phsiology 3 Flashcards
What tends to decrease airway resistance?
Asthma
Stimulation by sympathetic fibers
Treatment with acetylcholine
Exhalation to residual volume
Stimulation by sympathetic fibers
Which of the following would be expected to increase the measured airway resistance?
Stimulation of parasympathetic nerves to the lungs Low lung volumes Release of histamine by mast cells Forced expirations All of the above
All of the above
Several students are trying to see who can generate the highest expiratory flow. Which muscle is most effective at producing a maximal effort?
Diaphragm Internal intercostals External intercostals Rectus abdominis Sternocleidomastoid
Rectus abdominis
With a slow decrease in left heart function, which of the following will minimize the formation of pulmonary edema?
An increase in plasma protein concentration due to fluid loss
Increase in the negative interstitial hydrostatic pressure
Increased pumping of lymphatics
Increase in the concentration of interstitial proteins
Increased pumping of lymphatics
A 22-year-old woman has a pulmonary compliance of 0.2 L/cm H2O and a pleural pressure of −4 cm H2O. What is the pleural pressure (in cm H2O) when the woman inhales 1.0 liter of air? −6 −7 −8 −9 −10
−9
A patient has a dead space of 150 milliliters, FRC of 3 liters, tidal volume (VT) of 650 milliliters, expiratory reserve volume (ERV) of 1.5 liters, total lung capacity (TLC) of 8 liters, and respiratory rate of 15 breaths/min. What is the residual volume (RV)? A) 500 milliliters B) 1000 milliliters C) 1500 milliliters D) 2500 milliliters E) 6500 milliliter
C) 1500 milliliters
A patient has a dead space of 150 milliliters, FRC of 3 liters, VT of 650 milliliters, ERV of 1.5 liters, TLC of 8 liters, and respiratory rate of 15 breaths/min. What is the alveolar ventilation (Va)? A) 5 L/min B) 7.5 L/min C) 6.0 L/min D) 9.0 L/min
B) 7.5 L/min
What happens during exercise?
A) Blood flow is uniform throughout the lung
B) Lung-diffusing capacity increases because blood flow is continuous in all pulmonary capillaries
C) Pulmonary blood volume decreases
D) The transit time of blood in the pulmonary capillaries does not change from rest
B) Lung-diffusing capacity increases because blood
flow is continuous in all pulmonary capillaries
. A person with normal lungs has an oxygen (O2) consumption of 750 ml O2/min. The hemoglobin (Hb) concentration is 15 g/dl. The mixed venous saturation is 25%. What is the cardiac output? A) 2500 ml/min B) 5000 ml/min C) 7500 ml/min D) 10,000 ml/min E) 20,000 ml/min
B) 5000 ml/min
A cardiac catheterization is performed in a healthy adult. The blood sample withdrawn from the catheter shows 60% O2 saturation, and the pressure recording shows oscillations from a maximum of 27 mm Hg to a minimum of 12 mm Hg. Where was the catheter tip located? A) Ductus arteriosus B) Foramen ovale C) Left atrium D) Pulmonary artery E) Right atrium
D) Pulmonary artery
If alveolar surface area is decreased 50% and pulmonary edema leads to a doubling of diffusion distance, how does diffusion of O2 compare with normal? A) 25% increase B) 50% increase C) 25% decrease D) 50% decrease E) 75% decrease
E) 75% decrease
Which diagram in the above figure best illustrates the pulmonary vasculature when the cardiac output has increased to a maximum extent? A) A B) B C) C D) D E) E
A) A
A human experiment is being performed in which forearm blood flow is being measured under a variety of conditions. The forearm is infused with a vasodilator, resulting in an increase in blood flow. Which of the following occurs?
A) Tissue interstitial partial pressure of oxygen (Po2) will increase
B) Tissue interstitial partial pressure of carbon dioxide (Pco2) will increase
C) Tissue pH will decrease
A) Tissue interstitial partial pressure of oxygen (Po2) will increase
Blood gas measurements are obtained in a resting patient who is breathing room air. The patient has an arterial content of 19 ml O2/min with a Po2 of 95. The mixed venous O2 content is 4 ml O2/100 ml blood. Which condition does the patient have?
A) An increase in physiological dead space
B) Pulmonary edema
C) A low Hb concentration
D) A low cardiac output
D) A low cardiac output
. A normal male subject has the following initial conditions (in the steady state): Arterial Po2 = 92 mm Hg Arterial O2 saturation = 97% Venous O2 saturation = 20% Venous Po2 = 30 mm Hg Cardiac output = 5600 ml/min O2 consumption = 256 ml/min Hb concentration = 12 gm/dl If you ignore the contribution of dissolved O2 to the O2 content, what is the venous O2 content? A) 2.2 ml O2/100 ml blood B) 3.2 ml O2/100 ml blood C) 4 ml O2/100 ml blood D) 4.6 ml O2/100 ml blood E) 6.2 ml O2/100 ml blood F) 10.8 ml O2/100 ml blood G) 16 ml O2/100 ml blood
B) 3.2 ml O2/100 ml blood