[Campbell Biology P.973] A scientist observes a newly discovered vertebrate with a circulato... | Practice Question

A scientist observes a newly discovered vertebrate with a circulatory system resembling that of a typical fish, as described in the text and Figure 42.4a. If a drop of oxygen-poor blood leaves the ventricle of this creature, what is the most likely path it will take to become oxygen-rich and then supply a body capillary bed?

  • A: Ventricle -> Gills (oxygenation) -> Atrium -> Body capillaries.
  • B: Ventricle -> Gills (oxygenation) -> Body capillaries -> Atrium.
  • C: Ventricle -> Body capillaries -> Gills (oxygenation) -> Atrium.
  • D: Ventricle -> Atrium -> Gills (oxygenation) -> Body capillaries.

Explanation

In single circulation fish , oxygen-poor blood is pumped from the ventricle to the gills for oxygenation. From the gills, the now oxygen-rich blood flows directly to the body's capillary beds to supply tissues, and then returns to the atrium. It does not return to the heart after the gills before going to the body.