NURS242 EXAM 3 QUESTIONS AND
ANSWERS
What is ventilation? - ANS the movement of air into and out of the lungs
What is perfusion? - ANS the circulation of blood through the lungs
What are central chemoreceptors responsive to? - ANS increased H+ in the brain ECF;
increased PaCO2;
"hypercarbic drive"
What are peripheral chemoreceptors responsive to? - ANS decreased pH;
increased PaCO2;
decreased PaO2;
"hypoxic drive"
What are elastic forces? - ANS lungs recoil due to elastin, collagen, fibrin
What are surface forces? - ANS surface tension due to water-air interface
What is airway resistance? - ANS opposition to flow caused by the forces of friction; primarily
determined by airway radius
What is the distensibility of the lungs? - ANS ease with which the lungs can be inflated
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,What is lung distensibility increased in? - ANS neonates and children;
emphysema
What is lung distensibility decreased in? - ANS elderly;
pneumonia, pulmonary edema, ARDS, atelectasis, fibrosis
What is surfactant? - ANS complex substance lining the alveoli and smallest bronchioles
containing phospholipids and a number of apoproteins which reduces surface tension
throughout the lungs, thereby contributing to its general compliance;
stabilizes the alveoli and keeps them dry
What produces surfactant? - ANS produced by the Type II alveolar cells
What is Ohm's law? - ANS velocity = driving force/resistance
What is Poiseuille law? - ANS resistance = (8 x viscosity x length) / (pi x radius^4)
What happens if the radius in the lungs goes down? - ANS the resistance goes up
How is the ventilation distributed in the lungs? - ANS the top of the lungs are more
distended and less compliant whereas the lower lung is small and highly compliant
What factors affect lung perfusion? - ANS lung capacitance;
low resistance system;
flow influenced by gravity;
resistance primarily determined by vessel radius
What does hypoxia lead to? - ANS vasoconstriction of pulmonary vessels
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,What does prolonged hypoxia lead to? - ANS pulmonary hypertension
What factors affect alveolar-capillary diffusion? - ANS capillary permeability;
surface area available for diffusion;
concentration gradient for the gas;
distance for diffusion
What causes right shifts (decreased affinity) in Hemoglobin-O2 affinity? - ANS acidemia;
hyperthermia;
hypercarbia
What causes left shifts (increased affinity) in Hemoglobin-O2 affinity? - ANS alkalemia;
hypothermia;
hypocarbia
What is hypoxemia? - ANS deficient blood oxygen;
low PaO2;
low O2 saturation
What is hypoxia? - ANS decreased tissue oxygen
What is hypoxic hypoxia? - ANS decreased tissue oxygen caused by decreased respirations
What is anemic hypoxia? - ANS decreased tissue oxygen caused by decreased hemoglobin
What is circulatory hypoxia? - ANS decreased tissue oxygen caused by decreased blood flow
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, What is histotoxic hypoxia? - ANS decreased tissue oxygen caused by increased toxic
substance
What is ischemia? - ANS greatly reduced or interrupted flow through the arterial system,
producing significant tissue hypoxia
What is hypercapnia? - ANS increased level of CO2 in the blood
What are S&S of acute hypoxia? - ANS dyspnea; restlessness; palpitations; agitation;
headache; tremors; diaphoresis; respiratory distress; cyanosis; tachypnea; tachycardia;
dysrhythmias; hypertension; lethargy; confusion to coma
What are some effects of hypercapnia? - ANS respiratory acidosis (decreased pH from
increase in CO2); lethargy and confusion; increased HR and BP; flushed skin; arrhythmias;
seizures; coma; death
What is dyspnea? - ANS subjective feeling of being SOB
What does dyspnea lead to? - ANS decreased sense of wellness which may cause
psychological and social consequences
What is the leading cause of cancer death? - ANS lung cancer
What is lung cancer most likely caused by? - ANS cigarette smoking;
asbestos;
familial predisposition
What are the manifestations of lung cancer? - ANS cough, hemoptysis (blood in cough
sputum);
hoarseness;
chest pain;
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ANSWERS
