RT 21Exam 1 Review

According to the law of conservation of energy, energy cannot be created or

destroyed: energy can only be transferred.

All matter is comprised of molecules that are in constant motion. The degree of this motion differs among three states of matter (solid, liquid and gas) and their intermolecular forces

Kinetic TheoryStates that the atoms & molecules that

make up matter are in constant motion.Temperature influences movement of

molecules. Hot objects move more than cold objects. Increasing kinetic energy increases temperature

Thermal energy = molecular Kinetic Energy + Potential Energy

The 3 states of matter

http://www.youtube.com/watch?v=guoU_cuR8EE

Solids – have a high degree of internal order; their atoms have a strong mutual attractive force

Liquids – atoms exhibit less degree of mutual attraction compared with solids, they take the shape of their container, are difficult to compress, exhibit the phenomenon of flow

Gases – weak molecular attractive forces; gas molecules exhibit rapid, random motion with frequent collisions, gases are easily compressible, expand to fill their container, exhibit the phenomenon of flow

States of Matter

States of Matter

Internal energy of matter

•Potential energy (Position) The strong attractive forces between molecules that cause rigidity in solids

•Kinetic energy (Motion) Gases have weak attractive forces that allow the molecules to move about more freely, interacting with other objects that they come in contact with

Internal energy and temperature

•The two are closely related: internal energy can be increased by heating or by performing work on it.

•Absolute zero = no kinetic energy

All matter possesses energy. There are 2 types of internal energy:The energy of position, and the energy of motion.

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Change of State

Liquid-solid phase changes (melting and freezing)

Melting = changeover from the solid to the liquid state

Melting point = the temperature at which melting occur.

Freezing = the opposite of melting

Freezing point = the temperature at which the substance freezes; same as its melting point

• Temperature: the amount of heat energy in matter expressed in terms of a specific scale

• Three common scales of temperature:

– Celsius (used in health care)• Body temperature 37 degrees C (+/-1) • Boiling point of water 100 degrees C• Freezing point of water 0 degrees C• Absolute 0 (no molecular movement) -273 C

– Fahrenheit (common US household scale)• Body temperature 98.6 degrees (+/- 1)• Boiling point of water 212 degrees F• Freezing point of water 32 degrees F• Absolute 0 (no molecular movement) -280 F

– Kelvin (used in research)• Absolute 0 (no molecular movement) 0 Kelvin

Temperature

Temperature• Absolute Temperature Scale: A temperature measurement scale in which

the 0 point is absolute 0 or the temperature at which all molecular motion ceases. Absolute 0 temperature is about -273 Celsius. The absolute temperature scale for Celsius is called the Kelvin temperature scale. Celsius temperatures can be converted to Kelvin temperatures by adding 273 degrees to the Celsius temperature as shown below:

• Kelvins = Celsius + 273 Example: Convert 37 C to Kelvins

• Kelvins = 37 + 273 = 310 KelvinsTo convert Kelvin temperatures to Celsius, subtract 273 as shown below:

• Celsius = Kelvins - 273• Example: Convert 298 Kelvins to Celsius• Celsius = 298 K - 273 = 25 Celsius

To convert Fahrenheit to Celsius, use the following formula:

C = .55 x (F - 32)Example: Convert 60 Fahrenheit to CelsiusC = .55 (60 - 32) = .55 x 28 = 15 Celsius

To convert Celsius to Fahrenheit, use the following formula:

F = (1.8 x C) + 32Example: Convert 20 Celsius to FahrenheitF = (1.8 x 20) +32 = 36 + 32 = 68 Fahrenheit

Temperature Conversion

• Pressure: A measurement of force per unit area, ie: pounds per square inch (PSI)

• Absolute Pressure Scale: A pressure scale in which the 0 point is a complete vacuum or the pressure at which all molecular motion ceases. Absolute pressure includes atmospheric pressure.

• Gauge Pressure Scale: A pressure scale in which the 0 point is atmospheric pressure or the pressure of the atmosphere pushing down on a given point on the earth.

Pressure

Critical temperature: o The temperature reached in which gaseous

molecules cannot be converted back to a liquid, no matter what pressure is exerted on them.

o The highest temperature at which a substance can exist in a liquid state.

Critical pressure:

o The critical pressure of a substance is the pressure required to liquefy a gas at its critical temperature.

