Exam II Flashcards
What is Solubility?
The maximum amount of one substance (solute) that is able to dissolve into another (solvent).
Factors of Solubility
Intermolecular interactions
Temperature
Pressure
How do intermolecular interactions affect solubility?
“Like-dissolves-like”
Polarity/ionization
Similar electron configuration = higher solubility
How does temperature affect solid/liquid solubility?
Elevated temp = increased solubility
How does pressure affect solubility?
Higher pressure increases solubility (Henry’s Law - gases)
Endothermic Reactions
Reaction that requires/uses energy.
Exothermic Reactions
Reactions that release energy.
Increased temperature reduces solubility.
Effect of Temperature on Gas
Inverse relationship - as temperature increases, solubility decreases.
Henry’s Law
p = kc
The solubility of gas is directly proportional to pressure.
Diffusion
The net movement of one type of molecule through space as a result of random motion intended to minimize concentration gradient.
Ex. Food coloring in water.
Osmosis
The movement of water across a semipermeable membrane to equilibrate a concentration gradient.
Graham’s Law
r = 1/,^mw (square root)
The rate of effusion of a gas is INVERSELY proportional to the square root of its molecular weight.
Small = Faster diffusion
Fick’s Law
Diffusion of gas is DIRECTLY proportional to:
-Partial pressure gradient
-Membrane solubility
-Membrane area
INVERSELY proportional to:
-Membrane thickness
-Molecular weight
Fick’s Law Application to Anesthesia
Passive Oxygenation - ENT cases
Diffusion Hypoxia
Concentration Effect
Second Gas Effect
What is diffusion hypoxia?
Nitrous is very soluble
tissues become saturated, diffuse into alveoli quickly once turned off, creating hypoxic mixture in the lungs <21%
What is concentration effect?
Increasing the fraction of inspired concentration (FI) of an inhalation anesthetic will more rapidly increase the fraction of alveolar concentration (FA) of the agent– think about Henry’s law
What is the second gas effect?
As nitrous is diffused into the blood from the alveoli at a faster rate than the volatile anesthetic, it leaves a void of volume in the alveoli. It creates pressure gradient, allowing more volatile anesthetic to enter the alveoli at a faster rate.
Tonicity
The capacity of a solution to modify the volume of a cell by altering its water content.
Hypotonic
Na concentration <130 mEq/L
Cytolysis = Cells in hypotonic fluid absorb too much water and burst.
Isotonic
Na concentration between 130-155 mEq/L
Hypertonic
Na concentration >155 mEq/L
Plasmolysis = Cells in hypertonic solution lose water and shrink.
What is an acid?
A substance that can donate a proton (H+) or accept an electron pair in a chemical reaction.
What is a base?
A substance that can accept a proton (H+) or donate an electron pair in a chemical reaction.
What is pH?
Measure of acidity or alkalinity of a solution, qualifies, the concentration of H+ ions in a solution.
pH range = 0-14
What is an acid-base reaction?
Occurs when an acid and a base react to form water (H2O) and salt (an ionic compound).
Acid + Base = Water + Salt
What is a buffer and an ex. of one?
Help regulate and stabilize pH
CO2 + Water <–> carbonic acid <–> HCO3 + H+
What is pKa?
A specific value associated with a weak acid or weak base.
It represents the pH at which half of the molecules of that substance are ionized (dissociated) and half are in their non-ionized (undissociated) forms.
CONSTANT.
pH Equation
pH = pKa + log[A-]/[HA]
or
pH = -log[H+]
What is a non-ionized molecule?
Molecule that has not gained or lost an extra hydrogen ion.
Carries a negative charge.
Lipophilic = cross membranes easily.
EFFECTIVE.
What is an ionized molecule?
Molecule that has gained an extra hydrogen ion.
Carries a positive charge.
Hydrophilic = does not cross membranes easily.
INEFFECTIVE
What is “like-dissolves-like”?
Non-polar solutes dissolve in non-polar solvents.
Ionic/polar solutes dissolve in polar solvents.
Partial Pressure
Proportion pressure of a single type of molecule in a gas.
If the proportion of a gas goes up, the partial pressure goes up.
The likelihood of a solute entering a solvent at a given temperature.
Molality
Moles solute / kg solvent
Vapor Pressure Lowering
Solutes block the ability of the solvent to spontaneously enter the air, leading to decreased vapor pressure.
More solutes = lower vapor pressure.
Boiling Point Elevation
Presence of solute molecules interferes with the solvents ability to escape the liquid.
More solutes = elevated boiling point.
Freezing Point Depression
Presence of solute molecules interferes with the solvents ability to form a latus.
More solutes = depressed freezing point.
Ex. Salt added to ice on roads.
What is concentration?
Measure of how much solute is present per volume of solvent.
Bronsted-Lowry Acid
Proton donor
Bronsted-Lowry Base
Proton acceptor
Lewis Acid
Electron pair acceptor (electrohpile)
Lewis Base
Electron pair donor (nucleophile)
[HA]
Acid
[A-]
Conjugate base
The Buffer System
CO2 + H2O <–> Carbonic Acid <–> HCO3 + H+
What does a buffer consist of?
A weak acid and its conjugate base.
Henderson-Hasselbalch Equation
pH = pKa + log[A-]/[HA]
[A-] = [HA]
pH = pKa
[A-] > [HA]
pH > pKa
[A-] < [HA]
pH < pKa
Oncotic Pressure
Pressure exerted by large molecules, such as proteins, albumin, and poly-carbs that cannot pass through the semi-permeable membrane.
Creates an osmotic pressure.
Example of Oncotic Pressure
Arterial capillaries have a hydrostatic pressure (filtration pressure) that exceeds the oncotic pressure (absorption pressure) and flow is created out of the capillaries.
