Cardiovascular Biophysics (Exam IV) Flashcards
Why is the CV system necessary for hormone transport?
- Hormone transport through diffusion is too slow & too far a distance.
What examples were given for important nutrients/things moved to tissue via the CV system?
- O₂
- Ions
- Glucose
- Cholesterol
- Fatty Acids
What examples were given for important waste products removed from the tissue via the CV system?
- H⁺
- Nitrogenous waste (urea, etc.)
- Lactate (lactic acid)
The CV system also helps regulate _______ _________.
Body Temperature
What is a normal CO for A&P class?
5Lpm
What is the prototypical patient used for A&P class?
30yo M weight 70kg.
___% of blood is found in pulmonary circulation. How many liters would this be for a prototypical patient?
- 9%
- 0.45L
How much blood is found in pulmonary capillaries at any given time?
How much of total pulmonary blood volume can be shunted if needed?
- 70cc’s
- 1/2 of pulmonary blood volume.
___% of blood is found circulating through the cardiac chambers. How many liters would this be for a prototypical patient?
- 7%
- 0.35L (include atrial appendages)
___% of blood is found in large artery circulation.
How about arteriolar & capillary circulation?
Knowing these how much of total blood volume is in arterial circulation?
- 13%
- 7%
- 20% or ~ 1L
What percentage/Liters of blood is in systemic circulation? (i.e. not in lungs or heart)
- 84% ~ 4.2L
___% of blood is in veins, venules, & venous sinuses.
Where, specifically, is most of the blood?
- 64%
- Large veins (i.e. brachiocephalic, femoral, etc.)
What is the largest reservoir of blood in the human body?
Venous system.
What has a lower resistance:
- Blood vessels in series?
- Blood vessels in parallel?
- Parallel blood vessels of lower resistance (Ω). 1/R
What component of the circulatory system essentially controls blood pressure via SVR?
Arterioles
What two factors control arteriolar tone?
- Metabolic demands (open or closed arteriolar paths)
- Nervous system via NE.
What component of CV system has the largest cross sectional area (cm²) ?
What component has the lowest?
- Capillaries (~ 2500 cm²)
- Aorta (~2.5 cm²)
How long is blood actually in capillaries as it moves through the CV system?
Where is the exception to this?
- 1-2seconds
- blood moves through pulmonary capillaries faster due to only gas exchange occurring.
What is the cross-sectional area of all arterioles?
40 cm²
What is the cross-sectional area of the Vena Cavae?
How does their blood velocity compare to that of the aorta?
- 8cm²
- Lower than aorta due to increased cross sectional area.
What is the formula for MAP?
MAP = DBP + ⅓(SBP - DBP)
What is the perfect MAP for A&P lecture?
93.3 mmHg
What is the perfect MPAP (mean pulmonary arterial pressure) for A&P class?
16 mmHg
What would the lowest pressure in the LV be?
2mmHg during diastole
How would the pressure in large arteries compare to the LV & the aorta?
Why is this?
- Large arteries (femoral, brachiocephalic, etc) would have a ↑ systolic & ↓ diastolic.
- Large arteries are less compliant than the aorta.
What is the arterial capillary pressure and the venous capillary pressure?
What then would be ΔP?
- Arterial capillaries = 30mmHg
- Venous capillaries = 10mmHg
- ΔP = 20mmHg
LV pressure ________ that of the aortic pressure will open the aortic valve.
exceeding
LV pressure ____ _____ that of the aorta will close the aortic valve.
less than
Venous system pressure should be ____ mmHg.
The right atrial pressure should be ____ mmHg.
- 10mmHg.
- 0mmHg
Why is PVR (pulmonary vascular resistance) less than SVR?
- More parallel vascular pathways.
- Decreased vessel length comparatively.
What should the pressure of the RV be?
What should the pressure of the pulmonary arteries be?
What would the pressure in the pulmonary veins be?
RV = 25/0 mmHg
PAs = 25/8 mmHg
PVs = 0 mmHg
What does Reynolds number signify?
A higher number would mean what?
- The measurement of turbulent flow.
- Higher # = more turbulence
What is Reynold’s Equation?
Blood vessels can be damaged from turbulent flow. T/F?
What can get stuck in the endothelium from this?
- True
- Ca⁺⁺ & cholesterol
Thicker blood would create ______ turbulence.
less
Orderly flow along a blood vessel is known as?
Where is resistance least & greatest in this scenario?
- Laminar flow
- Ω is greatest close to vessel walls & lowest in middle of vessel lumen.
___% of blood flow from the LV goes to the brain.
14%
___% of blood flow from the LV goes to perfuse the heart.
4%
___% of blood flow from the LV goes to splachnic circulation.
27%
___% of blood flow from the LV goes to the kidneys.
Why is this?
22%, higher percentage for filtering purposes. Actually renal organ perfusion is less.
___% of blood flow from the LV goes to the skeletal muscles.
Is this variable?
- 15% for basal tone
- Variable up to 75% if necessary.
___% of blood flow from the LV goes to the skin & other tissues.
When does this change?
- 18%
- If hyperthermic this % increases to get rid of heat.
What primarily determines blood flow to organs?
Metabolic demand.
What is a normal hematocrit for A&P class?
0.4 ~ 40%
When might a lower hematocrit be useful? Why?
- Post-MI, lower hematocrit = lower η (blood viscosity) = less work.
What is Poiseuille’s equation?
- F = Flow
- ΔP = change in pressure
- r = radius of vessel
- η = blood viscosity
- l = vessel length
Conductance = ______
1 / Resistance
What is the formula for vascular resistance?
R = ΔP/F
What does PRU stand for?
How is a PRU calculated?
- Peripheral Resistance Unit
- ΔP/F → 100 - 0 / 100mL/s = 1mmHg/mL/s = 1 PRU
What is a normal wedge pressure in a healthy person?
8 mmHg.
What is a normal PVR is CGS units?
40 - 180
What is the conversion factor from PRUs to CGS units?
PRU’s · 1333 = CGUs
What is a normal SVR range in CGS units?
- 800 - 1600 dynes·sec/cm⁵
How are CGS units calculated?
SVR = ΔP/CO · 80