Critical Temperature and Pressure

Atoms

• An atom is classified according to the number of protons and neutrons in its nucleus: the number of protons determines the chemical element, and the number of neutrons determines the isotope of the element

Atomic Particles

• subatomic particles are particles smaller than atoms

• Basic structures include protons, neutrons and electrons

Neutron

• Neutron is also in the atoms nucleus• It is a subatomic particle with no electric

charge and a mass of 1 amu• The sum of the neutrons inside the nucleus

he number of the protons = atomic mass • Most atoms of elements can accommodate

additional neutrons in their nucleus – Ex: Oxygen, three variations with varying atomic

mass

Electron

• Electron is the lightest subatomic particle. It is a negatively charged particle.

• Its mass is only 1/1,840 the mass of a proton. An electron is therefore considered to be mass-less in comparison with proton and neutron and is not included in calculating atomic mass of an atom.. Under ordinary conditions, electrons are bound to the positively charged nucleus by the attraction created from opposite electric charges.

• An atom may have more or fewer electrons than the positive charge of its nucleus and thus be negatively or positively charged as a whole; a charged atom is called ion. In plasma, electrons exist in free state along with ions.

What is the difference between a compound and a molecule?

• A molecule is formed when two or more atoms join together chemically.

• A compound is a molecule that contains at least two different elements. All compounds are molecules but not all molecules are compounds.

• Molecular hydrogen (H2), molecular oxygen (O2) and molecular nitrogen (N2) are not compounds because each is composed of a single element.

• Water (H2O), carbon dioxide (CO2) and methane (CH4) are compounds because each is made from more than one element.

Chemical Bonding (type I)• Electrovalent (Ionic) Bonding

– Two or more elements combine with each other by transferring electrons

– One electron leaves outermost electron shell of one atom and enters outermost shell of other atom

– Tendency in nature is for all atoms to seek eight electrons in their outermost electron shell (RULE OF EIGHT)

– Ex: Na and Cl, Cl has 7 electrons in its outermost shell and Na has one. When the two elements react NA transfers its lone electron to Cl making Cl negatively charged, and sodium becomes positively charged since it lost an electron. Creating ions of Na and Cl

– The bond that holds Na and Cl together is called electrovalent– The electrostatic attraction between these opposite charges

maintains molecular integrity (NaCl)

Chemical Bonding (type II)• Covalent Bonding

– Results from the sharing of one or more pairs of electrons to form covalent molecules

– Example: two Oxygen Molecules– Oxygen has two unpaired electrons in its

outermost shell (total of 6), this combines with two from another Oxygen molecule to form O2

Chemical Bonding• Some compounds are held together from a combination of both

types of bonds • As elements react to form compounds, electrons are either

shared or transferred or both• The electrons involved in these processes are called valence

electrons• The valence of an atom is the number of electrons transferred

(donated or received) in forming ions• Ex: Na has a valence of 1 because it donates one electron and

forms the Na+ cation. The Cl- anion also has a valence of 1, it receives one electron and becomes Cl-.

• Oxygen has a valence of 2, because two electrons are involved in the covalent bond formation

• Some have multiple valences such as Fe, either Fe2+ or Fe3+

Henry’s Law Describes the diffusion rate, or dissolving of a gas

molecules into liquid. It states “For a given temperature, the rate of a

gas’s diffusion into a liquid is proportional to the partial pressure of that gas and its solubility coefficient”.

Does not apply to gases that chemically react with the solvent

CaO2 Formula• Total Oxygen Content (formula to determine

tissue oxygenation) • CaO2 = (Hb x 1.34 x SaO2) + (0.003 x PaO2)

NORMAL 17-21vol%• Amount of O2 combined with Hb + Amount dissolved in Plasma• Hb = Hemoglobin

– Normal males: 13.5 to 17.5 grams per deciliter– Normal femailes: 12.0 to 15.5 grams per deciliter

• 1.34 = number of millimeters of Oxygen that combine with each gram of hemoglobin• SaO2 = Percentage of saturated Hemoglobin with Oxygen

– Normal 92-99%• 0.003= Solubility coefficient of O2• PaO2 = Partial pressure of oxygen in the blood

– Normal value 80-100 mmHg– EX: CaO2 = (15 x 1.34 x .95) + (0.003 x 90) – 19.1 + 0.27 = 19.37 vol%

Solubility of CO2• CO2 diffuses about 22 times faster than O2 into the blood• Based on:

– Plasma being the solvent– Normal body temperature– 760 mmHg atmospheric blood pressure– The solubility coefficient for CO2 at 37C and 760 torr is 0.510 (A lot

higher than O2)– 0.510 ml CO2/ml plasma/760 torr– Reduced to – 0.510 ml CO2/ml plasma = 0.00067 ml CO2/ml plasma/torr PCo2– --------------------------------- 760 torrFurther broken down to: 0.067 vol%

