CVT 100 #5 PHYSICS WEEK 6 EXAM REVIEW Flashcards
What is the definition of Force
mass x acceleration
What is the definition of mass
a quantity of stuff
can be defined by how much force it takes to change its state…
What is the definition of Pressure
force per unit area
Define Resistance
opposition to movement
Definition of Flow
volume per unit time
Velocity
distance per unit time
Units for force & pressure
SYSTEM: SI
Force:
Pressure:
Force : Newton (kg*m/sec^2)
Pressure: Newtons/m^2
Poiseuille’s Law:
• Resistance equation Flow equation •
Expressions of ∆P
P1 - P2 or P1 - P2
———- ———-
Time Length
Units for force & pressure
SYSTEM: CGS
Force:
Pressure:
Units for force & pressure
SYSTEM: CGS
Force: dyne (g*cm/sec^2)
Pressure: dynes/cm^2
Units for force & pressure
SYSTEM: British
Force:
Pressure:
Units for force & pressure
SYSTEM: British
Force: Slug (slug*ft./sec^2)
Pressure: lb./inch^2
Two ways to increase blood flow from heart during exercise:
- Increase heart rate
2. Increase force of myocardial contraction
Frank-Starling Law:
More filling,
more stretch —> more forcible contraction (more contractile force)
Balloon analogy: blow up a little, little force; blow up a lot, more force on release.
Or rubber band analogy: pull a little bit, little force; pull a lot, more force.
Function in Systole
Open Valves
Closed Valves
Systole Contraction, ejection
Approximately 1/3 of the cardiac cycle
Open valves: Aortic and pulmonic
Closed valves: Mitral and tricuspid
Function during Diastole
Open Valves
Closed Valves
Diastole Relaxation
Approximately 2/3 of the cardiac cycle
Open valves: MV and TV
Closed valves: AoV and PV
Distribution of blood volume:
About 1/3 in the arterial side,
and about 2/3 in the venous side.
Right heart provides energy for the
pulmonary circulation.
Left heart provides energy for the
systemic circulation.
The net effect of exercise is usually an increase of
systemic blood pressure.
What is acceleration?
Change of speed and/or direction.
Strictly speaking, velocity implies both speed and direction.
Converting mmHg to dynes/cm2
1 mmHg = 1333 dynes/cm2
( it’s okay for our purposes to use 1.3 x 103)
So, 120 mmHg = ________ dynes/cm2
To change dynes/cm2 to mmHg
DIVIDE by (1.3 x 10^3)
Starling’s Law
Increased LV filling,
increased myocardial stretch,
increased force of contraction
Exercise physiology:
•Muscle contraction —>
collapse veins More blood goes to heart and arterial side
•More force of contraction (Starling) —> higher BP
More blood from heart due to:
a) stronger contractions, and
b) increased heart rate
Arterioles dilate in response to
local chemistry (metabolites) —> decreased resistance in muscles —> more flow to muscles
Viscosity
"is the measure of a fluids resistance to flow and deformation due to stress Common symbol(s): η, μ
SI unit: Pa·s = kg/(s·m)
Pressure drops across segments of circulation.
- 1st Arteries
- Aorta
- Large arteries
- Branch arteries
- 2nd Arterioles
- 3rd Capillaries
- 4th Venules and veins
2/3 to 3/4 of the blood is in our …
venous cycle because it needs to go back to the heart for SaO2.
arterioles control the flow of the system because they control …
the diameter by adjusting the resistance. When the arterioles are contracted they are constricting the flow and when they are relaxed they dilate the vessels.
The largest drop is in the____________because…
The largest drop is in the ARTERIOLES
BECAUSE: they control the flow by constricting and dilating the vessels.
Force/pressure/area
Flow/∆P/resistance
mmHg to/from dynes/cm2
and
L/min to/from cm3/sec
Force/pressure/area
Flow/∆P/resistance
mmHg to/from dynes/cm2
and
L/min to/from cm3/sec
Expressions of ∆P •
P1 - P2 or P1 - P2
———- ———-
Time Length
WHAT HEART VALVES ARE OPEN DURING SYSTOLE?
AO AND PV
AORTIC VALVE AND PULMONARY VALVE
WHICH VALVES ARE OPEN DURING DIASTOLE?
MV AND TV
Mitral valve and Tricuspid Valve
CHARACTERISTICS OF VESSELS: ARTERIES: Velocity Pressure Resistance Volume
ARTERIES HAVE: HIGHEST VELOCITY HIGHEST PRESSURE LOW TO MODERATE RESISTANCE ~12% VOLUME
CHARACTERISTICS OF VESSELS: ARTERIOLES: Velocity Pressure Resistance Volume
ARTERIOLES HAVE: LOWER VELOCITY LOWER PRESSURE HIGHEST RESISTANCE ~2% VOLUME
CHARACTERISTICS OF VESSELS: CAPILLARIES: Velocity Pressure Resistance Volume
CAPILLARIES HAVE: LOWEST VELOCITY LOWER PRESSURE LOW TO MODERATE RESISTANCE ~5% VOLUME
CHARACTERISTICS OF VESSELS: VEINS: Velocity Pressure Resistance Volume
VEINS HAVE: VELOCITY UP AGAIN LOWEST PRESSURE LOWEST RESISTANCE ~2/3 VOLUME
When would you measure AORTIC STENOSIS?
Where would you measure?
MEASURE VELOCITY AT SYSTOLE
MEASURE PRESSURE IN THE LV AND AO INCREASED PRESSURE IN THE LV
When would you measure MV STENOSIS?
Where would you measure?
MEASURE VELOCITY AT DIASTOLE
MEASURE PRESSURE IN THE LA AND LV INCREASED PRESSURE IN THE LA
Sx of LE arterial obstructive disease Claudication:
pain with exercise, relieved by rest
Usually calf, possibly progressing to thigh, hip, buttock
WHENEVER YOU HAVE A NARROWING/STENOSIS, YOU HAVE A LOSS OF ENERGY WHERE?
DISTAL TO THAT STENOSIS.
WHEN WOULD YOU ASSESS FOR AN AORTIC STENOSIS?
DURING SYSTOLE
WHERE WOULD I FIND THE HIGHER PRESSURE?
IN THE LV
WHEN WOULD YOU ASSES FOR MITRAL VALVE STENOSIS?
DURING DIASTOLE
WHERE WOULD YOU FIND THE HIGHER PRESSURE?
IN THE LA
WHAT DOES A SIGNIFICANT GRADIENT BETWEEN THE CUFFS SUGGEST?
THAT THERE IS SOME STENOSIS BETWEEN THE CUFFS.
