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83 Cards in this Set
- Front
- Back
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What is force?
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That which changes of tends to change the state of rest or motion of an object
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What is the formula for force?
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F=M x A
Force equals mass times acceleration |
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What is a newton?
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A force which accelerates a mass of 1 kg at a rate of 1 meter per second per second
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What is the force of gravity acting on an object to give it acceleration?
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9.81 N
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What is a pascal?
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1 pascal is a pressure of 1 newton acting over an area of 1 sq meter. 1Pa=1N/1m^2
also called a bar of pressure |
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What is the gram weight of a newton?
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102 grams
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What is inertia?
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A resistance of any physical object to change.
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What is mass?
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-a numerical measure of inertia
-the amount of matter that makes up an object *Mass and inertia are directly related; the more mass an object has the more resistant to change |
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What counteracts inertia on Earth?
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Gravity
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What is momentum?
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Movement of an object related to its mass and velocity
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What is velocity? (m/s)
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The measure of the rate and direction of change in the position of an object
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What is acceleration? (m/s^2)
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The rate of change of velocity over time
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What is pressure?
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The force applied of distributed over a surface and is expressed as force per unit area.
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How much pressure is given during cricoid pressure?
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20-30 N or 6lbs of pressure
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Where is cricoid pressure applied?
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Over the 6th vertebrae
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What is weight?
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A pull of gravity, measured on a scale, changes with location
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What does 1 atom equal?
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- 101.3 kPa
- 14.696 psi - 1.01325 Bar - 760 mmHg Torr -1033 cm H2O |
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Types of gauges that measure pressure
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Manometer
Barometer Vacuum Gauges |
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What does a manometer measure?
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-Liquid colum hydrostatic instrument
-Measures pressures near atmospheric |
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What does a barometer measure?
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-Instrument used to mearure atmospheric pressure
-Uses water, air, mercury |
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What kinds of vacuum gauges are there?
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High & Low
-Aneroid -Bourdon |
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What are newton's three laws of motion?
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1. All matter has inertia
2. Force equals mass times acceleration 3. For every action there is an equal and opposite reaction |
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What is gravitational force?
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Acceleration due to gravity.
9.80 m/sec^2 |
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Force of gravity
Fg=force of gravity G=The gravitational constant m1 & m2= The masses of the two particles r=The straight line distance between the two particles |
Fg= G x m1 m2/r2
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Formula for acceleration
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a=F/m
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What is the formula for pressure?
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P=Force/Area
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What is scalar?
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Pressure, distance, mass, height, age.
It has magnitude but no direction |
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What is vector?
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Velocity
It has magnitude and direction |
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Manometer math
-Force exerted by column of mercury F=m x a (due to gravity) so F=m x g Pressure exerted is P=F/A so P=m x g/A Density is mass over volume d=m/V therefore m=d x V Manometer equation P=d x V x g/A |
P=d x V x g/A
For a column Volume is area times height V=A x h So equation becomes P=d x A x h x g/A Cross sectional area cancels out P=d x h x g |
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What is absolute pressure?
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Atmospheric pressure plus pressure measured
P (absolute) = Pg + Po Pg=gauge pressure Po=atmospheric pressure |
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Whart is gauge pressure?
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Measured relative to atmospheric pressure
Referenced kPa (gauge) or psig |
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A tire is inflated to 32 psig, what is the gauge pressure?
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32psi + 14.7 psi (atm) = 46.7 psi
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What is work?
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Work is done or energy expended whenever the point of application of force moves in the direction of force.
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When is 1 joule of work completed?
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When a force of one newton moves to the point of application on meter in the direction of the force.
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What is the formula of work done?
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Work=F*D or for liquid P*V
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What is power?
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Power is the rate of working and is measured in watts.
1 watt is 1 joule per second Electricity=power |
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What is the power equation?
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W=J s -1
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What is kinetic energy?
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Energy in motion and performing work.
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What is potential energy?
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Energy that exists secondary to its position in relation to other energy sources but does not cause work to be done.
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What is energy?
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The ability to do work
-It cannot be created or destroyed -The amount of energy transferred per unit of time. |
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What is a non-newtonian fluid?
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- Viscosity changes with respect to shearing force.
-Not constant/ have both liquid and solid properties, depending on the shearing force. -Oobleck |
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What is hydrostatic pressure?
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Fluid that is not moving
-characterized by pressure and density |
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What is hydrodynamics?
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Fluids in motion
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What are the two important properties of static fluids?
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Density and depth
- It is independent of the width or shape of the fluid column. -Does not depend on the shape, total mass, or surface area of the liquid. |
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What is the formula for pressure?
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P=h x d x g
pressure equals the height multiplied by density multiplied by gravity. |
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Where would you place your transducer for a sitting craniotomy?
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External auditory canal.
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What is Archimedes principle on buoyancy?
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An object immersed either totally or partially in a fluid feels a buoyant force equal to the weight of fluid displaced.
