H. V. Wilson worked with sponges to gain some insight into exactly what was responsible for holding adjacent cells together. He exposed two species of differently pigmented sponges to a chemical that disrupted intercellular junctions, and the cells of the sponges dissociated. Wilson then mixed the cells of the two species and removed the chemical that caused the cells to dissociate. Wilson found that the sponges reassembled into two separate species. The cells from one species did not interact or form associations with the cells of the other species.

How do you explain the results of Wilson's experiments?

#Question id: 11070

#Unit 7. System Physiology – Animal

A patient has a dead space of 150 ml, functional residual capacity of 3 L, tidal volume of 650 ml, expiratory reserve volume of 1.5 L, a total lung capacity of 8 L, respiratory rate of 15 breaths/min. What is the alveolar ventilation?

#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?