40. Circulatory System

When you exhale, __________.

In the alveoli and lung capillaries, carbon dioxide and oxygen are exchanged by means of __________.

Which structure in a human is most similar in function to the gill lamellae of a fish?

What happens when the CO₂ level from cellular respiration increases in the blood?

What is the major reason that land-dwelling mammals evolved lungs rather than gills as a primary respiratory organ?

What is the correct order of structures through which air passes as it is inhaled by a typical mammal?

Which of the following components of the mammalian gas exchange system has a surface covered by a thin film of fluid without cilia?

Countercurrent flow in the gills of a fish __________.

Which respiratory organ is most often found only in fully aquatic animals?

Gas exchange in the gills of a bony fish is maximized by which of the following?

For a body surface to be a respiratory surface, it must __________.

Complete the following concept map to review some of the concepts of gas exchange. a. b. c. d. e. f. g.

When you hold your breath, which of the following first leads to the urge to breathe?a. falling CO2b. falling O2c. falling pH of the bloodd. rising pH of the blood

Which of the following promotes oxygen release from hemoglobin?a. a decrease in temperatureb. an increase in O2 levelc. a decrease in pHd. a decrease in carbonic anhydrase activity

When you hold your breath, which of the following blood gas changes first leads to the urge to breathe?a. rising O2b. falling O2c. rising CO2c, falling CO2