Fossils of Thrinaxodon, a species that lived during the Triassic period, have been found in both South Africa and Antarctica. Thrinaxodon had a reptile-like skeleton and laid eggs, but small depressions on the front of its skull suggest it had whiskers and, therefore, fur. Thrinaxodon may have been warm-blooded. The fossils of Thrinaxodon are consistent with the hypothesis that ________.

#Question id: 11071

#Unit 7. System Physiology – Animal

At the end of inhalation, with an open glottis, the pleural pressure is

#Question id: 11072

#Unit 7. System Physiology – Animal

The following diagram shows pulmonary airway resistance expressed as a function of pulmonary volume. Which relationship best describes the normal lung?

#Question id: 11073

#Unit 7. System Physiology – Animal

The respiratory passageways have smooth muscle in their walls. Which of the following best describes the effect of acetylcholine and epinephrine on the respiratory passageways?

#Question id: 11074

#Unit 7. System Physiology – Animal

A 30-year-old woman performs a valsalva maneuver about 30 min after eating lunch. Which of the following best describes the changes in pulmonary and systemic blood volumes that occur in this woman?

#Question id: 11075

#Unit 7. System Physiology – Animal

A 65-year-old man with emphysema due to 34 years of cigarette smoking is admitted to hospital due to dyspnea. With further tests the mean pulmonary arterial pressure is determined to be 45 mm Hg at rest. He is hypoxic (PO2 = 49 mm Hg), hypercapnic (85 mm Hg), and slightly acidotic. The cardiovascular and oxygen changes are due to which of the following?

#Question id: 11076

#Unit 7. System Physiology – Animal

Which of the following will decrease pulmonary blood flow resistance?