane effect

A

Deoxygenated Hb has increased ability to carry CO2

215
Q

Define half life

A

the time necessary for drug concentration to decrease by 50%

216
Q

Haemostasis

A

physiological process of maintaining blood in a fluid clot free-state in normal vessel or producing
rapid localised coagulation at site of injured vessel

217
Q

Evaporation

A

Evaporation – via vaporisation of water (0.56kcal energy for 1g H2O

218
Q

Heat capacity

A

amount of heat required to raise the temperature of a given object by 1 Kelvin

219
Q

Hormones

A

chemical messenger produced by ductless glands and transported to act on distant target sites via
circulation in trace amount

Peptides
Amines
Steriods

220
Q

Peptide examples

A

Peptides – glucagon, insulin, PTH, ACTH, LH, FSH
Amines – derived from tyramine (T3/T4, NAdr, Adr) or tryptophan (5HT, Melatonin)
Steroids – synthesised from cholesterol (androgens, sex hormones, vit D)

221
Q

Amines examples

A

Peptides – glucagon, insulin, PTH, ACTH, LH, FSH
Amines – derived from tyramine (T3/T4, NAdr, Adr) or tryptophan (5HT, Melatonin)
Steroids – synthesised from cholesterol (androgens, sex hormones, vit D)

222
Q

Steriods examples

A

Peptides – glucagon, insulin, PTH, ACTH, LH, FSH
Amines – derived from tyramine (T3/T4, NAdr, Adr) or tryptophan (5HT, Melatonin)
Steroids – synthesised from cholesterol (androgens, sex hormones, vit D)

223
Q

Huffners number

A

1.34 is amount of oxygen which can combine with 1g of Hb when fully saturated

224
Q

Absolute humidity

A

Absolute: mass of H2O in a given volume of air (mg/L)
Relative: ratio of mass of H2O vapour in a given volume of air to the mass required to saturate
the volume at the same temperature

225
Q

Relative humidity

A

Absolute: mass of H2O in a given volume of air (mg/L)
Relative: ratio of mass of H2O vapour in a given volume of air to the mass required to saturate
the volume at the same temperature

226
Q

Interthreshold range

A

range of body temperature where ANS is not triggered

227
Q

Innate immunity components

A

Innate immunity: Humoral – complement system
Cellular – macrophages, neutrophils, barrier

228
Q

Acquired immunity components

A

Acquired immunity: Humoral – B-cell, immunoglobulins
Cellular – T-cell mediated

229
Q

Define isomer

A

compounds with the same molecular weight but different structural or spatial arrangement

230
Q

Types of isomers

A

Structural
Stereoisomers

231
Q

Structural isomer types

A

Structural isomers: positional/tautomers

232
Q

Types of stereoisomers

A

Stereoisomers: enantiomers/diastereomers/geometric isomers

233
Q

Latent heat

A

heat required to convert 1kg of a substance from one phase to another at a given temperature

234
Q

Manometers measure?

A

Manometer – decide to measure pressure of gas

235
Q

MAP =

A

Mean Arterial Pressure (MAP) – the product of CO x SVR
=DBP+1/3(SBP-DBP)

236
Q

Monro Kellie doctrine

A

Monro-Kellie Doctrine – the cranium is a rigid closed vault. Total volume is fixed, any increase in intracranial
content will result in large increase in pressure (blood/brain/CSF)

237
Q

Muscle spindle

A

Muscle Spindle – intrafusal muscle fibre (10 in a capsule) which are concerned with proprioception

238
Q

Define osmotic pressure

A

Osmotic Pressure – minimum pressure necessary to prevent the movement of solvent

239
Q

Osmosis

A

Osmosis – diffusion of solvent (H2O) down its concentration gradient

240
Q

Osmolality

A

Osmolality – number of osmole per kg of solute non dependant on temperature

241
Q

Osmolarity

A

Osmolality – number of osmole per kg of solute non dependant on temperature

242
Q

Osmolarity

A

Osmolarity – number of osmole per litre of solvent dependant on temperature

243
Q

p50

A

P50 – PO2 at which Hb is 50% saturated. Relates to Hb affinity

26.6 for HbA

244
Q

pKa

A

pKa – negative log of acid dissociation constant (Ka), where Ka = (H+) (A-)/ (HA), buffering capacity of the buff
(pKa +/- 1 for closed system) or degree of ionisation (50% @pH=pKa)

245
Q

Primary hyperalgesia

A

Primary hyperalgesia – peripheral sensitisation, stimulus at site produces more pain
Secondary hyperalgesia – central sensitisation, increased responsiveness in surrounding site

246
Q

Secondary hyperalgesia

A

Primary hyperalgesia – peripheral sensitisation, stimulus at site produces more pain
Secondary hyperalgesia – central sensitisation, increased responsiveness in surrounding site

247
Q

Allodynia

A

previously non-painful stimulus now painful

248
Q

Wind up in the context of pain

A

central sensitisation to pain which impulse strengthens with repetitive stimulation (includes
long term potentiation)

249
Q

Partition coefficient

A

ratio of concentration of substance in 2 phases in equilibrium (equal volume and pressure)
at stated temperature (normally 37oC), related to solubility of substances in different phases
BGPC (blood: gas) inversely proportional to speed of onset/offset
OGPC (oil: gas) proportional to potency and metabolism
TGPC (tissue: gas) proportional to tissue uptake/offset