PAO2 formula• Called the Alveolar air equation• PAO2 = FIO2 (PB- PH2O) – PaCO2 /RQ• PAO2 = Alveolar air equation

– Normal 100 mmHg• FIO2 = Fractional inspired Oxygen

– Room air = 21%, with supplemental Oxygen can increase to 100%• PB = Barometric pressure

– At sea level = 760 mmHg• PH2O = Water vapor pressure

– At normal BTPS = 47 mmHg• PaCO2= Partial pressure of Co2 in the blood

– Normally 35-45 mmHg, varies with ventilation status• RQ= Respiratory quotient

– Default number 0.8, this represents cellular uptake and elimination of O2 and CO2

PAO2 formula

• Inputting normal values:• PAO2= .21(760 mmHg-47mmHg)- 40 / 0.8

0.21 (713) – 50149.73 – 50 = 99.73 (rounded to 100)

This varies with changes in all the variables in the formula. Under normal lung conditions, a PAO2 of 100 results in a PaO2 of 80-100 mmHg

Definition of Pressure

• Defined as force (F) acting perpendicularly to a surface area (A)

• P = F/A• In the atmosphere the gas we breathe

(Nitrogen, Oxygen, Co2 and trace gases) are in constant motion, creating kinetic energy and FORCE applied against the surface of the earth. This is the atmospheric pressure

Atmospheric pressure

• Atmospheric pressure is usually measured by the height of a liquid in a closed, evacuated tube as shown on pages 178-179 in the text book.

• You have already learned the normal values at sea level for one atmosphere in several different pressure scales.

• At altitudes above sea level the atmospheric pressure is lower because there is less air pushing down on the surface.

• At sea level, 1 ATM = 760 torr, In Denver, 1 mile above sea level, 1 ATM = 680 tor.

Atmospheric pressure units

• At sea level:– 760 mmHg– 760 torr– 1034 cmH2O– 33 ft H2O– 14.7 PSI– 29.9 inHg– 101.33 kPa

– *in respiratory we will use mmhg/torr

As elevation goes up

Barometric pressure

goes down.

This is an inverse relationship.

• Fluids (air and water) flow from areas of high pressure to areas of low pressure.

• Change in pressure across a horizontal distance is a pressure gradient.

• Greater the difference in pressure and the shorter the distance between them, the steeper the pressure gradient and the high the velocity of flow

• In the lung, flow travels to the alveoli based on the diameter of the airway and also the pressure gradient. We will learn about this in another lecture

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speed, velocity, and flow.

• Speed is a measurement of an object’s movement in units of distance or length /time, (ie cm/sec, miles per hour).

• Velocity is the speed of an object with its direction at a given instant, (ie 50 miles/hour South).

• Fluid flow is a special kind of velocity expressed in units of volume/time, ie ml/sec, l/min. Remember that a fluid is a substance capable of flowing ---a gas or liquid.

Kinetic Theory of Matter

• The Kinetic Theory of Matter is the theory that all molecules are in constant motion resulting in kinetic energy. This theory applies to all three states of matter -- solids, liquids and gases.

Solids – have a high degree of internal order; their atoms have a strong mutual attractive force

Liquids – atoms exhibit less degree of mutual attraction compared with solids, they take the shape of their container, are difficult to compress, exhibit the phenomenon of flow

Gases – weak molecular attractive forces; gas molecules exhibit rapid, random motion with frequent collisions, gases are easily compressible, expand to fill their container, exhibit the phenomenon of flow

States of Matter

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Change of State (cont.)Heat transfer

◦ Conduction – transfers heat in solids

◦ Convection – transfers heat in liquids and gases

(Example: heating homes or infant incubators)

◦ Radiation – occurs without direct contact between two substances - example: microwave oven

◦ Evaporation/Condensation: requires heat energy to occur

◦ Sublimation - change from a solid to a gas without an intermediate change to a liquid - example dry ice turning into CO2 http://www.youtube.com/watch?v=lxPDAh4je54

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Change of State (cont.)Pascal’s Principle. Liquid pressure depends only on the height and weight density of the liquid and not the shape of the vessel or total volume of a liquid.

Pascal's law• Pascal's law states that pressure exerted anywhere in a confined

incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure ratio (initial difference) remains the same.

• Pascal’s Law states that when you apply pressure to confined fluids (contained in a flexible yet leak-proof enclosure so that it can’t flow out), the fluids will then transmit that same pressure in all directions within the container, at the same rate.

