Cardio I Flashcards
Formula for Cardiac Output
CO = HR x SV
True or False
Systemic blood flow = Pulmonary blood flow
True
CO at rest
5L/min
Max CO by non-athlete
20L/min
Max CO by athlete
30L/min
Pulmonic vs Systemic Circulation
Lower resistance, afterload, stroke work
But
Same preload, HR, SV, CO
Greatest blood flow per 100g of tissue
Kidneys
Example of situation where pulmonary blood flow is greater than aortic blood flow?
Left-right ventricular shunt
Control conduits of the circulation
Arterioles
Component of the circulation with the largest cross-sectional area
Capillaries
Drains proteins and fluids from the interstitium
Lymphatic vessels
Component of circulation that contains stressed volume
Arteries
Site of greatest resistance which contains adrenergic receptors
Arterioles
Capacitance vessels of the circulation
Veins
Structure of Arteries and Veins
Tunica Intima - contains endothelial cells
Tunica Media - contains smooth muscle and a1 and b2 receptors
Tunica Adventitia - made of connective tissue
Component of the circulation with slowest blood flow velocity
Capillaries
Lymph vessels in the GI tract that carries chylomicrons
Lacteals
Right Atrial Pressure is also called
Central Venous Pressure
Pressure in Right Atrium
0-4 mmHg
Lowest
Site of highest oxygenated blood
Pulmonary vein
Atrioventricular Valves
Tricuspid Valve (R)
Mitral Valve (L)
Semilunar Valves
Pulmonic Valve (R)
Aortic Valve (L)
Primer pumps of ventricles
Atrium
Atrial contraction is responsible for how many % of ventricular filling?
20%
Systolic blood pressure is highest at:
Branching points of the aorta
Ex: Renal artery
Cardiac Output Formulas:
- CO = HR x SV
- CO = BP/TPR (From Ohm’s Law - Q = P/R)
- CO = VR = VO2/AVO2 (From Fick’s Law)
Formula for Blood Flow (Ohm’s Law)
Q = P/R
Or
CO = (MAP-Right Atrial Pressure)/TPR
Formula for Blood Flow Velocity
V = Q/A
Formula for Pulmonary Vascular Resistance
PVR = (Pulmonary Artery Pressure - Left Atrial Pressure)/CO
** From Ohm’s Law: Q = P/R
Formula for Resistance to Blood Flow (Law of Poiseuille)
R = 8nl/πr4
Viscosity is determined by:
Hct = %RBC
^ Hct = Polycythemia
V Hct = Anemia
Streamline blood flow with blood velocity fastest at the center and slowest near vessel walls
Laminar Blood Flow
Irregular, disorderly blow associated with High Reynold’s number (>2000) and bruitd (audible vibrations)
Turbulent Blood Flow
Formula for Turbulence
Nr = pdv/n
P = density
d = diameter
v = velocity
n = viscosity
Partial occlusion of blood vessel leads to what kind of blood flow
Turbulent blood flow
Decreased cross-sectional area = high velocity
Formula for Capacitance/Compliance
C = V/P
V = volume
P = pressure
Normal pressure at the aorta
120/80
Normal pressure at the branching points of the aorta
Slightly higher than aorta
Normal pressure at the systemic arterioles
50 mmHg
Normal pressure at the systemic capillaries
17 mmHg
Normal pressure at the vena cava/Right Atrium
0-4 mmHg
Normal pressure at the pulmonic arteries
15-25/8-10 mmHg
Normal pulmonary capillary pressure
7 mmHg
Highest arterial blood pressure
Systolic pressure
Lowest arterial blood pressure
Diastolic pressure
Formula for Pulse Pressure or BP
- Systolic pressure - Diastolic pressure
- PP = SV/AC
SV - stroke volume
AC - arterial compliance
Most important determinant of Pulse Pressure
Stroke Volume
Formula for Mean Arterial Pressure
1/3(SBP) + 2/3(DBP)
Or
Diastole + 1/3(PP)
where
PP = SBP - DBP
How do you compute for Ejection Fraction?
EF = SV/EDV
Normal ratio of systemic to pulmonary pressure
3:1
Ratio of venous compliance to arterial compliance
20:1
How do you measure Pulmonary Capillary Wedge Pressure?
Swan-Ganz Catheter to measure Left Atrial Pressure
What increases when Central Venous Pressure increases?
ANP or Atrial Natriuretic Peptide
Causes of Increased (widened) Pulse Pressure
Note: PP = SV/AC
**Either ^ SV or decreased AC
- Well-conditioned endurance runner
- Old age
- Aortic regurgitation
- Aortic sclerosis
- Severe IDA
- Arteriosclerosis
- Hyperthyroidism
Causes of decreased (narrow) Pulse Pressure:
Note: PP = SV/AC
- Heart Failure
- Blood loss
- Aortic stenosis
- Cardiac tamponade
Vitamin Deficiency that can cause CHF or Wet Beriberi
Vitamin B1 or Thiamine Deficiency