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In healthy men the hematocrit is about :
  • 45 percent
Agents that cause pulmonary vascular constriction:
1. Isoproterenol
2. Epinephrine
3. Oxygen
4. Dopamine
  • Epinephrine
  • Dopamine
If pressure in pulm artery is 34 mmHg and pressure in left atrium 9 mmHg what is driving pressure ?
  • 25 mmHg
Graham's Law
The rate of diffusion of a gas (r) into a liquid is directly proportional to it's solubility coefficient (Cs) and inversely proportional to the square root of it's GMW.
Normal DLCO
25 mlCO/miH/mmHgCO
Normal DLO2
30 mlO2/mmHgO2/min
The tricuspid valve lies between the :
  • Right atrium and right ventricle
Compared to systemic circulation the pressure in the pulmonary circulation is about :
  • 1/10th the pressure
Which of the following cause pulmonary vasoconstriction ?
  • Hypercapnia
  • Hypoxia
  • Acidemia
  • Increased H+ concentration
All cause pulmonary vasoconsriction
Which of the following cause passive changes in pulmonary vasculaer resistance ?


  • pH changes

  • Transpulmonary pressure changes

  • PCO2 changes

  • Blood viscosity changes


  • Transpulmonary pressure changes

  • Blood viscosity changes

Normal V/Q ratio is about :
  • 0.8
In a healthy individual in the upright position the PAco2 is highest in ______ lung regions.
  • Lower
When the V/Q ratio decreases the PAO2 and PCO2 ________.
  • Decreases
When the V/Q ratio decreases the PCCO2 and PACO2 ________.
  • Increases
When alveolar ventilation is 7 L and pulmonary blood flow is 9.5 L the V/Q ratio is about _______.
  • 0.7
Respiratory Quotient (RQ) formula
RQ = VCO2
         ______
         VO2
If tissue cells consume 275ml of O2 per minute and produce 195ml of CO2 per minute what is the RQ ?
  • 0.7
Define Bronchial circulation
  • Supplies supporting tissues of the lung, connective tissue, large/small bronchi and bronchioles
  • Carries oxygenated blood to systemic tissues
Bronchial circulation route
  • Follows tracheobronchial tree to level of terminal bronchioles
  • Empties into pulmonary veins and blood is returned to left atrium rather than right
  • Makes up 1-2% of CO
Define Pulmonary circulation
  • Extends only 5cm from right ventricle before it divides
  • Thickness is only 1/3 that of aorta
  • Arteries of pulmonary circulation are thin walled with larger diameters than systemic
PVR formula
PVR= Input pressure-Output pressure
          ________________________________
                       
                           Flow
Normal PVR
20-120 dyne x sec x cm-5
Two mechanisms responsable for decreasing PVR
  • Recruitment
  • Distension
Define recruitment
  • Some capillaries are either open or closed with no blood flow.
  • As pressures rise these capillaries begin to conduct blood lowering PVR
Define distension
  • At higher pressures widening of capillaries occurs lowering PVR at higher pressures.
  • The predominant mechanism for the fall in PVR at higher pressures
Distribution of Pulmonary blood flow
  • Effect of gravity on distribution of PBF has led to concept of 4 lung zones in which different hemodynamic conditions govern blood flow
Zone 1 PA > Pa > Pv
  • Capillaries are squashed flat/no flow possible
  • Zone 1 does not exist under normal conditions
  • Pa is just sufficient to raise blood to top of lung.
Zone 2 Pa > PA > Pv
  • Blood flow determined by difference between arterial and alveolar pressures
  • Pa increases down this region while PA remains the same
  • Pressure difference is responsable for flow increase down this region.
  • The increased flow is accomadated by recruitment of capillaries.
Zone 3 Pa > Pv > PA
  • Blood flow in his region is determined by the arterial-veneous difference
  • The increased flow down this region is accomodated by the distension of capillaries as the pressures within them decrease down this zone.
Zone 4 Pa > Pv > PA
  • The compressing effect of intersitital pressure on the extra alveolar vessels tends to decrease blood flow at the lower levels.
Henry's Law
  • The solubility of a gas in a liquid is directly proportional to the partial pressure of the gas and inversely proportional to the temp of liquid
Henry's Law solubility coefficient
  • The solubility coefficient of a gas is the amount of the gas that will dissolve in a liquid at standard pressure and a specified temperature.
In the healthy individual in the upright position the V/Q ratio is highest in the lower lung regions. T or F
False
In the healthy individual in the upright position PAO2 is lowest in the upper lung regions. T or F
False
In the healthy individual in the upright position V/Q ratio is lowest in upper regions. T or F
False
In the healthy individual in the upright position PACO2 is highest in lower lung regions. T or F
True
The normal transit time for blood through the alveolar capillary system is about ?
0.75 second
Under normal resting conditions the diffusion of oxygen and carbon dioxide is usually completed in about ?
0.25 second
Which law states that the rate of gas diffusion is inversely proportional to the weight of gas ?
Graham's law
According to Fick's Law gas diffusion is ______ proportional to the difference in partial pressure of the gas between two sides
Directly
According to Fick's Law as the thickness decreases, gas diffusion _________.
Increases
According to Fick's law as pressure difference increases gas diffusion ______.
Increases
According to Fick's law  as the area decreases gas diffusion _______.
Decreases
Under normal circumstances the diffusio of gas is perfusion or diffusion limited ?
perfusion limited
In response to decreased alveolar oxygen pressure the pulmonary vascular system ________.
Constricts
In response to increased PCO2 level the pulmonary vascular system _______.
Constricts
In response to decreased pH the pulmonary vascular system _______
Constricts
In response to increased pulmonary arterial pressure the pulmonary vascular resistence ________.
Decreases
In response to increased left arterial pressure the pulmonary vascular resistence _______.
Decreases
In response to increased blood viscosity the pulmonary vascular resistence will ________.
Increase
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