The simplest instance of this is stepping on a balloon; the balloon bulges out on all sides under the foot and not just on one side. This is precisely what Pascal’s Law is all about – the air which is the fluid in this case, was confined by the balloon, and you applied pressure with your foot causing it to get displaced uniformly.

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Change of State (cont.) Cohesion and adhesion

◦ The attractive force between like molecules is cohesion.

◦ The attractive force between unlike molecules is adhesion.

The shape of the meniscus depends on the relative strengths of adhesion and cohesion.

H20: Adhesion > Cohesion Mercury: Cohesion > Adhesion

H20 Mercury

Cohesion and Adhesion

• Cohesion: Water is attracted to waterAdhesion: Water is attracted to other substances

• Adhesion and cohesion are water properties that affect every water molecule on earth and also the interaction of water molecules with molecules of other substances. Essentially, cohesion and adhesion are the "stickiness" that water molecules have for each other and for other substances.

• The water drop is composed of water molecules that like to stick together, an example of the property of cohesion. The water drop is stuck to the end of the pine needles, which is an example of the property of adhesion. Notice I also threw in the all-important property of gravity, which is causing the water drops to roll along the pine needle, attempting to fall downwards. It is lucky for the drops that adhesion is holding them, at least for now, to the pine needle.

• http://www.youtube.com/watch?v=VHnFMPxteGo

Humidity and Aerosol

• Vapor pressure – Pressure water as a vapor or gas exerts and is part of the total atmospheric pressure. Water vapor pressure in the lungs exert 47 mmHg

• Absolute Humidity – the actual amount (in mg./l) of water vapor in the atmosphere

• Relative Humidity – the percent of water vapor in the air as compared to the amount necessary to cause saturation at the same temperature.

• % Body Humidity – the relative humidity at 37 degrees Celsius• Humidity Deficit – the amount of water vapor needed to

achieve full saturation at body temperature (44 mg/l - A.H)

Vapor pressure

Vaporization: the change of matter from a liquid to a gaseous form

Water vapor pressure – the direct measure of the kinetic activity of water vapor molecules

Reducing the pressure above a liquid lowers its boiling point. Ex. water boiling in mountains

• That is, since water vapor partial pressure must be 47 mmHg in a saturated gas mixture at 37°C, the total pressure remaining for the inspired gases is only 760-47 or 713 mmHg. The composition of this remaining gas is 21% O2 and 79% N2, giving the partial pressures indicated above which is then substrated by the partial pressure of PaCO2 (PACO2, is a product of the amount of CO2 diffused into the lung)

• PAO2 = FIO2 (Pb-PH2O) – (PaCO2/0.8)

Water Vapor Pressure

Humidity and Aerosol

• Solutions Used• Sterile water used in humidifiers and continuous

nebulizers (Hypotonic)• (Normal) Isotonic saline (.9% Na) with (Aerosol /

Medicine) Treatments• Hypertonic saline (10%) (for sputum induction)

Formulas Used When Calculating Humidity

• %RH=(absolute humidity/saturated capacity) x 100• %BH = (absolute humidity/43.8mg/L) x 100

Importance of HumidityIf the upper airway were bypassed or dry

gases were inhaled, a series of adverse reactions could occur, including:

– Slowing of mucus movement – Inflammatory changes and possible

necrosis of pulmonary epithelium – Retention of thick secretions and

encrustation – Bacterial infiltration of mucosa

(bronchitis) – Atelectasis – Pneumonia– Impairment of ciliary activity

Sign/Symptoms of Inadequate Airway Humidification

• Atelectasis• Dry, nonproductive cough• Increased airway resistance• Increased in incidence of

infection• Increased work of

breathing• Substernal pain• Thick, dehydrated

secretions

Aerosol Therapy

• It is important to remember that an aerosol is not the same as humidity.

• Humidity is water in a gas in molecular form, while an aerosol is liquid or solid particles suspended in a gas.

• Examples of aerosol particles can be seen everywhere: as pollen, spores, dust, smoke, smog, fog, mists, and viruses.

Aerosol Therapy• Aerosol therapy is designed

to increase the water content delivered while delivering drugs to the pulmonary tree

• Deposition location is of vital concern

• Some factors that affect aerosol deposition are aerosol particle size and particle number.

Particle Size

The particle size of an aerosol depends on the device used to generate it and the substance being aerosolized.

Particles of this nature, between 0.005 and 50 microns, are considered an aerosol.

The smaller the particle, the greater the chance it will be deposited in the tracheobronchial tree.