What is ventilation? - ANS the movement of air into and out of the lungs
What is perfusion? - ANS the circulation of blood through the lungs
What are central chemoreceptors responsive to? - ANS increased H+ in the brain ECF;
increased PaCO2;
"hypercarbic drive"
What are peripheral chemoreceptors responsive to? - ANS decreased pH;
increased PaCO2;
decreased PaO2;
"hypoxic drive"
What are elastic forces? - ANS lungs recoil due to elastin, collagen, fibrin
What are surface forces? - ANS surface tension due to water-air interface
What is airway resistance? - ANS opposition to flow caused by the forces of friction; primarily
determined by airway radius
What is the distensibility of the lungs? - ANS ease with which the lungs can be inflated
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,What is lung distensibility increased in? - ANS neonates and children;
emphysema
What is lung distensibility decreased in? - ANS elderly;
pneumonia, pulmonary edema, ARDS, atelectasis, fibrosis
What is surfactant? - ANS complex substance lining the alveoli and smallest bronchioles
containing phospholipids and a number of apoproteins which reduces surface tension
throughout the lungs, thereby contributing to its general compliance;
stabilizes the alveoli and keeps them dry
What produces surfactant? - ANS produced by the Type II alveolar cells
What is Ohm's law? - ANS velocity = driving force/resistance
What is Poiseuille law? - ANS resistance = (8 x viscosity x length) / (pi x radius^4)
What happens if the radius in the lungs goes down? - ANS the resistance goes up
How is the ventilation distributed in the lungs? - ANS the top of the lungs are more
distended and less compliant whereas the lower lung is small and highly compliant
What factors affect lung perfusion? - ANS lung capacitance;
low resistance system;
flow influenced by gravity;
resistance primarily determined by vessel radius
What does hypoxia lead to? - ANS vasoconstriction of pulmonary vessels
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,What does prolonged hypoxia lead to? - ANS pulmonary hypertension
What factors affect alveolar-capillary diffusion? - ANS capillary permeability;
surface area available for diffusion;
concentration gradient for the gas;
distance for diffusion
What causes right shifts (decreased affinity) in Hemoglobin-O2 affinity? - ANS acidemia;
hyperthermia;
hypercarbia
What causes left shifts (increased affinity) in Hemoglobin-O2 affinity? - ANS alkalemia;
hypothermia;
hypocarbia
What is hypoxemia? - ANS deficient blood oxygen;
low PaO2;
low O2 saturation
What is hypoxia? - ANS decreased tissue oxygen
What is hypoxic hypoxia? - ANS decreased tissue oxygen caused by decreased respirations
What is anemic hypoxia? - ANS decreased tissue oxygen caused by decreased hemoglobin
What is circulatory hypoxia? - ANS decreased tissue oxygen caused by decreased blood flow
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, What is histotoxic hypoxia? - ANS decreased tissue oxygen caused by increased toxic
substance
What is ischemia? - ANS greatly reduced or interrupted flow through the arterial system,
producing significant tissue hypoxia
What is hypercapnia? - ANS increased level of CO2 in the blood
What are S&S of acute hypoxia? - ANS dyspnea; restlessness; palpitations; agitation;
headache; tremors; diaphoresis; respiratory distress; cyanosis; tachypnea; tachycardia;
dysrhythmias; hypertension; lethargy; confusion to coma
What are some effects of hypercapnia? - ANS respiratory acidosis (decreased pH from
increase in CO2); lethargy and confusion; increased HR and BP; flushed skin; arrhythmias;
seizures; coma; death
What is dyspnea? - ANS subjective feeling of being SOB
What does dyspnea lead to? - ANS decreased sense of wellness which may cause
psychological and social consequences
What is the leading cause of cancer death? - ANS lung cancer
What is lung cancer most likely caused by? - ANS cigarette smoking;
asbestos;
familial predisposition
What are the manifestations of lung cancer? - ANS cough, hemoptysis (blood in cough
sputum);
hoarseness;
chest pain;
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