Venous capillaries’s oncotic pressure exceeds the hydrostatic pressure and therefore flow is generated back into the capillary system.
Viscosity
The ability of a liquid to resist flow.
SI unit for viscosity = Pa s (pascal seconds)
Factors that Determine Viscosity
Strength of intermolecular forces.
Size/shape of the molecule.
Temperature.
Two types of intermolecular forces?
Cohesive
Adhesive
Cohesive Forces
Intermolecular forces between the molecules of a liquid.
The attraction that molecules exhibit between one another that cause cohesion.
Adhesive Forces
Interactions between the liquid and a solid surface.
Why do water molecules form spheres?
To maximize hydrogen bonding by decrease surface area.
Molecules on the edge only half the effect of hydrogen bonding.
Concave meniscus is an example of what force?
Adhesive > Cohesive
Convex meniscus is an example of what force?
Cohesive > Adhesive
Surface Tension
Energy require to increase the surface area of a liquid.
Dependent on strength of the cohesive force in liquid.
Equation of Continuity
Flow rate = area x velocity
The FLOW RATE depends on the cross-sectional AREA of the pipe and the VELOCITY of the fluid.
Velocity is INVERSELY proportional to area.
Bernoulli’s Principle
The higher the fluid’s velocity is through a pipe, the lower the pressure on the pipe’s walls, and vice versa.
Constant = P + (1/2p x v^2) + (p x g x y)
Venturi Effect
A constricted pipe leads to a faster velocity and a lower pressure.
Ex. Venturi Mask
Laminar Flow
Smooth even flow. Minimal mixing of layers. No random velocity changes. Fluid flows steadily in one direction.
Ex. Blood flow
Turbulent Flow
Velocity is fluctuating. Contains swirls and eddies.
Ex. Smoke from a chimney.
Layers of Turbulent Flow
Laminar sublayer
Buffer layer
Turbulent boundary
Reynold Number Equation
Re = puL / u (mu)
p = fluid density
u = velocity
L = Length
u (mu) = dynamic viscosity
puL
Inertial forces = force which cause fluid to move.
u (mu)
Viscous forces = frictional forces due to fluid viscosity
If inertial forces dominiate?
Turbulent flow
If viscous forces dominate?
Laminar flow
Re Predictions
<2000 = laminar
2000-4000 = transitional
>4000 = turbulent
What would the heart have to work harder if blood flow was turbulent?
The pressure drop is greater in turbulent flow.
As the blood gets further from the heart, the pressure drops.
What is hydrostatics?
Characteristics of fluids at REST and the pressure in a fluid or exerted by a fluid on an immersed body.
What is hydrodynamics?
MOTION of fluids and forces acting on solid bodies immersed in fluids and in motion relative to them
What law calculate laminar flow rate?
Poiseuille’s Law
Poiseuille’s Law
Flow rate = (pie)(r4) x (P1-P2) / 8nL
Conditions for Poiseuille’s Law
Fluids must have laminar flow.
Incompressible fluid.
Poiseuille’s Law - Increased Radius
Increased flow rate
Poiseuille’s Law - Increase Viscosity
Decreased flow rate
Poiseuille’s Law - Increased Length
Decreased flow rate
Poiseuille’s Law - Increased Pressure
Increased flow rate
Ex. of Poiseuille’s Law
Blood vessels with atherosclerosis = decreased radius = decreased flow rate = increase pressure from heart
Law of Laplace r/t CV
Wall Stress = Pressure x Radius / Wall Thickness
Wall Stress is DIRECTLY proportional to…
Pressure and Radius
Wall Stress is INVERSELY proportional to…
Wall Thickness
The heart wall will thicken in attempted to decrease wall stress due to chronic hypertension.
Surface Tension
Measure of the contractive tendency that allows liquids to resist deformation by an external force.
Law of Laplace
P = 2T / r
P = Pressure
T = Tension
r = Radius
(LOL) Pressure is DIRECTLY proportional to…
Tension
(LOL) Pressure is INVERSELY proportional to…
Radius
Surfactant
Prevents atelectasis
A compound that reduces surface tension when added to a liquid.
Pulmonary Surfactant
Complex lipoprotein formed by type II pneumocytes lining the alveoli.
Ex. DPPC
Effects of Surfactant on Surface Tension
Roughly proportional to surface area.
Most pronounced when alveoli are smaller.
Effects of Surfactant
Reduction in atelectasis
More even distribution of ventilation amongst the alveoli.
Improved lung compliance.
Longitudinal Waves
Particles vibrate parallel to the direction in which the wave of energy is traveling.
Ex. Sound
Transverse Waves
Particles vibrate at 90 degrees and move horizontally.
Ex. Ocean waves.
Wave Properties
Frequency
Period
Wavelength
Amplitude
Frequency
The number of complete waves passing a fixed point in a given amount of time.
Usually over 1 second.
SI Measurement = Hertz (Hz)
Period
The time for one complete cycle.
Measured in seconds.
Periodic = happens repeatedly
Wavelength
Distance between the point on one wave to the same point on the next wave.
Measured in meters (lambda).
Amplitude
Distance from the maximum disturbance to the undisturbed position (flat).
Ex. Waves at sea. Height of wave = amplitude.
What is rarefraction?
Area in longitudinal wave where the particle are far apart.
What is compression?
Area in longitudinal waves where the particles are close together.
Doppler Effect
As a source approaches an observer (or vice versa) the wavelength decreases, and therefore the frequency increases.
Inverse Square Law
Change in intensity due to change in distance.
Decreased distance = increased intensity (or vice versa).
Ex. Xray or flashlight.