Particles between 2 and 5 microns are optimal in size for depositing in the bronchi, trachea and pharynx.

Deposition

• The aerosol particles are retained in the mucosa of the respiratory tract. They get stuck!

• The site of deposition depends on size, shape, motion and physical characteristics of the AIRWAYS

Mechanism resulting in Deposition: Inertial Impaction

• Moving particles collide with airway surface. – Large particles (>5micros), upper and large

airways• Physics: the larger the particle, the more

likely it will remain moving in a straight line even when the direction of flow changes.

• Physics: greater velocity and turbulence results in greater tendency for deposition

Mechanism resulting in Deposition: Sedimentation

• Particles settle out of aerosol suspension due to gravity.

• The bigger it is the faster it settles!

• Medium particles: 1-5 microns, central airways

• Directly proportional to time.• The longer you hold your

breath the greater the sedimentation

Mechanism resulting in Deposition: Diffusion

• Actual diffusion particles via the alveolar-capillary membrane and to a lesser extent tissue-capillary membranes of respiratory tract

• Lower airways: 2-5 microns

• Alveoli: 1-3 microns • These values are from

your book

Deposition of Particles is also affected by:

• Particle inertia (repeated) - Affects larger particles which are less likely to follow a course or pattern of flow that is not in a straight line.

• As the tracheobronchial tree bifurcates, the course of gas flow is constantly changing, causing deposition of these large particles at the bifurcation.

Deposition of Particles is also affected by:

• Composition or nature of the aerosol particles - Some particles absorb water, become large and rain-out, while others evaporate, become smaller and are conducted further into the respiratory tree.

• Hypertonic solutions absorb water from the respiratory tract, become larger and rain-out sooner.

• Hypotonic solutions tends to lose water through evaporation and are carried deeper into the respiratory tract for deposition.

• Isotonic solutions (0.9% NaCl) will remain fairly stable in size until they are deposited.

Boyle’s Law

• This law is named for Charles Boyle, who studied the relationship between pressure, p, and volume, V, in the mid-1600s.

• Boyle determined that for the same amount of a gas at constant temperature,

p * V = constant• This defines an inverse relationship:

when one goes up, the other comes down.

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pressure

volume

Boyle’s Law

• This law is named for Charles Boyle, who studied the relationship between pressure, p, and volume, V, in the mid-1600s.

• He determined that for the same amount of a gas at constant temperature,

p * V = constant• This defines an inverse relationship:

when one goes up, the othercomes down.

NEXTPREVIOUSMAINMENU

pressure

volume

What does Boyle’s Law mean?

p * V = constantSuppose you have a cylinder with a piston in the top so you can change the volume. The cylinder has a gauge to measure pressure, is contained so the amount of gas is constant, and can be maintained at a constant temperature.

A decrease in volume will result in increased pressure.

Hard to picture? Let’s fix that!

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A factor in breathing: For inhalation to occur,

1. Diaphragm muscle flattens/moves down

2. Increases the volume of the chest cavity

3. Pressure within the chest decreases

4. Air pressure within the lung is now less than atmospheric air pressure

5. Air flows into your lungs.

Charles’ Law• This law is named for Jacques Charles, who studied

the relationship volume, V, and temperature, T, around the turn of the 19th century.

• He determined that for the same amount of a gas at constant pressure,

V / T = constant• This defines a direct relationship:

an increase in one results in an increase in the other.

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volume

temperature

What does Charles’ Law mean?

V / T = constantSuppose you have that same cylinder with a piston in the top allowing volume to change, and a heating/cooling element allowing for changing temperature. The force on the piston head is constant to maintain pressure, and the cylinder is contained so the amount of gas is constant.

An increase in temperature results in increased volume.

Hard to picture? Let’s fix it (again)!NEXTPREVIOUS

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COMBINED GAS LAW

• States: “The state of an amount of gas is

determined by its pressure, volume, and temperature”

• The absolute pressure of a gas is inversely related to the volume it occupies & directly related to its absolute temp.

P1 x V1

T1

P2 x V2

T2=

Gay-Lussac’s Law: “With volume remaining constant, pressure and temperature are directly related”

DALTON’S LAW OF PARTIAL PRESSURE

States: “The sum of the partial pressures of a gas mixture equals the total pressure of the system and that the partial pressure of any gas within a gas mixture is proportional to its % of the mixture”.

Example:

OXYGEN = 21% NITROGEN = 78%

TRACE GASES = 1%100% Atmospheric

At 100% atmospheric,these gases exert a pressureof 760mmHg at sea level