250
Q

Piezoelectric

A

ability to interconvert between mechanical energy and electrical energy

251
Q

Post tetanic count

A

number of responses to 1Hz stimulation for 3 seconds after 5sec of 50Hz tetanus
PTC 8-10: first TOF
PTC 0: no buck or cough

252
Q

potency

A

Potency – drug dose required to achieve certain response, related to receptor affinity (PD) and PK

253
Q

Define preload

A

Isolated: initial fibre length prior to contraction = amount of stretch of ventricular muscle fibre at the end
of ventricular filling
Intact: compliance x transmural pressure (filling pressure – extrinsic pressure)

254
Q

Pressure

A

force per unit area (Pascal or N/m2)
Gauge Pressure – pressure above/below atmospheric pressure
Absolute Pressure – gauge + atmospheric pressure

255
Q

Reduction

A

removal of O2 or gaining e-

256
Q

Residual volume

A

volume of gas in the lings at end of maximal expiration

257
Q

Resonance

A

tendency at which system oscillates at greater amplitude at certain frequency

258
Q

Respiratory quotient? How and why does it vary?

A

the ratio in steady state of volume of CO2 produced per volume of O2 consumed per
unit time (Carbohydrate: 1, Protein: 0.8, Fat: 0.7)

259
Q

Reynolds number equation

A

Re = PʋD/η turbulent if Re >2000

260
Q

Sarcomere

A

contractile unit of a myofibril separated on each ends by Z lines

261
Q

Saturated vapour pressure

A

the pressure of a vapour which is in equilibrium with its liquid phase, indicator of
volatility

262
Q

Second gas effect

A

uptake of large volume of primary gas accelerates the rate of rise of second gas given
concurrently

263
Q

Shunt

A

blood entering the arterial system without passing through ventilated lung

264
Q

Causes of shunt

A

Physiological Shunt:
True Shunt: Thebesian veins & bronchial arteries
Others: V/Q mismatch (V/Q ratio <1)
Pathological Shunt: patent foramen ovale, atelectasis, pneumonia

265
Q

Macro and micro shock

A

Macroshock: current >10mA or current passes through the trunk/heart in electrocution
Microshock: low current passes through cardiac muscles sufficient to cause cardiac arrhythmias

266
Q

Sleep

A

physiological decrease level of consciousness and awareness but easily rousable

267
Q

Specific heat capacity

A

amount of heat required to raise the temperature of 1kg of a substance by 1 Kelvin

268
Q

Starlings law of the heart

A

Starling’s Law of the Heart – the force of contraction is dependent on the end-diastolic muscle fibre length

269
Q

Temperature

A

thermal state of a substance which determines whether it will give heat to another substance or
receive heat (unit SI – Kelvin)

270
Q

Therapeutic index

A

ratio of drug dose causing adverse effect over dose causing desirable effect (LD50/ED50)

271
Q

Thermoneutral zone

A

range of ambient temperature at which VO2 (metabolic rate) is at minimum
(thermoregulation can occur via changes to skin blood flow alone)
Adult: 25-30oC
Term: 32-34oC
Prem: 34-36oC

272
Q

Time constant

A

the time it would take for an exponential process to be completed should the initial rate of
change remains the same 1τ: 63% completed

273
Q

Tonicity

A

effective osmolality of a solution

274
Q

Tubuloglomerular feedback

A

renal autoregulation to ensure constant GFR (via detection of Na/Cl by macula
densa)

275
Q

Ultrafiltration

A

process which water is removed from blood during various forms of dialysis. Water passing
through a semi-permeable membrane as a result of positive pressure on the blood side of membrane

276
Q

Valsalva manouvre

A

forced expiration against a closed glottis (standardised, forced expiration against a closed
glottis for 10-15secs at 40mmHg)

277
Q

Vapour

A

substance in gaseous phase below its critical temperature

278
Q

Vapour pressure

A

pressure exerted by molecules in vapour phase

279
Q

Viscocity

A

property of liquid which creates resistance/impendence to free flow, given by shear stress/shear rate

280
Q

Vital capacity

A

maximum volume of gas that can be exhaled following maximum inspiration

281
Q

Vitamin

A

organic substance, not produced in the body, small amount essential for life, for biochemical reactions
(non-energy substrate)

282
Q

Volume of distribution

A

apparent volume in which a given amount of substance must be dispersed to give the
resultant plasma concentration

283
Q

Wheatstone bridge

A

often incorporated as part of a transducer circuit to amplify signals, composed of a set of
four resistors in series, an electrical source and a galvanometer, with one of the resistors often part of a strain
gauge or resistance thermometer

284
Q

Work of breathing

A

Force (N) x Distance (m) = Pressure x Volume
Elastic Resistance 60% (Surface Tension 70%; Elastic Tissue 30%)
Non Elastic Resistance 40%

285
Q

Windkessel effect

A

hydraulic effect of large elastic arteries which converts the intermittent output of heart to a
steady flow through capillaries (maintain perfusion of organ during diastole when cardiac ejection cease)

286
Q
A

Misc - temp/procedures (7 decks)

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