-the deeper it goes, the more pressure is applied. |
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What do hydrometers do?
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measure density of liquids
weighted and calibrated sinks until displaces an amount of fluid exactly equal to its weight In dense fluid hydrometer displaces small amount of fluid-does not sink deep In less dense fluid, hydrometer displaces a large amount of fluid and sinks. |
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What is Pascal's principle?
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Force is transmitted undiminished in enclosed static fluid. Ex: hydrolyic lift or retinal tear.
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What is the law of Laplace for cylinders?
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The greater the internal pressure, or the larger the radius, the greater the wall tension.
T=P x R |
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What is the formula for the Law of Laplace in spheres?
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T= (P x R)/2
P= 2(T/R) |
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What is surface tension?
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The force acting on the surface of a liquid, tending to minimize the area of a surface.
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How does the law of Laplace relate to healthy aveoli?
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Surfactant
-reduces surface tension -makes existing surface tension variable depending on the radius of the alveoli. Larger alveoli has more pressure and air goes to smaller aveoli. |
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How does the law of Laplace relate to unhealthy aveoli?
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Without surfactant
-increased surface tension at any given radius -pressure is more dependent on radius Smaller aveoli has more pressure and air goes to larger aveoli. |
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What is flow?
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The quantity of fluid passing a point per unit of time.
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What is laminar flow?
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Smooth and steady, w/o eddies or turbulence
-fluid at the center will have greater velocity than the sides. -exerts little resistance -increase pressure gradient, increase fluid flow |
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What is Poiseuille's law?
Q=Pttr64/nl |
Fluid flow is proportional to:
-pressure gradient -radius Fluid flow is inversely proportional to: -Viscosity -Length |
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What is the most determinent factor for laminar flow?
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Radius
-halving the radius reduces the flow by 1/16th of its original value |
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What does the Bernouli Principle state?
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Pressure of a fluid decreases as its velocity increases.
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What is turbulent flow?
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Chaotic, swirls and eddies in flow.
-flow is no longer determined by pressure Contributors: high flow velocities large diameter tubes high fluid density low viscosities bends, curves partial obstructions irregular shapes |
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What is the Reynold's number?
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It quantifies the onset of turbulent flow.
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What is the Reynold's number to determine turbulent flow?
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2000
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What is the relationship between pressure and turbulent flow?
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Curviliner relationship
-greater increase in pressure for every increase in flow. |
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What is the most important factor for turbulent flow?
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Density
-increased density=increased turbulence and vice versa. -not related to viscosity |
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What kind of relationship does viscosity and turbulent flow have?
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Inverse
-high viscosity=decreased rate/likelihood of onset of turbulent flow and vice versa |
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What is solubility?
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The amount of solute that will dissolve in a given amount of solvent at a given temperature.
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What is a saturated solution?
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Contains the maximum amount of solute, as defined by its solubility.
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What is a supersaturated solution?
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Contains more solute than allowed by the solubility of the solute; unstable. Ex: Kidney stones
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What is Henry's law?
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the solubility of a gas in a liquid at a particular temperature is proportional to the pressure of that gas above the liquid.
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What are examples of Henry's law?
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Opening a can of pop, decompression sickness, high altitute breathing.
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Variables that affect solubility
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Partial pressure
Temperature Type of gas Type of liquid |
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What is the Bunsen Solubility Coefficient?
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Used by scientists
Volume of gas which dissolves n 1 unit volume of a liquid (0 degree celcius + 1 Atom) |
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What is the Ostwald Solubility Coefficient?
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Volume of gas which dissoves in 1 unit volume of liquid at a specified temp.
-independent of pressure -utilized by anesthetists....not as much in U.S. |
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What is a partition coefficient?
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Ratio of the amount of substance present in one phase compared with another, the two phases being of equal volume and equalibrium.
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What are the types of partition coefficients?
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Blood:Gas
Tissue:Gas Tissue:Blood Oil:Water Oil:Gas Fat:Blood OIL = FAT |
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What does the blood/gas coefficent determine?
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The onset and offset of action
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What does an oil/gas coefficient measure?
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The potency of a substance. The more "oil" the more potent
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What is MAC?
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Minimum Aveoli Concentration that prevents movement in 50% of patients.
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What is diffusion?
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An attempt to achieve equalilibrum.
Goes from high conc to low conc Liquids are slower than gases Physical barriers -membranes -cell membranes Gas/liquid interfaces -alveolus |
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What factors affect the rate of diffusion?
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Concentration gradient
Surface area Solubility Inverse effect: membrane thickness molecular weight |
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What is Fick's law of diffusion?
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The rate of diffusion of a substance is directly proportional to the concentration gradient.
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What is a concentration gradient?
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a measurement of how the concentration of something changes from one place to another.
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Increased gradient=Increased diffusion rate
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Decrease gradient=decreased diffusion rate
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