Physics chap 3 Flashcards
Physics is
The study of motion, matter, and energy interaction
Knowledge of physics helps to understand…
body mechanics physiology that is the backbone of medicine
Newton’s First Law of Motion
An object at rest or moving at constant speed in a straight line will continue in that state until a net external force acts upon it. This is the law of inertia.
Newton’s Second Law of Motion
-Force is equal to mass times acceleration
F=m x a
-If multiple forces exist, the direction and acceleration are proportional to the sum of all the forces. These are called VECTORS.
Newton’s Third Law of Motion
For every action there is equal and opposite reaction
Mass is the
total of all matter in an object: sum of ALL protons, electrons, neutrons. From a physics perspective, mass is the resistance of an object to acceleration.
- Measured in KILOGRAMS
Larger mass requires
a greater force than a smaller mass.
Weight is
total effect of gravity pulling on all these electrons, protons, and neutrons of an object.
-Measured in NEWTONS
Average velocity
displacement/time
Has a vector quanitity and has direction.
Speed is
distance/time
Scalar quantity with no particular direction
Vectors
have magnitude and direction
What determines axis deviation of the heart?
ECG uses vector analysis
Resultant vector
when two or more vectors are added
The end of the tip is called the
head
the other end of a vector is called the
tail
Acceleration
change in velocity/change in time
Force
the amount of energy required to move an object
A newton is
Force required to accelerate a 1kg weight 1 meter per second
Dyne is
100000th of a newton
small scale used for blood. Ex: SVR, PVR
Force measurement in accelerometry is used to measure
accelerometry is used to measure the degree of neuromuscular bockade
Ulnar nerve is stimulated contraction of
adductor pollicis
Explain TOF
quantification of the degree of neuromuscular blockade
Gravity
universal attraction between all objects
G earth
9.81 m/s^2=32.2 ft/s^2
How does gravity affect the blood flow in lungs?
In standing position, distribution of pulmonary blood flow is UNeven due to gravity. lowest at apex and highest at the base of lung (will get more blood and oxygen )
-Supine blood flow is nearly uniform throughout the lung
Weight equals
m X g
m=mass
g= acceleration due to gravity
SI unit of mass is
kg
1 slug= ______kg
=14.62 kg
1 lb= ____ N
4.45 N
pressure=
force/area
measured in pascal
pressure is
force per unit area
Bourdon gauges
measure pressure in gas cylinders
P total =P gauge + P atmosphere
used in anesthesia to measure pressure in gas cylinders
True zero pressure
Zero reference point may be a complete vaccum
Zero alveolar pressure means
at atmospheric pressure
Manometer is
u shaped tube filled with fluid of known density, such as mercury. Remember what mercury density was? :)
Calculate the pressure difference between the system and the atmosphere by measuring
height distance of the fluid in the U-shaped tube and substituting for the equation:
change in P=pg times change in h
Aneroid bellows gauge
-does not require presence of a liquid to operate
-relies on the expansion or contraction of bellows as the pressure changes
-gauges sealed with respect to the atmosphere are used to measure changes in the absolute pressure
-gauges open to the atmosphere and sample are used to measure gauge pressure
Bourdon Gauge
- Used on gas cylinders and are considered a type of aneroid gauge.
- Has a coiled tube and is used to measure the pressure difference between the pressure exerted by the gas in a cylinder and the atmospheric pressure.
- As gas at a pressure above atmospheric pressure enters the coiled tube, the tube slightly uncoils,
PSI=
pounds per square inch
Atmospheric pressure is
pressure that is “zero” referenced against a perfect vacuum, so it equals the gauge pressure plus the atmospheric pressure
Gauge pressure
pressure that is “zero” referenced against ambient air pressure
-equal to absolute pressure minus atmospheric pressure
Gauge pressure and total pressure
- vital that you specify what type of pressure is being utilized and how that pressure was determined
- Total pressure (absolute pressure) includes the atmospheric pressure plus the gauge pressure: P total(absolute) = P gauge + P atmosphere
Oscillometry
method that relies on the measurement of blood pressure oscillations
transducer
device that converts pressure into electrical signals suitable for the display and monitoring
value of pascal
Pa=1N/1m^2
Pa=102g/m^2
kPa=102kg/m^2
Mean QRS vector tends to point where?
Towards ventricular hypertrophy and away from MI
atmospheric pressure conversions?
1 atm=760mmHg=760torr=1 bar=100kPa=1020 cmH2O=14.7 lb/in^2
Absolute pressure
pressure that is zero referened against a perfect vacuum so it equals the gauge pressure plus the atmospheric pressure
Barometer
measures the actual pressure or aboslute pressure
what measures gauge pressure?
Manomoeters and bourdon gauges
Does electromagnetic radiation have mass?
No.
What is normal SVR
900-1200 dyne sec/cm5
What is normal PVR
100-200 dyne sec/cm5
Pa= ____N/1m2
1N/1m2
Pa= _____ g/m2
102 g/m2
Pa= ____kg/m2
102g/kg2
1N= ____grams
102 grams
___ kPa= ____ cmH20= ___ mmHg
- 1
- 10.2
- 7.5
___ torr= ____ mmHg
- 1 torr
- 1 mmHg
____mmHg= ____ cmH20
- 1 mmHg
- 1.34 cmH2O
____ atm= ____ mmHg= ___ torr= ___bar= ____kPa= ____ cmH2O= ____ lb/inch2
- 1 atm
- 760 mmHg
- 760 torr
- 1 bar
- 100kPa
- 1020 cmH2O
- 14.7 lb/inch2
