When researchers first discovered that airflow through a bird’s paleopulmonal parabronchi is unidirectional, the question arose as to whether gas exchange is countercurrent, cocurrent, or cross- current. Some ingenious investigators carried out experiments in which they measured the efficiency of gas exchange between air and blood in duck lungs when parabronchial airflow was in its normal direction and when the direction of parabronchial airflow was artificially reversed. The efficiency did not change. How is this evidence against countercurrent and cocurrent gas exchange? How is this evidence for cross-current exchange?

When researchers first discovered that airflow through a bird’s paleopulmonal parabronchi is unidirectional, the question arose as to whether gas exchange is countercurrent, cocurrent, or cross- current. Some ingenious investigators carried out experiments in which they measured the efficiency of gas exchange between air and blood in duck lungs when parabronchial airflow was in its normal direction and when the direction of parabronchial airflow was artificially reversed. The efficiency did not change. How is this evidence against countercurrent and cocurrent gas exchange? How is this evidence for cross-current exchange?

Biology 2e

2nd Edition

ISBN:9781947172517

Author:Matthew Douglas, Jung Choi, Mary Ann Clark

Publisher:Matthew Douglas, Jung Choi, Mary Ann Clark

Chapter39: The Respiratory System

Section: Chapter Questions

Problem 1VCQ: Figure 39.7 Which of the following statements about the mammalian respiratory system is false? When...

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Similar questions

Figure 39.7 Which of the following statements about the mammalian respiratory system is false? When we breathe in, air travels from the pharynx to the trachea. The bronchioles branch into bronchi. Alveolar ducts connect to alveolar sacs. Gas exchange between the lung and blood takes place in the alveolus.
EVOLUTION LINK Aquatic mammals such as whales and dolphins use lungs rather than gills for gas exchange. Propose a hypothesis to explain why.
The alveoli and blood capillaries make up the gas exchange surface of the lungs, and as the arrows in the diagram (Figure 3) illustrate, this is where oxygen and carbon dioxide move in a particular direction. a) With reference to simple diffusion, explain why oxygen and carbon dioxide move in the directions illustrated by the arrows. b) The gas exchange surface is specifically adapted to maximise the transport of oxygen and carbon dioxide in these illustrated directions. Explain at least three of these adaptations.
Describe some structural and functional features that are commonto all gas-exchange surfaces in animals.
Which route does a pocket of air follow through the avian respiratory system during the first inhalation and exhalation? a.) Air enters the lungs in the first inhalation and is pused to the anterior air sacs in the first exhalation. b.) Air enters the lungs in the first inhalation and is pused to the posterior air sacs in the first exhalation. c.) Air enters the anterior airs sacs in the first inhalation and is pushed to the posterior air sacs in the first exhalation. d.) Ait enters the posterior air sacs in the first inhalation and is pushed to the lungs in the first exhalation.
Define the term “exchange surface” and list four common features of gas-exchange organs in animals.
Compare the two types of gas exchange systems in invertebrates. Based on your observation of the tracheal system of an aquatic insect: mosquito wriggler) & book lung systems (in invertebrates: spider (Araneae), explain how these systems are similar and how they differ from one another. (i.e. structures involved & relation to circulatory system). In cockroach, do the spiracles occur in pairs? What do you think happens if you block oxygen from coming into the body and prevent carbon dioxide from leaving?
Please compare tracheal systems vs. avian lungs by discussing the differences and similarities in the system's responses to temperature and concentration gradient
Discuss Tidal, residual, minimal air in Gaseous Exchange in Animals
Explain some structural and functional features that are common to all gas-exchange surfaces in animals.
At various points throughout Earth’s geological history, atmospheric and oceanic oxygen levels have been different than they are today. If future oxygen levels in the ocean become higher than they are today, what effect do you think this will have on the relative frequencies with which ram ventilation or buccopharyngeal pumping are used by aquatic vertebrates? Please explain your answer.
True or False: By comparing the evaginated respiratory structures of aquatic organisms (e.g. gills, skin folds) with the invaginated respiratory structures of terrestrial organisms (below), we can conclude that invaginated lungs and tracheal systems are an adaptation to terrestrial life.