Chemistry and physics 2 Flashcards
Boyle’s law is at a
constant temperature, the volume and pressure of a gas are inversely proportional
as the volume decreases, the pressure increases
Applications of Boyle’s law include
diaphragm contraction increases tidal volume
pneumatic bellows used for positive-pressure ventilation
squeezing a bag valve mask
using the bourdon pressure gauge to calculate how much O2 is left in a cylinder
Charles’ law states that
at constant pressure, the temperature and volume of a gas are directly proportional
heated gas tends to expand
Application of Charles’ law includes
LMA cuff ruptures when placed in an autoclave
Gay-Lussac’s law states that
at a constant volume, the temperature and pressure of a gas are directly proportional
-heated gas tends to increase the pressure in a containe
Application of Gay-Lussac’s law is
oxygen tank explodes in a hot environment
The ideal gas law
unifies all three gas laws into a single equation
What is the ideal gas law?
PV=nRT
P= pressure
V= volume
n= number of moles
r= constant 0.0821
t= temperature
Boyle’s law equation is
P1V1=P2V2
Charles’ law equation is
V1/T1=V2/T2
Gay-Lussac’s Law is
P1/T1=P2/T2
What is meant by “Paid TV can be great”
It is the mnemonic used to remind which variables remain constant in each gas law:
P= pressure, T= Temperature, V= volume, C= Charles, B=Boyles, G= Gay-Lussac
During laminar flow, quadrupling the radius will cause flow to increase by a factor of:
256
__________- states that the current passing through a conductor is directly proportional to the voltage and inversely proportional to the resistance
Ohm’s law
Ohm’s law can be adapted to understand ______________ where flow is ________________ to the pressure gradient and ___________ to the resistance
fluid flow; directly proportionate; inversely proportional
Poiseuille’s law is a modification of Ohm’s law that incorporates
vessel diameter, viscosity, and tube length
Poiseuille’s law is also known as the
Hagen-Poiseuille equation
Altering the __________- has the greatest impact on flow
radius
Doubling the radius, increases flow by a factor of
16
Applications of Poiseuille’s law include
selecting a large-bore IV (instead of a small one) increases flow
polycythemia reduces microvascular flow
carotid stenosis reduces flow through the carotid artery
Flow is defined as the
movement of electricity, fluid, or air per unit time
Ohm’s law can be adapted into a flow equation:
Flow= pressure gradient/resistance
Poiseuille’s Law equation is
Q= (pie x R^4 x delta P) / 8 n x L
Q= blood flow
r= radius
delta P= arteriovenous pressure gradient (Pa-Pv)
n= viscosity
l= length of the tube
__________ is the result of friction from intermolecular forces as fluid passes through a tube
Viscosity
A fluid’s viscosity is _______________ to its temperature
inversely proportionate
decreased temperature increases viscosity and resistance
When administering PRBCs, we can deliver packed RBCs faster if we:
increase the radius with a large-bore IV
increase the pressure gradient with a pressure bag or increase the height of the IV pole
decrease the viscosity by diluting the blood with 0.9% NaCl or running it through a fluid warmer
decrease the length by not using longer tubing than you really need
Reynold’s umber is the LOWEST in the:
a. glottis
b. medium-sized bronchi
c. carina
d. terminal bronchioles
d. terminal bronchioles
What are the three types of flow?
laminar
turbulent
transitional
Reynolds’ number allows us to
predict the type of flow that will occur in a given situation
Laminar flow is defined as
Re <2000
All the molecules in laminar flow travel in
a parallel pattern
An example of laminar flow is
airflow in the terminal bronchioles
blood flow in the systemic circulation
Turbulent flow is defined as
Re>4,000
All the molecules in turbulent flow travel in a
chaotic pattern
Examples of turbulent flow include
airflow through medium-sized bronchi
Transitional flow is defined as
Re= 2,000-4,000
Transitional displays a
turbulent pattern in the center of the tube and a laminar pattern near the walls of the tube
Reynolds’ number equation is
(density x diameter x velocity)/ viscosity
Laminar flow is dependent on
gas viscosity
Turbulent flow is dependent on
gas density
With laminar flow, due to cohesive forces, the molecules in the center of the tube travel at
the fastest rate while the molecules near the walls of the tube travel at the slowest rate
Turbulent flow tends to be produced by a /an:
orifice (change to a narrow diameter)
high gas flow
acute angle in the tube (>25 degrees)
branching in the tube
The patient with status asthmaticus suffers from an increased airway resistance and this increases flow turbulence and the work of breathing, ________________ decreases Reynold’s number and can improve airflow when airway resistance is high
oxygen/helium mixture (Heliox)
Helium does NOT improve flow if it’s
already laminar
What law describes laminar flow? Why?
Poiseuille’s law
laminar flow is dependent on gas viscosity
What law describes turbulent flow? Why?
Graham’s law. turbulent flow is dependent on gas density
Which physical principle applies to the operation of a jet ventilator? (select 2)
a. critical pressure
b. venturi effect
c. Bernoulli principle
d. Coanda effect
b. venturi effect
c. Bernoulli principle
