EXAM III Pulmonary Flashcards
Define minute and alveolar ventilation and equations
Total volume of gases moved in/out of lungs per minute (VE)
Total volume of gases that enter spaces participating in gas exchange/minute (VA)
Define pleural pressure
Pressure of fluid between parietal pleura and visceral pleura
Define alveoli pressure
Pressure of fluid in the alveoli
Define Transpulmonary pressure
Pressure difference b/w alveolar pressure and pleura pressure
What are the two circulations of the lung? Which circulation has a larger compliance?
High Pressure, Low Flow/Volume
thoracic aorta, bronchiole arteries, trachea, bronchial tree, adventitia CT
Low Pressure, High Flow/Volume - larger compliance
pulmonary artery and branches –> alveoli
What are the agents that constrict and dilate pulmonary arterioles?
Epi/NEpi
Angiotensin II
Prostaglandins
What effect does heavy exercise have on blood flow through the lungs? Why does this cause a minimal rise in pulmonary arterial pressure?
Distends capillaries to increase flow rate & increases the amount that are open
Increases pulmonary arterial pressure
What effect does left-sided heart failure have on left atrial pressure? (left side = body; right side = pulmonary)
Increase in blood pressure
Pressure build up in pulmonary circulation
Blood damming in left atrium
What are the four forces that are involved in hydrostatic and colloid forces?
capillary hydrostatic pressure = out
interstitial fluid colloid osmotic pressure = out
Interstitial fluid hydrostatic pressure = in
capillary osmotic pressure = in
Inwards are subtracted from outward force
What are the most common causes of pulmonary edema and at what capillary pressure level does it occurs?
Left-sided heart failure or mitral valve relapse
Damage to pulmonary blood capillary membranes; infections, breathing noxious substances
> 25 mmHg
Mitral valve disease
What are the results of bronchial obstruction and hypoxia in relation to blood flow?
An obstruction causes constriction of vessels that are supplying the poorly ventilated alveoli which is due locally to low alveolar PO2 effect on vessels, a drop in pH due to CO2 accumulation which causes vasoconstriction in pulmonary vessels and vasodilation in other tissues
Hypoxia = increases pressure in pulmonary artery; reduction of blood flow to a portion of the lung
Lowers alveolar PCO2 resulting in constriction of bronchi supplying that portion
(what happens in lungs is opposite of what happens elsewhere)
Define Dalton’s law
The total pressure extered by the mixture of non-reactive gases is equal to the sum/all of the partial pressures of individual gases
Define Boyle’s Law
Boiled water = pressure
Fixed amount of an ideal gas kept at a fixed temp.
Pressure is inversly proportional to Volume
Define Henry’s Law
At constant temp., amount of gas that dissolves in a given volume is directly proportional to the partial pressure of that gas in equilibrium with that liquid
What are the factors that control oxygen concentration in the alveoli?
Rate of absorption of oxygen into the blood
Rate of new oxygen into the lungs (alveolar ventilation)
Why can’t alveolar ventilation increase PO2 above 149 mmHg under normal conditions?
Due to the partial pressure of oxygen in the atm
The functional residual capacity of lungs = 2300ml; only 350 ml of new air is brought into alveoli w/ each normal inspiration and same amount is expired; multiple breaths are required to exchange most of alveolar air (only one 7th is replaced by new atm air)
Must increase oxygen levels in order to increase!!!
What are the factors that shift the oxygen-Hb dissociation curve to the right?
BPG
Increased CO2
Increased [H+]
Increased temp.
Define the Bohr and Haldane effect
Bohr = lower pH causes greater blood [CO2]; right shift
a decrease in blood [CO2] = left shift
Haldane = oxygen displaces CO2 and causes a left shift
